PCAC Briefing · Thursday, July 23, 2026
MOTS-c before the compounding committee
FDA proposes not adding either MOTS-c substance to the 503A Bulks List. Of the seven, this evaluation records the emptiest file: no nonclinical data to inform safety for the potential clinical uses, and no clinical studies of safety or effectiveness in humans.
Published July 16, 2026 · By the Grey Peptides Editorial Board · ✓ Sourced from FDA's briefing document
| Substances | MOTS-c (free base) and MOTS-c acetate |
| Also known as | Mitochondrial ORF of the 12S rRNA type-c |
| Length | 16 amino acids |
| Use FDA reviewed | Obesity and osteoporosis |
| Forms proposed | Injectable, per the nomination package |
| Nomination | Nomination withdrawn; FDA evaluated at its own discretion |
| FDA staff position | Proposes not adding either form to the 503A Bulks List |
What FDA reviewed it for
Nominated for insulin resistance, obesity, osteoporosis, vascular calcification, muscle and fat metabolism, and longevity. FDA evaluated obesity and osteoporosis.
This is not a detail to skip past. FDA evaluates a bulk drug substance in the context of the use proposed for it — so the question in front of the committee is not "is MOTS-c useful?" but "does the evidence support compounding MOTS-c for obesity and osteoporosis?" A substance can have an interesting research literature in a completely different area and still fail this test, because that literature was never the thing under review.
FDA's specific objections
FDA weighs four criteria: whether the substance is well characterised physically and chemically, whether it has been used historically in compounding, what evidence exists on effectiveness, and what safety issues its use in compounding raises. Here is where MOTS-c landed on each.
FDA says MOTS-c (free base) is not well characterised, citing nomenclature inconsistency and the absence of quality control attributes — impurities, aggregates, endotoxins — in the published literature, plus no Certificate of Analysis in the nomination. It also flags missing water-solubility data, which prevented a conclusion on whether solubility would affect the proposed formulation.
FDA describes the extent of use in compounding as unknown.
No clinical studies assessing effectiveness in humans.
No available nonclinical data to inform safety considerations for potential clinical uses, and no clinical studies in humans. FDA notes it lacks the information needed to assess immunogenicity risk for a 16-amino-acid peptide.
What is specific to MOTS-c
Six of the seven objections above could be written about almost any of the compounds on the July agenda. These next points could not — they are what makes this file different from the other six.
MOTS-c appears as a prohibited substance in the Global Drug Reference Online database, which draws on the 2024 WADA Prohibited List — under hormone and metabolic modulators. As with TB-500, a compounding decision would not change anti-doping status.
FDA's own internet search found a holistic clinic stating it works with compounding pharmacies to obtain compounded MOTS-c products, and a wellness clinic promoting an IV therapy cocktail containing MOTS-c without disclosing the other ingredients.
MOTS-c is popularly discussed as a longevity and exercise-mimetic compound. FDA evaluated it for obesity and osteoporosis — the uses the nomination proposed that it had enough information to assess.
The evidence picture
Grey Peptides grades MOTS-c's evidence base as low. It is preclinical and early translational work — largely mouse studies and human observational associations. FDA's finding of no clinical studies in humans is consistent with that.
Two readings of the same file are worth separating. FDA's conclusion is about a regulatory question — whether the record supports letting pharmacists compound this substance for this use. That is a higher bar than "there is some interesting science here," and a lower bar than "this substance is harmful." Almost everything FDA said about MOTS-c is a statement about missing information, not a finding of harm. Reporting that as "FDA says MOTS-c is dangerous" is wrong. So is reporting it as "FDA found no safety problems."
Where this sits in our encyclopedia
Our entry on this compound covers the underlying pharmacology, the published literature, and the status picture independent of this meeting. The two are separate reads: the encyclopedia entry is about the compound, and this page is about the regulatory file.
Mechanism, evidence grade, half-life, approval status, and sources. PCAC July 2026 — the full picture
All seven compounds, what the vote does and doesn't change, and what to watch. Peptide Regulatory Status Tracker
Category 1/2/3, 503A vs 503B, and where every peptide sits.
The other six compounds
BPC-157 · KPV · TB-500 · Emideltide (DSIP) · Semax · Epitalon
FDA — July 23–24, 2026 Meeting of the Pharmacy Compounding Advisory Committee ↗
FDA briefing documents released June 29, 2026. Federal Register notice 91 FR 20465, published April 16, 2026 (FR Doc. 2026-07361), Docket No. FDA-2025-N-6895. FDA Briefing Document for MOTS-c (free base) and MOTS-c acetate, released June 29, 2026.