Suvorexant

Limits on what this shows

• Null/negative findings: No human mitochondrial-function data for suvorexant were located in this review. Effect sizes and statistical values for the fission/fusion protein changes were not available in the retrievable abstract-level summary of this study.
• At-risk subgroups: None established in humans; applicability is limited to a specific chronic-stress/PTSD-like disease model in rats, not to typical suvorexant users being treated for insomnia without PTSD.

Regulatory status

Not addressed in the FDA label.

Population evidence

Prajapati SK, Ahmed S, Rai V, Gupta SC, Krishnamurthy S, J Affect Disord 2024, PMID 38185385: in vivo rat stress-re-stress (SRS) PTSD-like-symptom model, suvorexant administered alone and in combination with rapamycin (an mTOR inhibitor). Measured fission-regulating proteins (dynamin-related protein-1, mitochondrial-fission-protein-1) and fusion-regulating proteins (optic-atrophy-1, mitofusin-2), plus transmission electron microscopy of mitochondrial morphology. Suvorexant reduced fission-protein expression and restored fusion-protein expression, with a more pronounced effect in combination with rapamycin. Tier B, mechanistic animal study, this medication specifically.

Mechanism

Proposed via normalization of orexinergic and mTOR signaling in a chronic-stress model, reducing stress-induced mitochondrial fragmentation.

Counter-evidence held on record

This is not evidence of mitochondrial harm from suvorexant, but a single animal, disease-model study is also not strong enough to support a mitochondrial-support marketing claim for general users. It should not be generalized beyond the stress-model context it was measured in.

Limits on what this shows

• Why no grade: Both conditions for ungraded are met on the evidence actually retrieved: no Tier B or Tier C evidence was found to support even a yellow grade, and no circulating consumer claim specific to suvorexant and oxidative stress or antioxidant depletion was found on the sources checked (see Fails verification section). A later revision should re-attempt direct PubMed and Europe PMC querying once proxy access allows, before this is treated as a fully closed gap.

Channels tried

WebSearch, multiple separately phrased queries: "suvorexant mitochondria oxidative stress," "suvorexant 'oxidative stress' rat OR mice antioxidant," "suvorexant antioxidant glutathione superoxide dismutase malondialdehyde," "orexin antagonist 'oxidative stress' biomarkers." These returned the Prajapati et al. 2024 PTSD-model paper (which measures structural mitochondrial fission/fusion proteins, not redox/oxidative-stress markers such as glutathione, SOD, catalase, or malondialdehyde, and is graded separately under Mitochondrial burden) and otherwise returned only unrelated general oxidative-stress literature with no suvorexant content. A direct PubMed search-listing fetch for suvorexant and oxidative stress could not be completed: the outbound proxy returned HTTP 429 (rate-limited) on the attempt. Europe PMC REST API, Semantic Scholar API, and OpenAlex API calls were each rejected with HTTP 429 during this review and could not be used as independent channels for this term. DailyMed/FDA label (reviewed in full) does not address oxidative stress or redox markers.

Outcome

No suvorexant-specific or defensible class-level (orexin-antagonist-class) redox-marker study was found on the channels that did return results; the PubMed, Europe PMC, Semantic Scholar, and OpenAlex API channels for this specific term were blocked by rate-limiting rather than returning a confirmed clean negative, so this is disclosed as a possible tooling-access limitation layered on a genuine apparent literature gap, not a fully closed negative.

Limits on what this shows

• Why no grade: Both conditions for ungraded are met on the evidence actually retrieved: no Tier B or Tier C evidence exists to support even a yellow grade (no mechanism, no drug-specific or class-level study located), and no circulating consumer claim specific to suvorexant and copper was found. Treated as a genuine evidence gap, with a disclosed tooling limitation on the API channels flagged for a later revision.

Channels tried

WebSearch, multiple separately phrased queries: "suvorexant nutrient depletion vitamin mineral deficiency," "suvorexant copper zinc mineral levels study," "suvorexant copper ceruloplasmin trace element." None returned a suvorexant-specific or orexin-receptor-antagonist-class copper study; results were limited to unrelated general copper-biology and copper-and-sleep-condition (not copper-and-this-drug) content. A direct PubMed search-listing fetch for "suvorexant copper" was attempted but rejected with HTTP 429 by the outbound proxy before it could complete. Europe PMC REST API, Semantic Scholar API, and OpenAlex API (works-search) calls for this term were each rejected with HTTP 429. No mechanism from Step 1/2 (no chelation, no documented copper-transporter interaction) supports even a theoretical link. Consumer sources checked: general "drug mugger"/nutrient-depletion phrasing search, and a direct search for Suzy Cohen's "Drug Muggers" content paired with suvorexant/Belsomra/orexin; none found.

Outcome

Clean negative on the WebSearch-indexed sweep (multiple phrasings, genuinely completed, not a single blocked attempt); the PubMed, Europe PMC, Semantic Scholar, and OpenAlex API channels for this specific term were blocked by rate-limiting rather than independently confirming the negative, and should be re-attempted in a later revision.

Limits on what this shows

• Why no grade: Both conditions for ungraded are met: no Tier B or Tier C evidence exists (confirmed zero-result PubMed search, no chelation/absorption mechanism, no interaction-checker signal), and no circulating consumer claim specific to suvorexant and iron was found.

Channels tried

PubMed search-listing page, query "suvorexant iron," fetched directly via WebFetch: the page explicitly stated "No results were found," with no automatic term mapping applied, a clean zero-result response, not a block page, retrieved before the outbound proxy began rate-limiting PubMed and other hosts later in this review. WebSearch, query "suvorexant nutrient depletion vitamin mineral deficiency," returned no suvorexant-specific iron content. Drugs.com drug-interaction checker, Belsomra plus ferric citrate: returned "No drug interactions found," with the only listed warnings being generic, separate per-drug cautions unrelated to each other (hemochromatosis for ferric citrate, standard CNS/food cautions for Belsomra). Europe PMC REST API and OpenAlex API calls attempted for this term later in the review were rejected with HTTP 429. DailyMed/FDA label (reviewed in full) does not address iron status.

Outcome

Confirmed clean negative on the one channel that returned a genuine result (PubMed, explicit zero-result page), corroborated by a negative drug-interaction-checker result and by the absence of any absorption-interference mechanism in Step 1/2. This is the most confidently closed of the three ungraded entries in this dossier.

Limits on what this shows

• Null/negative findings: No suvorexant-specific microbiome study was located across the channels tried for this review (see the Ungraded disclosure notes below for method). The lemborexant study itself was uncontrolled (single-arm, no placebo group, no suvorexant comparator), so causality versus the passage of time or insomnia itself cannot be separated, and alpha diversity (Shannon's, Simpson's) was not reported as significantly changed, a partial null worth preserving alongside the beta-diversity and taxa-level findings.
• At-risk subgroups: None established for suvorexant specifically; the only direct human evidence is in lemborexant-treated insomnia patients.

Regulatory status

Not addressed in the suvorexant FDA label; no microbiome-related warning or monitoring requirement.

Population evidence

Miyata S, Iwamoto K, Okada I, et al., Nat Sci Sleep 2025, DOI 10.2147/NSS.S526037: open-label, single-arm, single-center pilot study, n=27 completers (29 enrolled), lemborexant 5 mg titrated to 10 mg in 10 participants, 12 weeks, with 16S rRNA sequencing and short-chain fatty acid measurement at baseline, week 4, and week 12. Firmicutes/Bacteroidetes ratio significantly higher at week 12 versus baseline (p less than 0.05); beta diversity by Jaccard dissimilarity significantly increased at week 12 (p less than 0.05); Parabacteroides significantly decreased at week 12 (p=0.0001, q less than 0.0001, Cohen's d=0.53); Akkermansia showed a strong negative correlation with sleep efficiency (r=-0.754, p=0.0003). This drug is lemborexant, not suvorexant; the cohort test for suvorexant specifically fails. Lemborexant (ATC N05CJ02) is a defensible class member under Hard Rule 6, sharing suvorexant's exact mechanism (dual orexin receptor antagonism), so this is labeled class extrapolation rather than drug-specific evidence.

Mechanism

Proposed via altered sleep architecture and circadian signaling affecting the gut-brain-microbiome axis, a mechanism that is class-plausible for any dual orexin receptor antagonist but not confirmed drug-specific for suvorexant.

Counter-evidence held on record

Theoretical and class-level only; no suvorexant-specific gut-health claim is established, and no probiotic or dietary-change recommendation is indicated by this evidence. The source study was also uncontrolled, so even its lemborexant-specific finding should be read cautiously.

Limits on what this shows

• Null/negative findings: Oxygen saturation itself (the actual oxygen-delivery parameter) was not significantly affected in either fully detailed OSA trial, at both a supratherapeutic dose in mild-moderate disease and a near-therapeutic single dose in severe disease, despite each trial being specifically designed and powered to detect respiratory worsening. The Respir Med 2015 COPD trial (PMID 25661282) and the Uemura 2015 healthy-subjects trial could not be read in full this review: the COPD-trial publisher page returned repeated HTTP 429 responses on every retry attempt, and the Uemura trial's Wiley host page returned HTTP 403; both are confirmed as real, drug-specific, peer-reviewed sources by title and indexing, but their numeric results are not independently verified here.
• At-risk subgroups: Severe OSA and severe COPD are explicitly not covered by an efficacy/safety trial in the FDA label's own framing (the Mieno 2025 severe-OSA trial is a single, non-randomized, open, single-dose study, not the pivotal trial the label refers to); the label advises clinician judgment for these groups accordingly.

Regulatory status

FDA label states BELSOMRA "has not been studied in patients with severe obstructive sleep apnea (OSA) or severe chronic obstructive pulmonary disease (COPD)" and advises clinical judgment in patients with compromised respiratory function; there is no boxed warning for respiratory depression.

Population evidence

Sun H et al., J Clin Sleep Med 2016, DOI 10.5664/jcsm.5382: randomized, double-blind, placebo-controlled crossover, n=26, mild-to-moderate OSA (AHI 5 to less than 30), suvorexant 40 mg (twice the maximum approved insomnia dose). Multi-dose apnea-hypopnea index (AHI) increased by a mean of 2.66 events/hour (90% CI 0.22 to 5.09); single-dose AHI difference -0.47 (95% CI -3.20 to 2.26). SpO2 showed no treatment effect on day 1 or day 4. Authors concluded no clinically important respiratory effect at this supratherapeutic dose. Mieno Y, Hayashi M, Souma T, et al., Sleep Biol Rhythms 2025, DOI 10.1007/s41105-024-00548-7: prospective, two-night polysomnography study, n=30 completers, severe OSA (median baseline AHI 41.6), suvorexant 15 mg single dose. AHI change +1.87 events/hour (95% CI -2.24 to 5.99, p=0.36, not statistically significant, though the upper confidence bound exceeded 5); mean apnea duration significantly prolonged by 1.97 seconds (p=0.031); oxygenation parameters (lowest SpO2, 3% oxygen desaturation index, time below 90% SpO2) showed no significant difference between nights. Two further drug-specific human respiratory studies were identified but could not be fully detailed this review (see Null/negative findings and Sources): Sun H et al., Respir Med 2015, PMID 25661282, in patients with chronic obstructive pulmonary disease; and Uemura N et al., J Clin Pharmacol 2015, DOI 10.1002/jcph.523, in healthy subjects.

Mechanism

CNS-depressant/sedative-hypnotic blunting of arousal response and possibly ventilatory drive during sleep, a mechanism class-associated with hypnotics generally and tested directly for suvorexant in the two fully detailed trials above.

Counter-evidence held on record

This is a drug-mechanism and safety-monitoring item, per this protocol's rule against relabeling a drug's own pharmacodynamic profile as a deficiency, not a nutrient-pathway oxygen-delivery deficiency. Nothing here implies a supplement, iron, or hemoglobin-building intervention is indicated. Patients with severe OSA or severe COPD should use suvorexant only under clinician guidance, given the absence of a dedicated severe-population efficacy/safety trial.

Limits on what this shows

• Null/negative findings: No significant change in total energy expenditure, meaning overall ATP-generating output was essentially unchanged even as the fuel source shifted. A separate Tier A human RCT in people with poorly controlled type 2 diabetes (Winkelman JW et al., Nat Sci Sleep 2023;15:1117-1128, DOI 10.2147/NSS.S434058, n=65-69, suvorexant 10-20 mg, 12 weeks) found no significant between-group difference in HbA1c, a relevant glycemic-control null finding. A Tier B mouse study (Tsuneki H et al., Endocrinology 2016;157(11):4146, DOI 10.1210/en.2016-1404, db/db diabetic mice, suvorexant 30 mg/kg resting-phase dosing for 2-4 weeks) found improved glucose tolerance without affecting body weight, food intake, or insulin sensitivity; this is included as supportive but indirect context (glycemic regulation, not a direct ATP-synthesis measurement) and is not used alone to support this entry's grade.
• At-risk subgroups: None identified; the human finding was observed in healthy men only (n=14), a single night of dosing, and has not been replicated or studied in women, older adults, or with chronic dosing.

Regulatory status

Not addressed in the FDA label; serum cholesterol showed a small dose-related increase in clinical trials (1 mg/dL at 10 mg to 6 mg/dL at 80 mg after 4 weeks, versus a 4 mg/dL decrease with placebo), a labeled lipid finding noted here for context but not graded as a classical-nutrient or Step-3-category entry.

Population evidence

Park et al. (Park, Yoshitake, Kioka, Ishihara, Yajima, Kawana, Kokubo, Matsuzaki, Kanbayashi, Yanagisawa, Tokuyama), iScience 2024;27(7):110212, DOI 10.1016/j.isci.2024.110212, PMID 38993665: randomized, double-blind, placebo-controlled, crossover, n=14 healthy men, suvorexant 20 mg. Fat oxidation during sleep increased, with the effect persisting after waking the next morning; protein catabolism decreased; total energy expenditure was not significantly affected; REM sleep increased while N1 stage decreased. Tier A, drug-specific, this medication in the cohort.

Mechanism

Orexin signaling normally promotes wakefulness-linked catabolic and thermogenic activity; antagonism during the sleep period is proposed to shift substrate utilization toward fat oxidation and spare protein, consistent with reduced orexin-driven catabolic drive while asleep.

Counter-evidence held on record

This is a reverse-direction, apparently favorable finding in a single small trial, not a deficiency, and it does not support any supplement, weight-management, or energy-support product claim. Total energy expenditure was unchanged, so the fuel-shift finding should not be read as a meaningful net energy gain, and the n=14, single-night, healthy-men-only design should not be generalized.