If you have already received something called MOTS-c, bring its name and any paperwork to your clinician. Start with what you received and what you have noticed.
Need urgent help now?
MedlinePlus lists difficulty with breathing or swallowing, and a swollen face or tongue, among the possible signs of a severe allergic reaction. A
For a severe allergic reaction, dial 911 or go straight to the nearest emergency room.
The missing human information
The agency that reviews US medicines is the FDA. In its review checked September 30, 2026, the harms of giving MOTS-c to people remained unknown. B
The FDA searched its stored reports of unwanted effects from medicines. It found no reports for MOTS-c. That does not show that MOTS-c is safe.
Ordinary pharmacies making medicines to order generally do not report these unwanted effects to the FDA.
Why the body's defences concern the FDA
FDA reviewers raised the possibility that injected MOTS-c could trigger the body's defences, in the review checked on September 30, 2026. B
Clumps or unwanted material in an injected peptide may prompt the body to treat it as an invader.
The FDA described a possible harm. It did not measure how often people have such reactions to MOTS-c.
Pregnancy and breastfeeding remain unanswered
As of September 30, 2026, there was no established pregnancy or breastfeeding information for MOTS-c. B
Rules about who may join a study are choices for that research. They are not official instructions about who can safely use MOTS-c. Being allowed into a study does not answer the pregnancy or breastfeeding question.
Tell the clinician if pregnancy or breastfeeding is part of your situation. Ask how the missing information affects the proposed choice.
If you compete under world sport rules
On the list checked September 30, 2026, the World Anti-Doping Agency bans MOTS-c during competitions and between them. C
Ask your sport's governing body which rules apply before making a care decision. The substance being made by the body does not answer that question.
Carry this with you
Ask what studies have found about harm in people. Finding no side-effect reports does not show that MOTS-c is safe.
Source notes for this page
The symptoms above are reasons to seek urgent help, rather than a diagnosis from this page.
The FDA review says the harms in people remain unknown. It describes possible reactions from the body's defences, but not how often they happen.
This sport ban applied on September 30, 2026. Ask your sport's governing body which rules apply to you.