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MyDeficiencies

Setmelanotide

Melanocortin-4 receptor (MC4R) agonist, centrally acting antiobesity peptide

Also sold as Imcivree.

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Findings for this medication

Research about this medication, graded for how strongly each finding can be attributed to it. Nothing here describes your own levels.

Setmelanotide has no classical pharmacokinetic depletion mechanism. Its own label states it is "expected to be metabolized into small peptides by catabolic pathways" (ordinary proteolysis, not cytochrome P450 oxidation), it has "low potential for pharmacokinetic drug-drug interactions related to cytochrome P450 (CYP), transporters and plasma protein binding," and it is given by subcutaneous injection only, so the chelation, gastric-pH, bile-acid-sequestration, and transporter-competition mechanisms that drive most drug-nutrient interactions do not apply. About 39% is excreted unchanged in urine over 24 hours, with the remainder cleared by peptide catabolism, and mild renal impairment raises exposure modestly (the label does not recommend use in moderate-to-severe renal impairment, an exposure caution rather than a nutrient-handling one). No CYP induction or inhibition is documented at any level.

Melanocortin-4 receptor (MC4R) agonist, centrally acting antiobesity peptide · ATC A08AA12 · also sold as Imcivree · reviewed 2026-09-28. This describes research about the medication. It does not say anything about your own levels or health.

How to read the evidence grades

These colours describe how strongly a finding can be attributed to the medication in the research. They are not a severity score and they say nothing about your own health.

Grades describe how strongly a finding can be attributed to Setmelanotide in the research — not how common it is, how serious it would be, and not anything about you personally.

Red — Severe
Two or more independent Tier A sources, this drug in the cohort, the nutrient directly measured, consistent direction, clinically meaningful magnitude, a named mechanism, no substantial contradicting Tier A evidence.
Orange — Moderate
At least one Tier A source with this drug in the cohort showing a real but bounded deficit: an exposure window, a subgroup, low frequency, or a functional rather than circulating deficit.
Yellow — Low
Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction.
Not graded — disclosed evidence gap
Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result.Source definition: Not gradeable under the rules above because nothing has been measured. Published as a documented gap, never as reassurance that there is no effect.

What the research found

Acute adrenal insufficiency, bounded to patients with pre-existing secondary adrenal insufficiency

Orange — Moderate

See study details

In the acquired hypothalamic obesity trial, serious adverse reactions of acute adrenal insufficiency occurred in 5% of setmelanotide-treated patients who already had secondary adrenal insufficiency from their hypothalamic injury, versus 0% on placebo; this is a drug-precipitated crisis in an already-vulnerable HPA axis, not a new endocrinopathy the drug creates in a previously normal axis, and it is a hormonal, not classical-nutrient, disturbance graded here for completeness under mechanism class F (hormonal disturbance).

Full detail and limits

What the grade means here: At least one Tier A source with this drug in the cohort showing a real but bounded deficit: an exposure window, a subgroup, low frequency, or a functional rather than circulating deficit. orange

Limits on what this shows

  • Key negative/null findings: Not reported in the label excerpt; the BBS and POMC/PCSK1/LEPR genetic-deficiency trials, whose patients do not have acquired hypothalamic structural injury as their underlying etiology (though POMC deficiency itself causes ACTH deficiency by a different, disease-inherent mechanism, see Headline finding), are not described as showing this same signal in the sources reviewed.
  • At-risk subgroups: Explicitly restricted by the label to patients with acquired HO who already have secondary adrenal insufficiency. Not described as a risk in patients with a normal HPA axis.
  • Counter-evidence on record: None located; this review could not access the full Trial 1 clinical study report or the two pivotal POMC/LEPR and BBS papers (Clement et al. 2020, Lancet Diabetes Endocrinol, paywalled with no open-access location per Unpaywall; Haws et al. 2020, Diabetes Obes Metab, technically hybrid open access via Wiley but returned an HTTP 403 to automated fetch) to check for a more granular denominator or null-comparator detail beyond what the current label itself states.

Regulatory status

IMCIVREE US PI, Section 5.5, Warnings and Precautions: "In a clinical trial of adults and pediatric patients aged 4 years and older with acquired HO and secondary adrenal insufficiency, serious adverse reactions related to acute adrenal insufficiency were reported by 5% of IMCIVREE-treated patients and no placebo-treated patients." Labeled monitoring: "In patients with secondary adrenal insufficiency, monitor for clinical signs of acute adrenal insufficiency."

Population evidence

Acquired HO registration trial (Trial 1), ages 4 and older, randomized placebo-controlled period; exact denominator not stated in the label excerpt reviewed, incidence reported as a percentage only. This is the only setmelanotide-specific data source found for this finding.

Mechanism

Named indirectly: the acquired-HO population is enriched for pre-existing hypothalamic-pituitary damage (the same injury, often from craniopharyngioma or its treatment, that causes the obesity itself), which frequently already includes impaired ACTH/cortisol reserve. The label restricts this warning specifically to "patients with secondary adrenal insufficiency," meaning the mechanism described is a drug-associated precipitant of crisis in an already-compromised axis, not de novo suppression of a normal one; no further mechanistic detail (e.g., whether via appetite/intake changes affecting steroid requirements, or a direct HPA interaction) is given in the label text located.

Counter-evidence held on record

This is a hormonal (HPA-axis) disturbance in an already-compromised endocrine system, not a nutrient or vitamin deficiency, and supplementation of any kind is not the relevant response. Patients with known secondary adrenal insufficiency on hydrocortisone replacement should have their glucocorticoid regimen and sick-day dosing plan reviewed with their prescriber before and during setmelanotide therapy; this is a labeled monitoring requirement, not an optional caution.

Sodium imbalance, bounded to concomitant central diabetes insipidus

Orange — Moderate

See study details

The label carries a dedicated warning for sodium imbalance (hyponatremia or hypernatremia) specifically in acquired HO patients with concomitant central diabetes insipidus, tied to changes in fluid intake and hydration status; this is a dilutional/regulatory electrolyte disturbance in a population that already lacks normal thirst/ADH regulation, not a classical dietary sodium deficiency, and the framing caution applies per Hard Rule 5.

Full detail and limits

What the grade means here: At least one Tier A source with this drug in the cohort showing a real but bounded deficit: an exposure window, a subgroup, low frequency, or a functional rather than circulating deficit. orange

Limits on what this shows

  • Key negative/null findings: Not reported in the label excerpt reviewed. No sodium-imbalance warning is present for the BBS or POMC/PCSK1/LEPR genetic-deficiency indications, which are not associated with central DI at the same rate as acquired HO.
  • At-risk subgroups: Explicitly restricted to acquired HO patients with concomitant central diabetes insipidus.
  • Counter-evidence on record: None located; same access limitation as the adrenal-insufficiency entry above (pivotal trial full reports not accessible this session).

Regulatory status

IMCIVREE US PI, Section 5.6, Warnings and Precautions (Sodium Imbalance): recommends monitoring "serum sodium levels with changes in fluid intake and hydration status" in acquired HO patients with concomitant central diabetes insipidus.

Population evidence

Acquired HO registration trial population; exact incidence figures for sodium abnormalities were not located in the label excerpt reviewed (only the existence and wording of the warning itself was confirmed).

Mechanism

Named: acquired HO frequently co-occurs with central diabetes insipidus (both are consequences of the same hypothalamic structural injury, most often craniopharyngioma or its surgical/radiation treatment). Central DI patients depend on deliberate, thirst-driven fluid intake to compensate for impaired ADH secretion; a drug that changes appetite, satiety, or general intake behavior in this population has a plausible route to destabilizing that compensatory fluid balance in either direction. This is a disease-drug interaction mechanism (class F, hormonal/dilutional disturbance), not a renal sodium-wasting or sodium-retention effect of setmelanotide itself.

Counter-evidence held on record

This can run in either direction (hyponatremia or hypernatremia) and is not a sodium-deficiency-to-be-corrected-by-supplementation finding; it is an instruction to monitor serum sodium and manage fluid intake under clinical guidance, particularly around any change in appetite or eating pattern after starting setmelanotide, per Hard Rule 5.

The five body-system areas

Each finding is counted once, in a single area. Where a study is mentioned in a second area it is context only.

Mitochondrial Burden

Each finding below is counted once, in this area only.

Mitochondrial burden, reverse-direction

Yellow — Low

See study details

A directly opened 2020 mechanistic study found that the MC4R agonist RO27-3225, a different molecule from setmelanotide, prevented ethanol-induced mitochondrial membrane potential loss and restored ATP production in cultured rat hippocampal neurons; this is class-level, cell-culture evidence for the receptor target setmelanotide also activates, running in a protective rather than a depletion direction, not a setmelanotide-specific or in vivo finding.

Full detail, limits and 4 references

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. yellow

Limits on what this shows

  • Key negative/null findings: None located for this specific pairing. Two further MC4R-agonist/mitochondria papers were identified bibliographically via Crossref this revision (Zhang HH et al., "Melanocortin 4 Receptor Activation Attenuates Mitochondrial Dysfunction in Skeletal Muscle of Diabetic Rats," J Cell Biochem 2017, DOI 10.1002/jcb.26062; Torres AK et al., "Stimulation of Melanocortin Receptor-4 (MC4R) Prevents Mitochondrial Damage Induced by Binge Ethanol Protocol in Adolescent Rat Hippocampus," Neuroscience 2020, DOI 10.1016/j.neuroscience.2020.05.005) whose titles describe the same protective direction, but both were paywalled (Wiley, Elsevier) and returned HTTP 403 to fetch; Unpaywall confirmed both as closed access with no open-access location. They are named in Sources and excluded from supporting this claim's content, per this protocol's prohibition on citing an unopened source, but their titles are consistent with, not contradictory to, the direction found in the one study that could be opened.
  • At-risk subgroups: Not applicable; this is a receptor-target-level mechanistic finding, not a subgroup risk.
  • Counter-evidence on record: None found for or against a mitochondrial-harm direction in any source opened this session; every mitochondria-related MC4R finding located, opened or title-only, points toward the receptor's activation being protective, not depleting.

Regulatory status

Not a labeled finding. The current DailyMed label contains no mitochondrial-function content of any kind.

Population evidence

Quintanilla RA, Perez MJ, Aranguiz A, Tapia-Monsalves C, Mendez G. "Activation of the Melanocortin-4 Receptor Prevents Oxidative Damage and Mitochondrial Dysfunction in Cultured Hippocampal Neurons Exposed to Ethanol." Neurotoxicity Research, 2020. DOI 10.1007/s12640-020-00204-1. Directly opened and read in full this revision. Cultured rat hippocampal neurons pre-treated with the MC4R agonist RO27-3225 (250 nM, 1 hour) before acute ethanol exposure (50 to 75 mM, 24 hours). Mitochondrial membrane potential loss induced by ethanol was prevented by RO27-3225 pre-treatment, and ATP production was significantly increased in ethanol-treated, RO27-3225-pretreated neurons versus ethanol alone. This is a cell-culture, non-setmelanotide, ethanol-toxicity model, not a setmelanotide or in vivo obesity-treatment study, and the cohort test therefore places it at Tier C, class extrapolation for setmelanotide specifically, even though it directly implicates the same MC4R target.

Mechanism

Named: MC4R activation triggers nuclear translocation of the Nrf-2 antioxidant transcription factor, which the authors propose upstream of the mitochondrial protection observed. This is a receptor-level (class) mechanism, not demonstrated for setmelanotide's specific binding kinetics or its approved patient populations.

Counter-evidence held on record

This is not evidence that setmelanotide harms mitochondria; the one directly opened study found the opposite direction using a different MC4R agonist in an unrelated ethanol-toxicity cell model. It should not be read as a basis for any mitochondrial-support supplement; no dose is recommended for a yellow-tier, class-extrapolated finding, and this entry exists because the mandatory Mitochondrial burden category requires evaluation for every medication regardless of the direction the evidence points.

  • Haws R, Brady S, Davis E, et al. Effect of setmelanotide, a melanocortin-4 receptor agonist, on obesity in Bardet-Biedl syndrome. — Pivotal BBS trial. Confirmed hybrid open access via Unpaywall (CC-BY-NC-ND, Wiley-hosted), but the PDF and landing-page URLs both returned HTTP 403 to automated fetch in this session and could not be opened; only the title, authors, and journal metadata (via Crossref and Unpaywall) are used here, not any content from the paper itself.Not independently opened this session; cited for bibliographic identification only, not as a source of extracted findings.
  • Quintanilla RA, Perez MJ, Aranguiz A, Tapia-Monsalves C, Mendez G. Activation of the Melanocortin-4 Receptor Prevents Oxidative Damage and Mitochondrial Dysfunction in Cultured Hippocampal Neurons Exposed to Ethanol. — Directly opened and read in full during the revision pass. The MC4R agonist RO27-3225 (250 nM, 1 hour pre-treatment) prevented ROS increase, mitochondrial membrane potential loss, and cytosolic calcium dysregulation, and increased ATP production and Nrf-2/NQO1 antioxidant-pathway activation, in cultured rat hippocampal neurons exposed to ethanol (50-75 mM, 24 h). Primary support for both the Mitochondrial burden and Oxidative stress entries (yellow, protective/reverse direction). Cell-culture study using RO27-3225, not setmelanotide; class extrapolation for this drug.
  • Zhang HH, Liu J, Qin GJ, Li XL, Du PJ, Hao X, Zhao D, Tian T, Wu J, Yun M, Bai YH. Melanocortin 4 Receptor Activation Attenuates Mitochondrial Dysfunction in Skeletal Muscle of Diabetic Rats. — Identified and bibliographically confirmed via Crossref during the revision pass (title, authors, journal, volume/pages/DOI). Wiley-published; returned HTTP 403 to fetch and Unpaywall confirmed closed access with no open-access location.Not independently opened this session; title named for context only, not used to support any graded claim's content.
  • Torres AK, Tapia-Rojas C, Cerpa W, Quintanilla RA. Stimulation of Melanocortin Receptor-4 (MC4R) Prevents Mitochondrial Damage Induced by Binge Ethanol Protocol in Adolescent Rat Hippocampus. — Identified and bibliographically confirmed via Crossref during the revision pass. Elsevier-published; returned no readable content to automated fetch and Unpaywall confirmed closed access with no open-access location.Not independently opened this session; title named for context only, not used to support any graded claim's content.

Oxidative Stress

Each finding below is counted once, in this area only.

Oxidative stress, reverse-direction

Yellow — Low

See study details

The same directly opened 2020 study found that the MC4R agonist RO27-3225 prevented an ethanol-induced rise in reactive oxygen species (ROS) in cultured hippocampal neurons via activation of the Nrf-2 antioxidant pathway; this is class-level, cell-culture evidence for the receptor target setmelanotide also activates, running in a protective rather than a depletion direction, not a setmelanotide-specific finding.

Full detail, limits and 2 references

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. yellow

Limits on what this shows

  • Key negative/null findings: None located for this specific pairing. A separate 2020 Neuropharmacology paper by an overlapping author group (Perez MJ et al., "NADPH Oxidase Contributes to Oxidative Damage and Mitochondrial Impairment Induced by Acute Ethanol Treatment in Rat Hippocampal Neurons," DOI 10.1016/j.neuropharm.2020.108100) was identified bibliographically via the same Crossref search as a companion paper from the same research program, but was not independently opened this session and is not cited as support.
  • At-risk subgroups: Not applicable; this is a receptor-target-level mechanistic finding, not a subgroup risk.
  • Counter-evidence on record: None found for or against an oxidative-stress-inducing direction in any source opened this session.

Regulatory status

Not a labeled finding. The current DailyMed label contains no oxidative-stress or antioxidant-marker content of any kind.

Population evidence

Quintanilla et al., Neurotoxicity Research 2020, DOI 10.1007/s12640-020-00204-1 (same source and cohort as the Mitochondrial burden entry above; see the Overlap map). RO27-3225 pre-treatment (250 nM, 1 hour) prevented the ROS increase, and the cytosolic calcium dysregulation, induced by ethanol (50 to 75 mM, 24 hours) in cultured rat hippocampal neurons, and increased Nrf-2 nuclear translocation and expression of the antioxidant enzyme NQO1 (NAD(P)H quinone oxidoreductase 1). Cell-culture, non-setmelanotide, ethanol-toxicity model; Tier C, class extrapolation for setmelanotide specifically.

Mechanism

Named: MC4R activation promotes Nrf-2 nuclear translocation and downstream antioxidant enzyme (NQO1) upregulation, directly measured in this study, not merely inferred.

Counter-evidence held on record

This is not evidence that setmelanotide increases oxidative stress; the one directly opened study found the opposite direction using a different MC4R agonist in an unrelated ethanol-toxicity cell model. It should not be read as a basis for antioxidant supplementation; no dose is recommended for a yellow-tier, class-extrapolated finding.

  • Haws R, Brady S, Davis E, et al. Effect of setmelanotide, a melanocortin-4 receptor agonist, on obesity in Bardet-Biedl syndrome. — Pivotal BBS trial. Confirmed hybrid open access via Unpaywall (CC-BY-NC-ND, Wiley-hosted), but the PDF and landing-page URLs both returned HTTP 403 to automated fetch in this session and could not be opened; only the title, authors, and journal metadata (via Crossref and Unpaywall) are used here, not any content from the paper itself.Not independently opened this session; cited for bibliographic identification only, not as a source of extracted findings.
  • Quintanilla RA, Perez MJ, Aranguiz A, Tapia-Monsalves C, Mendez G. Activation of the Melanocortin-4 Receptor Prevents Oxidative Damage and Mitochondrial Dysfunction in Cultured Hippocampal Neurons Exposed to Ethanol. — Directly opened and read in full during the revision pass. The MC4R agonist RO27-3225 (250 nM, 1 hour pre-treatment) prevented ROS increase, mitochondrial membrane potential loss, and cytosolic calcium dysregulation, and increased ATP production and Nrf-2/NQO1 antioxidant-pathway activation, in cultured rat hippocampal neurons exposed to ethanol (50-75 mM, 24 h). Primary support for both the Mitochondrial burden and Oxidative stress entries (yellow, protective/reverse direction). Cell-culture study using RO27-3225, not setmelanotide; class extrapolation for this drug.

Copper and Iron Balance

Copper and iron are assessed separately. Nothing here is counted twice.

Copper, theoretical increased utilization via pharmacologically driven melanogenesis

Yellow — Low

See study details

Setmelanotide causes generalized or focal skin hyperpigmentation and new or darkening melanocytic nevi in a majority of treated patients through direct MC1-receptor-driven stimulation of melanin synthesis; melanin synthesis is catalyzed by tyrosinase, a copper-dependent (type-3 binuclear copper center) enzyme, giving a plausible but never directly studied mechanistic route to increased copper utilization with sustained pharmacologic melanogenesis. This is graded on general enzymology, not on any setmelanotide-specific copper measurement.

Full detail and limits

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. yellow

Limits on what this shows

  • Key negative/null findings: None located; no study measuring copper status in a state of pharmacologically stimulated melanogenesis (setmelanotide or otherwise) was found or could be searched for exhaustively given this session's tooling limitations (see Tooling disclosure below and Sources).
  • At-risk subgroups: None identified; this is a theoretical, population-wide mechanism tied to the same patients who develop hyperpigmentation (a majority of those treated), not a defined higher-risk subgroup.
  • Counter-evidence on record: None found for or against; this is an unfalsified, untested mechanistic hypothesis, not a measured effect in either direction.

Regulatory status

Not a labeled copper interaction; the label documents the hyperpigmentation/melanogenesis effect itself as Tier A drug-specific (Section 5.4, 12.1) but makes no statement about copper, trace minerals, or any laboratory monitoring of mineral status.

Population evidence

Hyperpigmentation itself is well quantified and drug-specific: 78% of patients in the original 2020 registration cohort (accessdata.fda.gov label, Section 5.3/Table 1) and 67% in the BBS trial's controlled period versus 0% placebo (current DailyMed label, Section 6). No population has ever had copper status (serum copper, ceruloplasmin, or tissue copper) measured alongside this finding in any source located during this review.

Mechanism

Named and Tier B by general enzymology, not drug-specific: tyrosinase, the rate-limiting enzyme of melanin biosynthesis, requires a binuclear type-3 copper active site to oxidize its substrate (confirmed by direct review of a general reference source, see Sources); MC1-receptor activation increasing melanogenesis is documented drug-specific mechanism (IMCIVREE label, Section 12.1). The chain from "more melanin synthesis" to "more copper utilized by tyrosinase" to "measurable change in systemic copper status" has never been tested for this drug, or, as far as this review could determine, for any MC1/MC4R agonist.

Counter-evidence held on record

No copper deficiency has ever been measured in setmelanotide-treated patients. This entry exists because the mandatory Copper category requires an independent search rather than an assumption of "no mechanism," and a real, if untested, biochemical route was found. It should not be read as a basis for copper supplementation; no dose is recommended for a yellow-tier, mechanism-only finding.

Iron

Not graded — disclosed evidence gap

See study details

No setmelanotide-specific or melanocortin-pathway data connecting this drug to iron status, hepcidin, or ferroportin were located, and no circulating consumer claim about setmelanotide and iron exists to rebut.

Full detail and limits

What the grade means here: Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result. ungraded

Limits on what this shows

  • Why no grade: Both conditions for ungraded are met. (1) No Tier A/B/C evidence: the label contains no iron, ferritin, hemoglobin, or hematocrit content of any kind. A direct Crossref search for the melanocortin system (MC4R, alpha-MSH, POMC) crossed with iron metabolism, hepcidin, and ferroportin returned eight results, every one of which was confirmed, on review of the returned titles, to concern the hepcidin-ferroportin iron-homeostasis system on its own, with zero melanocortin-pathway involvement in any of them. This is a clean negative result, not a blocked search. (2) No circulating claim: see Fails verification.

Tooling disclosure

A dedicated PubMed search ("setmelanotide iron") returned only an automated reCAPTCHA/bot-verification page, not results, so that specific channel could not independently confirm the Crossref negative result. Europe PMC, Semantic Scholar, and OpenAlex were unavailable throughout the original review (see access-note and the Oxygen delivery/utilization entry below for this dossier's fuller, session-by-session tooling disclosure). The Crossref search that did complete for this category is treated as sufficient given it returned a clean, on-topic negative rather than an error, but this is disclosed as a narrower confirmation (one working channel, not the full recommended set) than ideal. This category was not re-searched in the subsequent revision pass, which was scoped to Gut microbiome risk, Mitochondrial burden, Oxidative stress, and Oxygen delivery/utilization; Iron's clean-negative status stands as originally found.

Gut Microbiome Risk

Each finding below is counted once, in this area only.

Gut microbiome risk, theoretical modulation via the hypothalamic POMC/MC4R-to-gut circuit

Yellow — Low

See study details

Two directly opened animal studies establish that hypothalamic melanocortin-pathway activity, the same circuit setmelanotide's MC4R agonism engages, is mechanistically capable of altering gut microbiota composition, in opposite directions depending on whether the pathway is activated or lost; neither study used setmelanotide, and no human or setmelanotide-specific microbiome measurement was located.

Full detail, limits and 2 references

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. yellow

Limits on what this shows

  • Key negative/null findings: In the Toledo et al. study, AgRP-neuron (orexigenic) chemogenetic activation produced only minimal microbiota changes compared to POMC-neuron activation, and ghrelin produced only modest alterations, an internal negative comparison within the same paper. No study measuring gut microbiota in setmelanotide-treated patients, or in any MC4R-agonist-treated animal model, was located.
  • At-risk subgroups: None defined for setmelanotide specifically. The genetic conditions setmelanotide treats (POMC, PCSK1, LEPR deficiency; Bardet-Biedl syndrome) involve disease-inherent hypoactivity of this same pathway upstream or downstream of MC4R; whether that disease state itself is associated with baseline gut dysbiosis, independent of setmelanotide, was not addressed by either source found and is not asserted here, consistent with this dossier's POMC/PCSK1 disease-state wall-off.
  • Counter-evidence on record: None found for a setmelanotide-specific harm direction. A third, tangentially related finding was located but not independently opened in full this session and is not cited as support: a 2025 NPJ Biofilms and Microbiomes paper (Bremard L et al., "Targeted proteomics reveal alpha-MSH-like Enterobacterial ClpB protein in gut microbiota of patients with anorexia nervosa") describes gut bacteria producing a protein that mimics alpha-MSH, the reverse causal direction (microbiome affecting the melanocortin system, not the drug affecting the microbiome); named here only to disclose that it was seen in the search, not used as evidence.

Regulatory status

Not a labeled finding. The current DailyMed label contains no microbiome-related content; the drug's own labeled gastrointestinal adverse reactions (nausea, diarrhea, vomiting, abdominal pain) are clinical outcomes, not microbiome measurements, and remain walled off from this entry per Hard Rule 2, as in the original review.

Population evidence

(1) Toledo M, Martinez-Martinez S, Van Hul M, Laudo B, Eyre E, et al. "Rapid modulation of gut microbiota composition by hypothalamic circuits in mice." Nature Metabolism, 2025. DOI 10.1038/s42255-025-01280-3. Directly opened and read this revision. Chemogenetic activation of hypothalamic POMC neurons in male mice (the neurons that synthesize the endogenous MC4R ligand alpha-MSH and whose downstream signaling setmelanotide is designed to reproduce) altered duodenal gut microbiota composition within 2 to 4 hours, mediated by increased duodenal sympathetic tone (elevated adrenaline, not noradrenaline) and transcriptomic reconfiguration of duodenal neuronal/synaptic pathways; POMC-neuron activation produced substantially larger microbiota effects than AgRP-neuron activation, and diet-induced obesity blunted the leptin-triggered version of this response. (2) Matsumoto M, Miura O, Moriya T, et al. "Cross-organ multi-omics profiling of microbiome and metabolome along the gut-liver axis in MASH model mice induced by western diet and MC4R knockout." Gut Pathogens, 2026. DOI 10.1186/s13099-026-00813-9. Directly opened and read this revision. MC4R-knockout mice fed a Western diet for 12 weeks developed intestinal dysbiosis (decreased protective taxa Muribaculaceae and Allobaculum; increased pro-inflammatory Desulfovibrionaceae and Bacteroides) alongside hepatic steatosis, inflammation, and fibrosis, with correlated bile-acid and lipid dysregulation across gut, liver, and plasma. Neither study used setmelanotide or any pharmacological MC4R agonist; both are mouse models, Tier B/C for setmelanotide specifically.

Mechanism

Two distinct, non-contradictory mechanisms at different points on the same pathway: acute sympathetic-nerve-mediated microbiota remodeling following POMC/MC4R-pathway activation (Toledo et al.), and chronic dysbiosis following complete, permanent loss of MC4R signaling under dietary challenge (Matsumoto et al.). Because setmelanotide is a sustained MC4R agonist, not a POMC-neuron chemogenetic activator or a receptor knockout, neither model maps directly onto its pharmacology; the honest reading is that MC4R-pathway signaling status is a real, mechanistically plausible modulator of gut microbiota composition, with the knockout data suggesting that restoring or engaging MC4R signaling (as setmelanotide does, in patients whose endogenous pathway is hypoactive due to POMC, PCSK1, LEPR, or BBS-related defects) is at least as likely to be neutral-to-protective as harmful, not a directional depletion risk.

Counter-evidence held on record

No gut microbiome change has ever been measured in a setmelanotide-treated patient. This entry exists because a fresh, dedicated search for the mechanistic gut-brain angle, specifically prompted by MC4R's known role in hypothalamic-gut signaling, located real animal literature that earlier attempts on this category missed; it is not a basis for probiotic, prebiotic, or any other microbiome-targeted supplementation, and the evidence found points at least as much toward a protective as a harmful direction for a signaling-restoring agonist.

  • Toledo M, Martinez-Martinez S, Van Hul M, Laudo B, Eyre E, et al. Rapid modulation of gut microbiota composition by hypothalamic circuits in mice. — Directly opened and read in full during the revision pass. Chemogenetic activation/inhibition of hypothalamic POMC or AgRP neurons, and central leptin/ghrelin, altered gut microbiota composition within 2 to 4 hours via increased duodenal sympathetic tone; POMC-neuron activation produced the largest effect. Primary support for the Gut microbiome risk entry (yellow). Mouse study; setmelanotide not in the cohort; cited as pathway-level (POMC/MC4R circuit) mechanistic evidence, not drug-specific data.
  • Matsumoto M, Miura O, Moriya T, Ogino H, Hirayama M, Mitsui A, Hirayama T, Ebisuno Y, Kaneko M, Satomi Y, Nio Y. Cross-organ multi-omics profiling of microbiome and metabolome along the gut-liver axis in MASH model mice induced by western diet and MC4R knockout. — Directly opened and read in full during the revision pass. MC4R-knockout mice fed a western diet for 12 weeks developed intestinal dysbiosis (decreased Muribaculaceae/Allobaculum, increased Desulfovibrionaceae/Bacteroides) and hepatic steatosis/fibrosis with correlated bile-acid and lipid dysregulation. Second support for the Gut microbiome risk entry (yellow), opposite (loss-of-function) direction from the Toledo et al. study above. Mouse genetic-knockout study; setmelanotide not in the cohort.

Oxygen and ATP Output

Oxygen delivery and ATP production are assessed separately. Nothing here is counted twice.

ATP production, drug's own intended increased-energy-expenditure mechanism

Yellow — Low

See study details

The regulatory label states, based on nonclinical (animal) evidence, that setmelanotide promotes weight loss "through decreased caloric intake and increased energy expenditure" via central MC4 receptor re-activation; this is the drug's own intended pharmacologic mechanism for treating obesity, not an energy-production deficit, and is graded yellow here only because the mandatory ATP production category requires an entry and this is the only setmelanotide-specific signal touching cellular/whole-body energy metabolism located in this review.

Full detail and limits

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. yellow

Limits on what this shows

  • Key negative/null findings: None located in the sources accessed this session.
  • At-risk subgroups: Not applicable; this is a population-wide intended pharmacologic effect, not a subgroup risk.
  • Counter-evidence on record: None found; not actively searched beyond the label and the blocked pivotal-trial attempts, given the entry's framing as intended pharmacology rather than an adverse deficit.

Regulatory status

IMCIVREE US PI, Section 12.1, Mechanism of Action: "Based on nonclinical evidence, setmelanotide may re-establish MC4 receptor pathway activity to reduce food intake and promote weight loss through decreased caloric intake and increased energy expenditure in patients with obesity due to acquired HO, BBS, or POMC, PCSK1, or LEPR deficiency associated with insufficient activation of the MC4 receptor."

Population evidence

Explicitly nonclinical (animal-model) evidence per the label's own wording; this review could not access the two pivotal human efficacy papers (Clement 2020, Haws 2020, both blocked to automated fetch, see Sources) to check whether either reported human indirect-calorimetry or resting-energy-expenditure data, which would be the appropriate human-level evidence for this category. This gap is disclosed rather than assumed away.

Mechanism

Named and drug-specific (central MC4 receptor agonism increasing sympathetically mediated energy expenditure), sourced directly from the regulatory label, Tier B strength given its nonclinical evidentiary basis as stated by the label itself.

Counter-evidence held on record

Per Hard Rule 2, this must never be read as an ATP-production deficiency. It is the drug working as intended, in the same direction as effective weight loss is supposed to work. No supplement or intervention aimed at "supporting ATP production" is indicated by this entry; it is included solely because this protocol requires the ATP production category to be evaluated and reported for every medication, graded or not.

Oxygen delivery / utilization

Not graded — disclosed evidence gap

See study details

No setmelanotide-specific or MC4R-pathway hemoglobin, hematocrit, red-cell-mass, or tissue-oxygen-delivery data were located after a renewed, multi-channel attempt, and no circulating consumer claim about setmelanotide and oxygen-carrying capacity or "energy"/anemia exists to rebut.

Full detail and limits

What the grade means here: Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result. ungraded

Limits on what this shows

  • Why no grade: Both conditions for ungraded are met, and this revision re-tested them directly rather than carrying the prior finding forward. (1) No Tier A/B/C evidence: the current DailyMed label was re-confirmed to contain no hemoglobin, hematocrit, or hematologic content of any kind beyond the sodium-specific warning graded above. This revision ran a direct PubMed search-listing query ("melanocortin erythropoietin OR hematocrit OR red blood cell") that returned results but none relevant to MC4R or setmelanotide (transfusion medicine, ectopic-hormone case reports, sickle-cell exchange transfusion), a dedicated PubMed query for "melanocortin 4 receptor hemoglobin erythropoiesis" that returned zero results outright, and two Crossref queries (melanocortin/hemoglobin/oxygen-delivery; alpha-MSH/erythropoiesis/red blood cell) that both returned only unrelated results (a liposome drug-delivery peer review, a 1976 salmon-hemoglobin dissertation, a general erythropoiesis-transporter dissertation with no melanocortin content). No mechanism connecting central or peripheral melanocortin signaling to erythropoiesis, hemoglobin synthesis, or tissue oxygen delivery was located in any source this revision could reach. (2) No circulating claim: see Fails verification.

Tooling disclosure

This revision's fresh attempt: PubMed's search-listing interface was reachable and returned genuine (if irrelevant) results for several queries this pass, an improvement over the original review's bot-verification blocks, and is the primary channel credited for this category's renewed, thorough search. Crossref was reachable for some queries and rate-limited (HTTP 429) on others. The Europe PMC REST API, Semantic Scholar API, and OpenAlex API remained unavailable this revision as well; the agent proxy's own status log recorded these specifically as gateway-level connect_rejected 403s (policy denial, not a simple rate limit) for www.ebi.ac.uk, api.semanticscholar.org, and api.openalex.org, indicating a standing, session-level restriction on these three hosts rather than a transient one. General WebSearch was unavailable throughout this revision (session-wide query budget already exhausted). Given a real, if narrower-than-ideal, set of working channels was used across multiple phrasings this pass with a consistent null result, this category is judged a genuine literature gap rather than a tooling artifact, though the persistent unavailability of Europe PMC, Semantic Scholar, and OpenAlex means it cannot be called an exhaustive search either.

All references used above
  1. IMCIVREE (setmelanotide) injection, US Prescribing Information, original approval label. — Full original label: metabolism, absorption, excretion, renal impairment, CYP interaction statement, adverse reaction tables (skin hyperpigmentation 78%, injection site reactions 96%, nausea 56%, headache 41%, diarrhea 37%, depression 26%, suicidal ideation 11%, spontaneous penile erection 23% in males), mechanism of action (Section 12.1, MC1-receptor melanin mechanism).
  2. IMCIVREE (setmelanotide) injection, US Prescribing Information, current label. — Current, expanded label covering the later-approved acquired hypothalamic obesity and expanded pediatric (age 2+) indications. Source for Section 5.5 (acute adrenal insufficiency, 5% vs. 0% placebo in acquired HO with pre-existing secondary adrenal insufficiency), Section 5.6 (sodium imbalance in concomitant central diabetes insipidus), Section 5.4 (skin exam/melanocytic nevi monitoring), Section 12.1 (nonclinical mechanism, "decreased caloric intake and increased energy expenditure"), and confirmation that no hemoglobin, hematocrit, iron, copper, or general electrolyte-panel content appears anywhere in the label.
  3. WHO Collaborating Centre for Drug Statistics Methodology. ATC/DDD Index, A08AA12 Setmelanotide. — Confirms ATC classification under A08AA, centrally acting antiobesity products, alongside phentermine, sibutramine, and related agents.
  4. Crossref API query, "setmelanotide." — Comprehensive index of setmelanotide's own academic publication record: 12 works including BNF/BNFc monographs, two CADTH health-technology-assessment reviews (Canadian Journal of Health Technologies, 2023), Markham A, "Setmelanotide: First Approval," Drugs 2021 (DOI 10.1007/s40265-021-01470-9), Kang C, "Setmelanotide in obesity: a profile of its use," Drugs & Therapy Perspectives 2022, and Haws R et al. 2020 (below). Used to confirm no setmelanotide-specific mitochondrial, oxidative-stress, iron, copper, or microbiome study exists in the indexed literature.
  5. Haws R, Brady S, Davis E, et al. Effect of setmelanotide, a melanocortin-4 receptor agonist, on obesity in Bardet-Biedl syndrome. — Pivotal BBS trial. Confirmed hybrid open access via Unpaywall (CC-BY-NC-ND, Wiley-hosted), but the PDF and landing-page URLs both returned HTTP 403 to automated fetch in this session and could not be opened; only the title, authors, and journal metadata (via Crossref and Unpaywall) are used here, not any content from the paper itself.Not independently opened this session; cited for bibliographic identification only, not as a source of extracted findings.
  6. Clement K, Fernandez-Marcos PJ, et al. Efficacy and safety of setmelanotide, an MC4R agonist, in individuals with severe obesity due to LEPR or POMC deficiency. — Pivotal POMC/LEPR deficiency trial. Confirmed closed-access with no open-access location via Unpaywall; the Elsevier/ScienceDirect landing page returned no readable content to automated fetch.Not opened this session in any form; cited for bibliographic identification only, not as a source of extracted findings.
  7. Unpaywall API queries for the DOIs above. — Used to check open-access availability before attempting full-text fetch; correctly identified the Lancet Diabetes & Endocrinology paper as closed access (is_oa: false) and the Diabetes Obes Metab paper as hybrid open access (is_oa: true), which was then attempted and blocked as noted above.
  8. Krude H, Biebermann H, Luck W, Horn R, Brabant G, Gruters A. Severe early-onset obesity, adrenal insufficiency and red hair pigmentation caused by POMC mutations in humans. — Landmark description (1,408 citations per Crossref metadata) establishing that POMC deficiency causes true ACTH/cortisol deficiency and red-hair/pale-skin pigmentation as inherent, disease-caused features, independent of any drug. Used solely for the Headline finding's disease-state confounding disclosure, not as evidence for any graded entry.Cohort is the genetic disease population, not a setmelanotide-treated cohort; used only to establish disease-inherent (not drug-caused) pathology, per this review's explicit mandate to distinguish the two.
  9. Bandsma RHJ, Sokollik C, Chami R, Cutz E, Brubaker PL, et al. From Diarrhea to Obesity in Prohormone Convertase 1/3 Deficiency. — Describes age-dependent malabsorptive diarrhea and enteroendocrine dysfunction as an inherent feature of PCSK1 (prohormone convertase 1/3) deficiency. Used solely for the Headline finding's disease-state confounding disclosure.Cohort is the genetic disease population, not a setmelanotide-treated cohort; used only to establish disease-inherent (not drug-caused) pathology.
  10. Aerts L, Terry NA, Sainath NN, Torres C, Martin MG, Ramos-Molina B, Creemers JW. Novel Homozygous Inactivating Mutation in the PCSK1 Gene in an Infant with Congenital Malabsorptive Diarrhea. — Confirms malabsorptive diarrhea and metabolic complications as characteristic, disease-inherent features of PCSK1 deficiency with variable intestinal morphology. Used solely for the Headline finding's disease-state confounding disclosure.Cohort is the genetic disease population, not a setmelanotide-treated cohort; used only to establish disease-inherent (not drug-caused) pathology.
  11. Wikipedia. Tyrosinase. — General enzymology reference, independently opened and read in full, confirming tyrosinase's binuclear type-3 copper active site and its rate-limiting role in melanin biosynthesis. Used as the general, non-drug-specific mechanistic basis for the Copper entry; not a setmelanotide-specific or even a peer-reviewed primary source, and disclosed as such in that entry.
  12. Crossref API query, melanocortin/MC4R crossed with iron, hepcidin, and ferroportin. — Eight results returned, all confirmed on title review to concern the hepcidin-ferroportin iron-homeostasis system alone with no melanocortin-pathway involvement; a clean negative result supporting the Iron entry's ungraded status.
  13. Crossref API query, melanocortin-4-receptor agonism and mitochondrial biogenesis/oxidative stress in brown adipose tissue. — Returned one tangentially relevant 2008 Faculty Opinions recommendation blurb (of a neuroanatomical MC4R-mRNA-expression paper, not a functional mitochondrial study) and otherwise unrelated results; not independently opened in full and not cited as support for any grade.Not opened and verified beyond the metadata/summary returned by the API; excluded from supporting any graded claim per this protocol's citation rule.
  14. Crossref API query, alpha-MSH/MC4R and oxidative stress, antioxidant activity, neuroprotection. — Returned only tangential results: an MC1-receptor (not MC4R) macrophage-immunology conference abstract (Taylor and Li, J Immunol 2007) and a non-peer-reviewed student-research-journal item on MC1R and Parkinson's disease. Neither opened in full nor cited as support.Not opened and verified beyond API-returned metadata; excluded from supporting any graded claim.
  15. Toledo M, Martinez-Martinez S, Van Hul M, Laudo B, Eyre E, et al. Rapid modulation of gut microbiota composition by hypothalamic circuits in mice. — Directly opened and read in full during the revision pass. Chemogenetic activation/inhibition of hypothalamic POMC or AgRP neurons, and central leptin/ghrelin, altered gut microbiota composition within 2 to 4 hours via increased duodenal sympathetic tone; POMC-neuron activation produced the largest effect. Primary support for the Gut microbiome risk entry (yellow). Mouse study; setmelanotide not in the cohort; cited as pathway-level (POMC/MC4R circuit) mechanistic evidence, not drug-specific data.
  16. Matsumoto M, Miura O, Moriya T, Ogino H, Hirayama M, Mitsui A, Hirayama T, Ebisuno Y, Kaneko M, Satomi Y, Nio Y. Cross-organ multi-omics profiling of microbiome and metabolome along the gut-liver axis in MASH model mice induced by western diet and MC4R knockout. — Directly opened and read in full during the revision pass. MC4R-knockout mice fed a western diet for 12 weeks developed intestinal dysbiosis (decreased Muribaculaceae/Allobaculum, increased Desulfovibrionaceae/Bacteroides) and hepatic steatosis/fibrosis with correlated bile-acid and lipid dysregulation. Second support for the Gut microbiome risk entry (yellow), opposite (loss-of-function) direction from the Toledo et al. study above. Mouse genetic-knockout study; setmelanotide not in the cohort.
  17. Quintanilla RA, Perez MJ, Aranguiz A, Tapia-Monsalves C, Mendez G. Activation of the Melanocortin-4 Receptor Prevents Oxidative Damage and Mitochondrial Dysfunction in Cultured Hippocampal Neurons Exposed to Ethanol. — Directly opened and read in full during the revision pass. The MC4R agonist RO27-3225 (250 nM, 1 hour pre-treatment) prevented ROS increase, mitochondrial membrane potential loss, and cytosolic calcium dysregulation, and increased ATP production and Nrf-2/NQO1 antioxidant-pathway activation, in cultured rat hippocampal neurons exposed to ethanol (50-75 mM, 24 h). Primary support for both the Mitochondrial burden and Oxidative stress entries (yellow, protective/reverse direction). Cell-culture study using RO27-3225, not setmelanotide; class extrapolation for this drug.
  18. Zhang HH, Liu J, Qin GJ, Li XL, Du PJ, Hao X, Zhao D, Tian T, Wu J, Yun M, Bai YH. Melanocortin 4 Receptor Activation Attenuates Mitochondrial Dysfunction in Skeletal Muscle of Diabetic Rats. — Identified and bibliographically confirmed via Crossref during the revision pass (title, authors, journal, volume/pages/DOI). Wiley-published; returned HTTP 403 to fetch and Unpaywall confirmed closed access with no open-access location.Not independently opened this session; title named for context only, not used to support any graded claim's content.
  19. Torres AK, Tapia-Rojas C, Cerpa W, Quintanilla RA. Stimulation of Melanocortin Receptor-4 (MC4R) Prevents Mitochondrial Damage Induced by Binge Ethanol Protocol in Adolescent Rat Hippocampus. — Identified and bibliographically confirmed via Crossref during the revision pass. Elsevier-published; returned no readable content to automated fetch and Unpaywall confirmed closed access with no open-access location.Not independently opened this session; title named for context only, not used to support any graded claim's content.
  20. PubMed search-listing pages, various queries (MC4R gut microbiome; MC4R agonist mitochondrial function; POMC neurons gut microbiota; melanocortin erythropoietin OR hematocrit OR red blood cell; melanocortin 4 receptor hemoglobin erythropoiesis). — Used to identify the Toledo, Matsumoto, Quintanilla, Zhang, and Torres papers above, and to confirm a genuine null result for Oxygen delivery/utilization. Intermittently accessible this pass (some queries returned real results, others returned an automated reCAPTCHA/bot-verification screen); each result set is disclosed as it was used.