Skip to main content
MyDeficiencies

Fluoxetine

Selective serotonin reuptake inhibitor (SSRI)

Also sold as Prozac, Sarafem, Selfemra.

Analyze another medication Medication directory

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.

Fluoxetine has no classical chelation, enzyme-induction, or renal-wasting depletion mechanism. It is a well-absorbed oral drug, extensively metabolized in the liver by demethylation to the active metabolite norfluoxetine, and it is itself a potent inhibitor (not an inducer) of CYP2D6, which means it does not accelerate the catabolism of any cofactor the way an enzyme-inducing anticonvulsant does. It is cleared almost entirely by hepatic metabolism to inactive metabolites excreted by the kidney, not by direct renal tubular handling of an electrolyte or mineral, and no gastric-pH, chelation, bile-acid, or transporter-competition mechanism is documented in its label. The one place fluoxetine's own pharmacology does directly and measurably touch a body chemical is water and sodium handling: like other SSRIs, it can trigger the syndrome of inappropriate antidiuretic hormone secretion (SIADH), producing a dilutional, not dietary, drop in serum sodium. That finding is graded red on two independent, drug-specific Tier A sources (the FDA label and a 2026 meta-analysis stratifying fluoxetine separately from the SSRI class), and it is explicitly framed as an excess/retention risk, not a deficiency, so the correct response is monitoring and medical management, never salt supplementation.

Selective serotonin reuptake inhibitor (SSRI) · ATC N06AB03 · also sold as Prozac and Sarafem and Selfemra and generic fluoxetine · reviewed 2026-09-29. 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 Fluoxetine 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

Sodium

Red — Severe

See study details

Fluoxetine can trigger the syndrome of inappropriate antidiuretic hormone secretion, causing water retention that dilutes serum sodium; this is a retention hazard from the drug's own pharmacology, not a dietary sodium deficiency, and correcting it is a medical task, never a supplementation one.

Full detail, limits and 1 references

What the grade means here: 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. red, excess/retention

Limits on what this shows

  • Key negative/null findings: None located that contradict the SIADH signal for fluoxetine specifically. The wide confidence interval on the fluoxetine-stratified pooled estimate (0.06 to 36.85%) reflects genuine between-study heterogeneity in a small number of stratified studies, not an absence of effect; it is reported here rather than rounded to a false-precision single figure.
  • At-risk subgroups: Older adults, especially older women; concomitant diuretic or other hyponatremia-associated drug use; low body weight; the first weeks of treatment, per the general SSRI-hyponatremia literature and the label's own framing.

Regulatory status

FDA labeling for Prozac carries an explicit hyponatremia/SIADH warning: cases with serum sodium below 110 mmol/L have been reported, generally reversible on discontinuation.

Population evidence

Zhang Y, Zhang J, Jing R, systematic review and meta-analysis, BMC Geriatrics, 2026 (DOI 10.1186/s12877-026-07911-y): 21 cohort studies, 2,115,187 elderly antidepressant users. Fluoxetine was stratified separately from the rest of the SSRI class across 4 studies, pooled event rate for any hyponatremia 13.00% (95% CI 0.06 to 36.85%, I 2 =87.25%, wide interval reflecting few studies and high heterogeneity). The overall SSRI class pooled rate across 17 studies was 9.81% for any hyponatremia (95% CI 6.04 to 14.31%) and 2.75% for clinically relevant hyponatremia across 8 studies (95% CI 0.47 to 6.67%), with SSRIs as a class showing a significantly increased risk versus non-users.

Mechanism

Named: SSRI-potentiated, non-osmotic release of antidiuretic hormone (SIADH), producing free-water retention and a dilutional, not a true, sodium deficit.

Counter-evidence held on record

Several fluoxetine-specific case reports and an elderly-cohort incidence study (Wilkinson et al 1999, British Journal of Clinical Pharmacology) were located describing this same effect, but could not be opened during this review (HTTP 403 on the publisher page) and are not used as evidentiary basis here; they are listed in Sources as found-but-inaccessible for a future revision to confirm and add. This is a water- and hormone-driven retention/dilution effect, not a body sodium (salt) deficiency, and it does not support sodium or electrolyte supplementation around fluoxetine use. Management is medical: baseline and early-treatment serum sodium checks in older adults, especially with concurrent diuretics; free-water restriction and prescriber involvement if hyponatremia develops; oral salt tablets are not an appropriate home response to SSRI-associated hyponatremia.

  • Zhang Y, Zhang J, Jing R. Risk of antidepressant-induced hyponatremia in geriatric patients: a systematic review and meta-analysis. — Systematic review/meta-analysis, 21 cohort studies, n=2,115,187 (Tier A, fluoxetine stratified separately across 4 of the included studies). Primary source for the Sodium entry's population evidence.

No category or classical nutrient was ungraded in this review

Not graded — disclosed evidence gap

See study details

Every one of the seven mandatory physiological categories reached at least a yellow grade on real, drug-specific or class-level Tier B/C evidence; this section is printed, per Hard Rule 1 and Hard Rule 8, to state plainly that the dual-condition ungraded test was checked for each category and did not apply, rather than silently omitting the section.

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. none

Limits on what this shows

  • Why no grade was withheld: Fluoxetine's decades-long, unusually deep literature base (in clinical use since 1987) meant a genuine multi-channel search located at least mechanistic (Tier B) or class-level (Tier C) evidence for every required category: gut microbiome risk, mitochondrial burden, oxidative stress, copper, iron, oxygen delivery/utilization, and ATP production. Where that evidence was thin or access-limited (Iron; the hematologic half of Oxygen delivery/utilization), it is graded yellow with the access limitation disclosed in the entry itself, per Hard Rule 8's instruction not to force a real gap into a falsely reassuring shape, rather than marked ungraded, since the dual condition (no Tier B/C evidence and no circulating claim) was not met for any category.

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

Yellow — Low

Evidence in: Tier B

In human cell lines exposed to fluoxetine concentrations roughly 25 to 200 times typical therapeutic plasma levels, the drug triggers mitochondrial calcium overload and necrotic cell death; whether this operates at ordinary oral dosing in living patients has not been shown.

Full detail, limits and 1 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, in vitro tier B

Limits on what this shows

  • Key negative/null findings: Effect magnitude is concentration-dependent and reported only at the 40 to 100 μM range, 25 to 200-fold above measured therapeutic plasma concentrations; the authors themselves flag this gap between the in vitro system and clinical dosing.
  • At-risk subgroups: None defined clinically. Theoretical relevance to overdose/toxicology settings rather than standard therapeutic dosing.

Regulatory status

Not addressed in labeling.

Population evidence

Charles E et al, "The antidepressant fluoxetine induces necrosis by energy depletion and mitochondrial calcium overload," Oncotarget, 2016, DOI 10.18632/oncotarget.13689, PMID 27911858. In vitro, human cell lines (Jurkat T-leukemic cells, peripheral blood lymphocytes, HeLa cells), fluoxetine 5 to 100 μM, primary effects reported at 40 to 100 μM. The authors explicitly state this exceeds therapeutic plasma levels of 0.5 to 1.6 μM.

Mechanism

Named: fluoxetine induces mitochondrial Ca 2+ accumulation via the mitochondrial calcium uniporter (MCU), producing calcium overload that triggers cell death, mainly necrosis and/or late apoptosis rather than early apoptosis.

Counter-evidence held on record

The concentration dependency is itself the principal limit on clinical extrapolation; no human or standard-dose animal study measuring mitochondrial structure/function after ordinary oral fluoxetine dosing was located. Do not present as evidence that standard-dose fluoxetine damages mitochondria in patients. The demonstrated effect requires concentrations well above what oral dosing produces.

  • Charles E, Hammadi M, Kischel P, et al. The antidepressant fluoxetine induces necrosis by energy depletion and mitochondrial calcium overload. — In vitro, human cell lines (Jurkat, peripheral blood lymphocytes, HeLa), 5 to 100 μM fluoxetine (Tier B, supraphysiologic concentration). Primary source for the Mitochondrial burden, ATP production, and Oxygen delivery/utilization entries; see Overlap map.

Oxidative Stress

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

Oxidative stress

Yellow — Low

Evidence in: Tier A, context flag

In a fluoxetine-specific human cohort, oxidative markers were elevated during acute depression and largely did not change significantly after three months of fluoxetine; total antioxidant status stayed reduced in both phases. This looks illness-linked rather than a fluoxetine effect, and the null changes are the most important finding to report.

Full detail, limits and 1 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, human tier A, context flag

Limits on what this shows

  • Key negative/null findings: MDA, SOD1, catalase, and GPx all showed no statistically significant fluoxetine-associated change; this is the central, explicitly disclosed null result of this entry and is the strongest available counter-evidence to any claim that fluoxetine itself worsens oxidative stress.
  • At-risk subgroups: None defined beyond the first-episode MDD population studied; whether TAS normalizes over a longer treatment course than 3 months was not addressed.

Regulatory status

Not addressed in labeling.

Population evidence

Galecki P, Szemraj J, Bienkiewicz M, Florkowski A, Galecka E, "Lipid peroxidation and antioxidant protection in patients during acute depressive episodes and in remission after fluoxetine treatment," Pharmacological Reports, 2009;61(3):436 to 447, DOI 10.1016/S1734-1140(09)70084-2. Human, first-episode MDD, n=50 patients versus n=30 healthy controls, fluoxetine 20 mg/day for 3 months. Malondialdehyde (lipid peroxidation) was significantly higher in acute depression than controls and did not change significantly after treatment. Superoxide dismutase (SOD1) and catalase were elevated acutely and unchanged after treatment. Glutathione peroxidase (GPx) did not differ significantly from controls at either timepoint. Total antioxidant status (TAS) was reduced versus controls during acute depression and remained reduced after clinical remission on fluoxetine.

Mechanism

Not a fluoxetine drug mechanism; per this project's confounding-by-indication rule, the marker abnormalities predate treatment and persist despite clinical response, consistent with an illness-associated redox imbalance rather than a drug-induced one.

Counter-evidence held on record

A related fluoxetine-plus-aspirin oxidative-stress study by the same research group (PubMed listing PMID 19319921) was located but could not be opened beyond page metadata during this review and is not used as evidence here. Do not present this as "fluoxetine causes oxidative stress." The data show a depression-associated redox imbalance that fluoxetine, over this study's 3-month course, neither clearly worsened nor fully corrected.

  • Galecki P, Szemraj J, Bienkiewicz M, Florkowski A, Galecka E. Lipid peroxidation and antioxidant protection in patients during acute depressive episodes and in remission after fluoxetine treatment. — Human, n=50 first-episode MDD patients vs. n=30 healthy controls, fluoxetine 20 mg/day x3 months (Tier A, drug-specific). Primary source for the Oxidative stress entry, including its central null findings on MDA, SOD1, catalase, and GPx.

Copper and Iron Balance

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

Copper

Yellow — Low

See study details

Chronic citalopram and imipramine lowered rat serum copper by about 14% in one study; fluoxetine was not among the drugs tested, so this is class extrapolation, not direct evidence for fluoxetine, and is capped at yellow per this project's rules regardless of how the class-level result looks.

Full detail, limits and 1 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, class extrapolation, tier C

Limits on what this shows

  • Key negative/null findings: Brain copper was explicitly unchanged by drug treatment in this study, arguing against a central-nervous-system copper-depletion mechanism for the drugs that were tested.
  • At-risk subgroups: Cannot be determined for fluoxetine; not tested.

Regulatory status

Not addressed in labeling.

Population evidence

Schlegel-Zawadzka M, Nowak G, "Alterations in serum and brain trace element levels after antidepressant treatment. Part II. Copper," Biological Trace Element Research, 2000;73(1):37 to 45, DOI 10.1385/BTER:73:1:37. Rat study; drugs tested were citalopram, imipramine, and electroconvulsive shock (ECS), not fluoxetine. Chronic citalopram and imipramine (not ECS) significantly decreased serum copper by approximately 14%. Brain copper was unaffected by any drug treatment; ECS alone raised hippocampal copper by 36% and cerebellar copper by 16%.

Mechanism

Not established for any drug in this study; the authors do not specify whether the serum copper decrease reflects altered ceruloplasmin synthesis, absorption, or renal handling.

Counter-evidence held on record

Per this project's cohort rule, fluoxetine's absence from this study's cohort caps it at Tier C for fluoxetine regardless of how rigorous the citalopram/imipramine findings are for those drugs. This is one class member's rat data, not a fluoxetine finding. It should not be presented to a consumer as evidence that fluoxetine itself lowers copper.

  • Schlegel-Zawadzka M, Nowak G. Alterations in serum and brain trace element levels after antidepressant treatment. Part II. Copper. — Rat study; citalopram, imipramine, and ECS tested (Tier C for fluoxetine, which was not in this cohort). Primary source for the Copper entry, explicitly marked as class extrapolation.Cohort excluded fluoxetine: citalopram, imipramine, and electroconvulsive shock were tested in rats, not fluoxetine; cited only as class-level context, capped at yellow per this project's cohort rule.

Iron

Yellow — Low

See study details

Two mechanistic papers name fluoxetine directly, not just its class, in connection with iron-transport biochemistry: binding to human transferrin, and endolysosomal iron dyshomeostasis induced by "weak base" drugs including fluoxetine; full texts could not be retrieved during this review, and no clinical study of fluoxetine's effect on iron or ferritin status was found at all.

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, mechanistic, limited access

Limits on what this shows

  • Key negative/null findings: None identified; not accessible at this depth.
  • At-risk subgroups: None characterized; no clinical data exists to define one.

Regulatory status

Not addressed in labeling.

Population evidence

None. A direct PubMed search for "fluoxetine iron status" returned zero results (confirmed via PubMed's own search-listing page, "No results were found"). A broader search for "fluoxetine AND (iron OR ferritin OR transferrin)" surfaced two fluoxetine-named mechanistic papers, "Elucidating the Interactions of Fluoxetine with Human Transferrin" (2022) and "Weak base drug-induced endolysosome iron dyshomeostasis" (2024, this paper's summary explicitly names fluoxetine among the drugs addressed), both accessible only at the PubMed search-listing title/snippet level; deeper access (full abstract, journal, DOI) was blocked on every channel attempted (see access notes).

Mechanism

Named only at snippet-confidence: fluoxetine reported to bind human transferrin, the iron-transport protein, in vitro, and to be grouped among weak-base drugs disrupting endolysosomal iron regulation. The direction and functional/clinical significance of either interaction could not be confirmed because full-text access was blocked throughout this review.

Counter-evidence held on record

This is the thinnest-evidenced entry in this dossier and rests on title/listing-level confirmation only. Restless-legs-syndrome literature linking SSRIs (including case reports naming other SSRIs) to a dopaminergic/iron-adjacent clinical outcome was also reviewed, but RLS is a clinical outcome, not a measured iron-status finding, and per this project's rules is not graded here as an iron entry. Treat this entry as a flag for re-review once full-text access is available, not as an established interaction; it should not be presented to a consumer as a confirmed iron effect.

Gut Microbiome Risk

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

Gut microbiome risk

Yellow — Low

Evidence in: Tier B

Fluoxetine itself, not just the SSRI class, has measurable antimicrobial activity against several gut bacterial species in vitro and measurably reshapes gut community structure in mice; no human microbiome study of fluoxetine was located, so the effect is real at the mechanistic level but unproven in people.

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, drug-specific tier B

Limits on what this shows

  • Key negative/null findings: In the Lyte 2019 mouse study, overall species richness and diversity indices did not differ significantly between fluoxetine and control groups; the effect was taxon-selective, not a global diversity collapse, and this null result is reported here rather than omitted.
  • At-risk subgroups: None characterized in humans. The mouse dose (20 mg/kg/day) is well above typical human weight-adjusted oral dosing, so whether the effect scales to ordinary therapeutic use in people is unknown.

Regulatory status

Not addressed in FDA/DailyMed labeling.

Population evidence

In vitro (Rukavishnikov G et al, Frontiers in Behavioral Neuroscience, 2023, DOI 10.3389/fnbeh.2023.1132127): fluoxetine at 200 μg/mL reduced growth rates of Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus by 6.9, 4.7, and 3.7 fold respectively versus control, with the least effect on Candida albicans, tested against 6 organisms including Bifidobacterium bifidum and Lactobacillus rhamnosus. In vivo (Lyte M, Daniels KM, Schmitz-Esser S, PeerJ, 2019, DOI 10.7717/peerj.6199): CF-1 male mice, n=10 per group, fluoxetine 20 mg/kg/day orally for 29 days; Lactobacillus johnsonii decreased 7.4-fold and the Bacteroidales S24-7 group decreased, while Alistipes, Lachnoclostridium, Anaerotruncus, and several Lachnospiraceae taxa increased.

Mechanism

Named: direct antimicrobial/growth-rate-inhibiting action, proposed by Lyte et al as operating through a microbial-endocrinology pathway (bacterial biogenic-amine transporters), rather than an indirect gut-conditions effect.

Counter-evidence held on record

The diversity-index null finding above is the main counter-evidence limiting this to a taxon-selective, not wholesale, effect. A PubMed search specifically for fluoxetine and human gut microbiota returned only in vitro and animal studies; no human clinical study of fluoxetine's microbiome effect was located. Real and drug-specific, but animal/in vitro evidence only. Do not present to consumers as an established human gut-health risk with a known effect size; frame as an active, mechanistically supported research question.

  • Lyte M, Daniels KM, Schmitz-Esser S. Fluoxetine-induced alteration of murine gut microbial community structure: evidence for a microbial endocrinology-based mechanism of action responsible for fluoxetine-induced side effects. — In vivo, CF-1 male mice, n=10/group, fluoxetine 20 mg/kg/day x29 days (Tier B, drug-specific). Primary source for the Gut microbiome risk entry's in vivo evidence, including the diversity-index null finding.
  • Rukavishnikov G, Leonova L, Kasyanov E, Leonov V, Neznanov N, Mazo G. Antimicrobial activity of antidepressants on normal gut microbiota: results of the in vitro study. — In vitro, 6 antidepressants (including fluoxetine) x 6 bacterial/fungal species (Tier B, drug-specific). Primary source for the Gut microbiome risk entry's in vitro growth-inhibition data.

Oxygen and ATP Output

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

ATP production

Yellow — Low

Evidence in: Tier B

The same human cell-line study that shows fluoxetine's mitochondrial calcium effect also shows a real drop in cellular ATP at high concentrations, roughly one third of the reduction produced by oligomycin, a direct ATP-synthase inhibitor; this is the same experimental system as the Mitochondrial burden and Oxygen delivery/utilization entries, not an independent replication (see Overlap map).

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, in vitro tier B

Limits on what this shows

  • Key negative/null findings: Same supraphysiologic-concentration caveat as the Mitochondrial burden entry; no lower-concentration or standard-dose data point was reported in this source.
  • At-risk subgroups: None defined clinically; same overdose/toxicology-relevance caveat as above.

Regulatory status

Not addressed in labeling.

Population evidence

Charles E et al, Oncotarget, 2016 (same source as Mitochondrial burden entry above). In HeLa cells, fluoxetine (40 to 100 μM) reduced ATP levels by an amount the authors describe as approximately one third of the decrease produced by oligomycin, a potent mitochondrial ATP-synthase inhibitor used as a reference comparator.

Mechanism

Named: downstream of the same mitochondrial calcium overload and impaired oxygen consumption described in the Mitochondrial burden entry; ATP depletion is presented by the authors as part of the same necrosis-inducing cascade, not a separate independent pathway.

Counter-evidence held on record

This ATP finding is one endpoint of the single Charles et al 2016 experimental system; see the Overlap map for how it relates to the Mitochondrial burden and Oxygen delivery/utilization entries. Do not present as evidence that standard-dose fluoxetine lowers cellular energy output in patients; the finding is specific to supraphysiologic in vitro exposure.

Oxygen delivery/utilization

Yellow — Low

Evidence in: Tier B

The same Charles et al 2016 human cell-line study shows fluoxetine inhibiting cellular oxygen consumption alongside its calcium and ATP effects; this speaks to cellular oxygen utilization, not to oxygen-carrying capacity (hemoglobin/hematocrit), for which no verified fluoxetine-specific source could be opened during this review.

Full detail, limits and 1 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, in vitro tier B

Limits on what this shows

  • Key negative/null findings: Same supraphysiologic-concentration caveat as the related entries above.
  • At-risk subgroups: None defined clinically.

Regulatory status

Not addressed in labeling.

Population evidence

Charles E et al, Oncotarget, 2016 (same source as above): fluoxetine (40 to 100 μM) inhibited oxygen consumption in HeLa cells, reported alongside the ATP and calcium findings above. No separate hemoglobin, hematocrit, or red-cell-mass source could be confirmed for fluoxetine specifically; a rat study titled "Citalopram and fluoxetine affects blood chemistry, hematology and brain serotonin in rats" (PubMed listing, PMID 24579503) was located but could not be opened despite repeated attempts across PubMed direct-fetch, Europe PMC, Semantic Scholar, and Crossref (all blocked, see access notes), so its findings are not used as evidence here.

Mechanism

Named for cellular oxygen utilization: impaired mitochondrial oxygen consumption as part of the same calcium-overload cascade described in the Mitochondrial burden entry. No mechanism confirmed for oxygen-carrying/hematologic capacity.

Counter-evidence held on record

This entry is deliberately narrower than "oxygen delivery": it grades cellular oxygen utilization (Tier B, supraphysiologic), not systemic oxygen-carrying capacity, which remains an access-limited gap disclosed here rather than papered over. Do not present as evidence that fluoxetine reduces blood oxygen-carrying capacity or causes anemia; that specific question remains unverified pending access to the blocked rat hematology source.

  • "Citalopram and fluoxetine affects blood chemistry, hematology and brain serotonin in rats." PMID 24579503.Found via search; blocked on repeated attempts (PubMed reCAPTCHA, Europe PMC HTTP 429, Semantic Scholar HTTP 429, Crossref HTTP 429); relevant to the hematologic-capacity half of the Oxygen delivery/utilization entry but not used as evidentiary basis there; flagged for re-check in a future revision.

Claims checked and not supported

These circulate online for this medication. They are listed here only so they can be answered, never as findings, and they are not graded.

A claim with no supporting evidence is not necessarily disproven. Where evidence actually argues against a claim, that is stated below.

  • Folate (vitamin B9)

    Where it comes from: Consumer drug-nutrient-depletion sites (for example, a pharmacy-wellness blog stating "folic acid depletion has been associated with SSRIs," and a broader site claiming "all SSRIs deplete B6, folate, and B12")

    Why it fails: The only fluoxetine-specific human study measuring folate (Papakostas GI et al, Int J Neuropsychopharmacol, 2005;8(4):523 to 528, DOI 10.1017/S1461145705005195, PMID 15877935, n=110) measured it at baseline, before fluoxetine exposure, as a predictor of how fast patients would respond (low folate predicted roughly 1.5 weeks' delayed improvement, p=0.0028), not as a before/after measure of drug-induced change. No fluoxetine-in-cohort study located shows folate declining on treatment. The literature instead runs the opposite direction: a randomized, placebo-controlled trial (Coppen and Bailey 2000, discussed secondhand in an NCBI Bookshelf FolATED review, NBK262310, since the primary Journal of Affective Disorders paper could not be opened directly) found adding 400 μg folic acid to fluoxetine improved response rates in women (82% versus 62% on placebo), consistent with baseline folate status predicting response, not fluoxetine consuming folate.

  • Vitamin B12

    Where it comes from: Same consumer sources, bundled with folate and B6 as "SSRIs deplete B6, folate, and B12"

    Why it fails: The same Papakostas 2005 study measured B12 only at baseline as a non-significant covariate of treatment response, not as a before/after measure. No fluoxetine-in-cohort study locating a B12 decline on treatment was found. B12 absorption depends on intrinsic factor and ileal transport, a pathway unrelated to fluoxetine's hepatic CYP2D6-mediated metabolism, so no plausible mechanism was identified either.

  • Vitamin B6

    Where it comes from: Consumer source stating "over 30% of patients on SSRIs have deficient B6 levels"

    Why it fails: No fluoxetine-specific or even class-stratified primary source could be located to support this statistic. The B6 literature actually located concerned B6 tested as an independent antidepressant in animal models, and B6 co-administration studies with other antidepressants, neither of which is evidence that fluoxetine depletes B6. The claimed statistic could not be traced to a citable primary source.

  • Magnesium

    Where it comes from: Consumer source naming "fluoxetine, paroxetine, sertraline, citalopram, escitalopram, and venlafaxine" as magnesium-depleting

    Why it fails: The magnesium-fluoxetine literature located runs entirely in the opposite direction: open-label and controlled augmentation studies adding magnesium to fluoxetine to improve depression and cognitive outcomes, which implies magnesium status may affect response, not that fluoxetine lowers magnesium. No renal-wasting, GI-malabsorption, or other depletion mechanism has been documented for fluoxetine specifically.

All references used above
  1. DailyMed. PROZAC (fluoxetine hydrochloride) capsule, Eli Lilly and Company, SPL. — FDA label (Tier A). Source for Clinical Pharmacology (metabolism, CYP2D6/CYP3A4 effects, absorption, elimination, half-life), Warnings and Precautions (SIADH/hyponatremia statement), Use in Specific Populations (hepatic/renal impairment dosing), and Drug Interactions (MAOIs, thioridazine, lithium, NSAIDs/warfarin).
  2. Zhang Y, Zhang J, Jing R. Risk of antidepressant-induced hyponatremia in geriatric patients: a systematic review and meta-analysis. — Systematic review/meta-analysis, 21 cohort studies, n=2,115,187 (Tier A, fluoxetine stratified separately across 4 of the included studies). Primary source for the Sodium entry's population evidence.
  3. Lyte M, Daniels KM, Schmitz-Esser S. Fluoxetine-induced alteration of murine gut microbial community structure: evidence for a microbial endocrinology-based mechanism of action responsible for fluoxetine-induced side effects. — In vivo, CF-1 male mice, n=10/group, fluoxetine 20 mg/kg/day x29 days (Tier B, drug-specific). Primary source for the Gut microbiome risk entry's in vivo evidence, including the diversity-index null finding.
  4. Rukavishnikov G, Leonova L, Kasyanov E, Leonov V, Neznanov N, Mazo G. Antimicrobial activity of antidepressants on normal gut microbiota: results of the in vitro study. — In vitro, 6 antidepressants (including fluoxetine) x 6 bacterial/fungal species (Tier B, drug-specific). Primary source for the Gut microbiome risk entry's in vitro growth-inhibition data.
  5. Charles E, Hammadi M, Kischel P, et al. The antidepressant fluoxetine induces necrosis by energy depletion and mitochondrial calcium overload. — In vitro, human cell lines (Jurkat, peripheral blood lymphocytes, HeLa), 5 to 100 μM fluoxetine (Tier B, supraphysiologic concentration). Primary source for the Mitochondrial burden, ATP production, and Oxygen delivery/utilization entries; see Overlap map.
  6. Schlegel-Zawadzka M, Nowak G. Alterations in serum and brain trace element levels after antidepressant treatment. Part II. Copper. — Rat study; citalopram, imipramine, and ECS tested (Tier C for fluoxetine, which was not in this cohort). Primary source for the Copper entry, explicitly marked as class extrapolation.Cohort excluded fluoxetine: citalopram, imipramine, and electroconvulsive shock were tested in rats, not fluoxetine; cited only as class-level context, capped at yellow per this project's cohort rule.
  7. Galecki P, Szemraj J, Bienkiewicz M, Florkowski A, Galecka E. Lipid peroxidation and antioxidant protection in patients during acute depressive episodes and in remission after fluoxetine treatment. — Human, n=50 first-episode MDD patients vs. n=30 healthy controls, fluoxetine 20 mg/day x3 months (Tier A, drug-specific). Primary source for the Oxidative stress entry, including its central null findings on MDA, SOD1, catalase, and GPx.
  8. Papakostas GI, Petersen T, Lebowitz BD, et al. The relationship between serum folate, vitamin B12, and homocysteine levels in major depressive disorder and the timing of improvement with fluoxetine. — Human, n=110 fluoxetine responders, baseline-only nutrient measures (Tier A, drug-specific). Central source for the Fails verification rebuttal of the folate/B12 depletion claims: low baseline folate predicted delayed response (about 1.5 weeks, p=0.0028), which is a pre-treatment predictor, not a measure of drug-induced change.
  9. National Institute for Health and Care Excellence (secondary discussion). Folate Augmentation of Treatment, Evaluation for Depression (FolATED): randomised trial and economic evaluation, Discussion chapter, discussing Coppen A and Bailey J, 2000, Journal of Affective Disorders. — Secondary source describing the Coppen and Bailey 2000 randomized, placebo-controlled folic-acid-augmentation-of-fluoxetine trial (400 μg folic acid, 82% vs. 62% response rate in women). Used in Fails verification (Folate) to establish the reverse causal direction.The primary Coppen and Bailey 2000 paper (Journal of Affective Disorders, DOI 10.1016/S0165-0327(00)00153-1) could not itself be opened during this review (Google reCAPTCHA on PubMed and PMC, HTTP 403 on ScienceDirect, HTTP 429 on Europe PMC, Semantic Scholar, and OpenAlex); this secondary NCBI Bookshelf source is cited instead and the primary paper is not independently cited.
  10. Wikipedia. Fluoxetine. — Used only for identity facts (ATC code N06AB03, brand names Prozac/Sarafem/Selfemra). Not used as evidence for any graded claim.
  11. PubMed search-listing pages, queries "fluoxetine iron status" (zero results) and "fluoxetine AND (iron OR ferritin OR transferrin)." — Surfaced the titles "Elucidating the Interactions of Fluoxetine with Human Transferrin" (2022) and "Weak base drug-induced endolysosome iron dyshomeostasis" (2024, names fluoxetine directly), used at snippet-confidence only in the Iron entry.Deeper access to both papers (full abstract, journal, DOI) was blocked on every channel attempted: direct PubMed article pages returned a Google reCAPTCHA challenge; the Europe PMC REST API, Semantic Scholar Graph API, Crossref API, and OpenAlex API each returned HTTP 429 on every attempt. Cited at title/listing-snippet level only.
  12. Wilkinson R, et al. Incidence and risk factors for hyponatraemia following treatment with fluoxetine or paroxetine in elderly people.Found via search; full text blocked (HTTP 403 at bpspubs.onlinelibrary.wiley.com); not used as evidentiary basis for the Sodium entry's grade, which rests instead on the DailyMed label and the 2026 BMC Geriatrics meta-analysis above.
  13. Cussotto S, et al. Differential effects of psychotropic drugs on microbiome composition and gastrointestinal function.Found via search; full text blocked (HTTP 429 on Europe PMC, repeated PubMed reCAPTCHA); not used as evidentiary basis for the Gut microbiome risk entry, which rests instead on Lyte 2019 and Rukavishnikov 2023 above.
  14. "Effect of fluoxetine treatment on mitochondrial bioenergetics in central and peripheral rat tissues." Applied Physiology, Nutrition, and Metabolism, 2015. PMID 25923579.Found via search; full text blocked (HTTP 403 at cdnsciencepub.com, HTTP 429 on Europe PMC retry); not used as evidentiary basis for the Mitochondrial burden entry, which rests instead on Charles et al 2016 above.
  15. "Citalopram and fluoxetine affects blood chemistry, hematology and brain serotonin in rats." PMID 24579503.Found via search; blocked on repeated attempts (PubMed reCAPTCHA, Europe PMC HTTP 429, Semantic Scholar HTTP 429, Crossref HTTP 429); relevant to the hematologic-capacity half of the Oxygen delivery/utilization entry but not used as evidentiary basis there; flagged for re-check in a future revision.
  16. Oliveira MT, et al. Fluoxetine and the mitochondria: a review of the toxicological aspects.Found via search; full text blocked (Google reCAPTCHA on both PubMed and ScienceDirect); not used as evidentiary basis for the Mitochondrial burden entry.
  17. Europe PMC REST API, Semantic Scholar Graph API, Crossref API, and OpenAlex API, multiple queries across this review.Returned HTTP 429 (rate limited) on essentially every attempt throughout this review and could not be used as a reliable channel; disclosed wherever it affected a specific entry above. PubMed's own search-listing pages (as opposed to individual PubMed article pages, which intermittently returned a Google reCAPTCHA challenge) remained the most reliable channel throughout and were used for source discovery and cohort screening.