Evidence signal01
The biological premise is scientifically substantive
FDA reviewed mitochondrial signaling and rodent metabolic findings. These are legitimate research inputs, not fabricated claims or mere marketing copy.
FDA briefing pp. 25–27Day 1 recordPCAC favorable
Peptide dossier / July 23–24, 2026MOTS-c
Strong discovery science met an absent administered-human evidence bridge.
The scientific premise is mitochondrial and metabolic, but FDA said it found no clinical study or human-administration evidence and no adequate nonclinical toxicity package.
Decision boundaryPCAC advice is not FDA approval, does not establish safety or effectiveness, and did not itself place either form on the 503A Bulks List.
Editorial review
Analysis
FDA staff recommended against both forms; PCAC voted favorably on both form-level questions.
Decisive limitation02
No administered-human bridge was identified
The record did not show whether injected MOTS-c reaches active concentrations in people, what dose is relevant or what the human safety profile looks like.
FDA briefing pp. 27–33PeptideBase read
The committee outcome belongs beside the evidence record—not on top of it. A favorable advisory vote describes the panel’s recommendation on compounding eligibility; it does not erase FDA’s characterization, route-match or human-evidence concerns.
The case made in the room
Testimony
These are attributed testimony arguments, not PeptideBase endorsements. Each one is paired with the most relevant FDA answer and an explicit assessment of what the evidence can—and cannot—carry.
2published speaker moments
Only named speaker moments reconciled against a word-timestamped machine transcript of the official recording appear here. The method is two-pass transcript reconciliation: both passes read that same transcript, so this is not audio review and not independent primary-source confirmation. Where the two passes disagreed about who was speaking, the moment was withheld rather than published. Statements remain attributed arguments unless the underlying evidence was independently established from a named source outside the hearing record, and each moment carries its own disclosed limitations.
01Regulated-access context · not substance-specific
Pinchas “Hassy” Cohen, MD
Dean, USC Leonard Davis School of Gerontology; investigator whose lab first described MOTS-c
Verify credentialsAttributed testimony
The discovery-science case
Cohen identified himself as dean of USC’s gerontology school and said MOTS-c was discovered in his laboratory. He described it as a mitochondria-encoded metabolic regulator and summarised preclinical work on metabolism, muscle biology and age-related decline, then argued for routing existing use into supervised 503A compounding.
What is not established
- Identity is the strongest in this corpus (self-introduction plus two independent cross-references by other speakers), but the moderator’s own naming is garbled and does not match.
- MOTS-c ships with no opposing public-comment voice: two strong opposing candidates were held back on an identity-evidence disagreement between the two reconciliation passes. See docs/fda/unpublished-testimony-candidates.md.
MOTS-c session · discovery evidence and a general regulated-access argumentTranscript-reconciled — second review passed; stance basis citedPlay the source10:08:33–10:13:10
02Opposes listing
Peter Lurie, MD, MPH
President and Executive Director, Center for Science in the Public Interest; former FDA Associate Commissioner
Verify credentialsAttributed testimony
The hearing-wide case against all seven
Lurie said CSPI opposed adding all seven substances, for three reasons: that listing would be inconsistent with FDA’s own compounding standards, that compounded products pose distinct consumer risks, and that listing would remove incentives to develop products through the standard drug-approval pathway.
What is not established
- Identity rests on a self-introduction plus the chair’s sequential numbering ("speaker number three"), not on the chair speaking his name.
BPC-157 session public comment, speaker #3 · explicitly applied to all seven substancesTranscript-reconciled — second review passedPlay the source00:57:02–00:59:43
Discovery science and endogenous mitochondrial biology support clinical interest in MOTS-c.
Discovery, animal and association evidenceWhat supports it
Cohen described the peptide’s discovery and preclinical metabolic and muscle findings. Endogenous levels and human associations are not evidence of what an administered compounded product does.
FDA’s answer
FDA identified no human-administration studies and found a lack of evidence to evaluate effectiveness for the nominated uses.
FDA Day 1 presentation · 10:59:54PeptideBase assessment
The discovery record is scientifically important. It does not establish effectiveness, dose or safety after exogenous administration to people.
Why the judgments diverged
Promising endogenous biology did not answer the administration question.
The favorable majority appears to have found the discovery science and biological rationale sufficient for a positive recommendation. FDA separated endogenous occurrence and preclinical promise from evidence about administering a compounded MOTS-c product to people.
Editorial inference from the hearing record—not an attributed rationale for every voterClaim versus record
Claim checks
These are recurring propositions in the wider peptide discussion, not attributed speaker quotations.
Recurring claim
Human genetic associations show injected MOTS-c works in people.
Official record
FDA reviewed mechanistic and association-based material but said it found no clinical studies evaluating administration of MOTS-c to humans.
What it does not establish
FDA briefing pp. 25–30Human association data and endogenous biology do not establish the pharmacology, dose response, safety or effectiveness of an injected exogenous product.
Recurring claim
Injected MOTS-c will remain intact long enough to reach active concentrations.
Official record
FDA cited an in-vitro study reporting rapid hydrolysis in human blood and said it remained unknown whether exogenous administration could generate pharmacologically active concentrations over time.
What it does not establish
FDA briefing pp. 25–27The in-vitro result raises an exposure question; it does not by itself prove clinical inactivity.
Evidence architecture
Evidence
“Absent” means FDA said it did not identify that evidence within this evaluation. It is not a universal claim that no evidence exists anywhere.
| Evidence question | Status | FDA-record summary | Locator |
|---|---|---|---|
| Human clinical evidence | absent | FDA-record summaryFDA said it identified no human-administration clinical studies. | LocatorBriefing pp. 27–30 |
| Nonclinical evidence | indirect | FDA-record summaryRodent metabolic pharmacology was reviewed, but FDA said its clinical relevance was unknown. | LocatorBriefing pp. 25–30 |
| Exact-form match | limited | FDA-record summaryThe record did not establish a complete clinical evidence package for free base or acetate. | LocatorBriefing pp. 6–18 |
| Nominated-route match | absent | FDA-record summaryThe nomination proposed SC injection; FDA identified no human administration evidence. | LocatorBriefing pp. 6, 27–30 |
| Evaluated-use match | absent | FDA-record summaryFDA did not evaluate any of the six nominated uses — insulin resistance, obesity, osteoporosis, vascular calcification, muscle/fat metabolism and longevity — because the nomination did not include sufficient information for the Agency to evaluate whether the substance is appropriate for them, and FDA identified no clinical studies evaluating those uses. | LocatorBriefing p. 7, footnote 4 |
| Product characterization | not well characterized | FDA-record summaryFDA concluded that “MOTS-c (free base) is considered to be not well-characterized from the physical and chemical characterization perspective”; the same conclusion is stated for MOTS-c acetate. | LocatorBriefing pp. 7–18 |
| Human safety | absent | FDA-record summaryNo clinical exposure data were identified, and FDA found no adequate acute, repeat-dose, genotoxicity, reproductive or carcinogenicity studies. | LocatorBriefing pp. 25–29 |
| Historical compounding use | limited | FDA-record summaryFDA found the extent of historical use in compounding unknown. | LocatorBriefing pp. 18–23 |
Qualitative evidence map · no numerical score · scoped to FDA’s July 2026 evaluation
FDA findings
Five parts of the staff case.
01characterizationBoth MOTS-c free base and MOTS-c acetate were considered not well characterized.Day 1 pp. 131, 134
10:54:0202effectivenessFDA found a lack of evidence to evaluate effectiveness for the nominated uses and identified no human-administration studies.Day 1 p. 138
10:59:5403safetyFDA found a lack of clinical and nonclinical safety information.Day 1 pp. 139–143
11:02:4704historical useFDA found the extent of historical use in compounding unknown.Day 1 pp. 144–147
11:04:3905recommendationFDA proposed that neither MOTS-c free base nor MOTS-c acetate be included on the 503A Bulks List.Day 1 pp. 147–148
11:06:02
10:54:0202effectivenessFDA found a lack of evidence to evaluate effectiveness for the nominated uses and identified no human-administration studies.Day 1 p. 138
10:59:5403safetyFDA found a lack of clinical and nonclinical safety information.Day 1 pp. 139–143
11:02:4704historical useFDA found the extent of historical use in compounding unknown.Day 1 pp. 144–147
11:04:3905recommendationFDA proposed that neither MOTS-c free base nor MOTS-c acetate be included on the 503A Bulks List.Day 1 pp. 147–148
11:06:02
What changes the assessment
Sources
A useful dossier should show the reader what evidence could materially strengthen or weaken the current read.
01
Human-administration trials with pharmacokinetics and dose response
02
Acute, repeat-dose, genetic, reproductive and carcinogenicity testing
03
Resolved hearing scope plus exact form and finished-product specifications
Decision boundaryPCAC advice is not FDA approval, does not establish safety or effectiveness, and did not itself place either form on the 503A Bulks List.
Continue the record
View all sevenRelated peptide dossiers
Day 2
Epitalon
The official record contained circadian and melatonin-related findings, but no direct insomnia trial using the nominated SC product and no clinical safety record.
Open dossierDay 1TB-500
The central technical issue is identity: FDA treated the seven-amino-acid TB-500 fragment as distinct from full-length thymosin beta-4 and found no direct human TB-500 evidence.
Open dossier