MOTS-c is a 16-amino-acid peptide encoded in mitochondrial DNA, first described in mice in 2015 [2]. It is not FDA-approved, and current 503A records do not establish ordinary retail bulk-compounding eligibility [1]. Online sellers market it for weight, energy and insulin sensitivity. For what it is and where the mouse research stands, start with the MOTS-c overview.
Short answer: unknown, and FDA says so plainly
FDA’s July 2026 compounding assessment identified no clinical treatment studies or human exposure data within its review. The current recruiting protocol has no posted results. These sources do not establish reliable human side-effect rates.
| Question | What can be concluded | Evidence limit | Source |
|---|---|---|---|
| Appetite, fatigue or diarrhea | Reliable human treatment rates not established | Mouse feeding findings and anecdotal lists cannot quantify human risk | FDA review |
| Injection reactions | Potential immune/impurity concerns | No posted current trial results | FDA review; trial protocol |
| Long-term safety | Unestablished | Short protocols cannot exclude uncommon or long-term effects | FDA review |
What FDA’s assessment identified
Before its July 23, 2026 advisory committee meeting, FDA searched PubMed, Embase, the Cochrane database, ClinicalTrials.gov, its own adverse-event database and other references for anything on MOTS-c in people [1]. It found no pharmacokinetic study, no safety study and no exposure data.
The nomination did not include, and FDA has not identified, any clinical studies or human exposure data for MOTS-c via any route of administration. Therefore, potential safety risks associated with the use of MOTS-c-related BDSs in humans are unknown.[1]
FDA’s statement concerns the treatment evidence available in its assessment. Endogenous measurements and a current protocol are different kinds of human information; neither establishes an injected product’s safety or benefit.
No adverse-event reports, and why that isn't reassuring
FDA searched its adverse-event database twice, through February 28, 2024 and again through March 9, 2025, and found no MOTS-c reports [1]. In the same section FDA notes that 503A compounding pharmacies "generally do not report adverse events," and that it may not learn of problems unless someone files a report.
No reports in those dated searches cannot establish no harm or quantify reporting completeness. They also do not verify the identity of products outside the studies. A lack of submitted reports should not be converted into a reassuring adverse-event rate.
Does MOTS-c affect appetite? A dependable effect is unestablished
The reviewed evidence does not establish a reliable appetite effect from administered MOTS-c in people. The 2015 mouse study’s weight difference and food-intake measurements answer an animal-metabolism question, not what a person should expect to feel [2].
The paper itself says the weight difference wasn't explained by eating: calorie intake was identical between the groups [2]. In a separate 4-day test on a normal diet, treated mice showed modest drops in body weight, food intake and blood glucose. So the mouse data point to no change or slightly less eating, not more hunger. None of it tells you what a person will feel.
Whether MOTS-c changes body fat in people is a separate question, covered in does MOTS-c burn fat.
The quality risk FDA flagged: impurities and clumped peptide
FDA's review spends more space on manufacturing than on biology. It found little information on the impurities MOTS-c can carry, and noted that peptides like it can clump into aggregates, especially in storage [1]. Because of that, FDA said it "cannot rule out" immune reactions when MOTS-c is injected.
FDA’s current safety page places MOTS-c among withdrawn nominations. That change is not a finding of safety or an approval. Historical archive-date claims are omitted here unless the exact original document is established.
The "human trial" some sites cite tested a different drug
Some pages say MOTS-c has passed a human safety trial and point to ClinicalTrials.gov record NCT03998514. That record is a completed phase 1 study of a drug called CB4211 in 88 people, run from July 2018 to April 2021, with no results posted [4]. CB4211 is not MOTS-c, and the study can't speak to MOTS-c's safety.
A placebo-controlled trial of MOTS-c itself, in an estimated 120 adults with prediabetes and excess weight, was registered in 2026 and was recruiting as of this update [5]. That protocol has no posted treatment results; endogenous measurements in people answer different questions. How long the peptide lasts in the body is covered in how long MOTS-c stays in your system.
Who has the most reason to wait
- People on insulin or other glucose-lowering drugs: MOTS-c is studied for insulin sensitivity in mice, and no one has studied it alongside diabetes medicines. Ask your prescriber before trying any unapproved metabolic product.
- Anyone pregnant or breastfeeding: the reviewed sources do not establish safety in these populations, which the current protocol excludes.
- Competitive athletes: WADA's 2026 list names MOTS-c under S4.4.1, activators of AMP-activated protein kinase, prohibited at all times [3].
- Anyone with a history of allergic or immune reactions to injections, given FDA's concern about impurities.
Where MOTS-c stands, briefly
A reported advisory outcome is not drug approval or a new compounding exemption. Use current issued policy and regulations to establish eligibility; a pending review does not supply final terms [7].
The full status is on is MOTS-c FDA-approved, and what that means for buying it is on MOTS-c's legal status. For how sources are chosen on these pages, see how we check.
The current NCT07505745 record lists 120 estimated participants, recruiting at a site in China, with no posted results. Structured primary outcomes are insulin sensitivity at 12 weeks and adverse events through 16 weeks. Its detailed narrative also names body weight and waist circumference, although those are absent from the structured outcome list. That reporting difference prevents a categorical claim that weight will not be measured [6].