SS-31 UK: What Is It, and Should It Really Come Before MOTS-c?

A new name has started popping up in UK peptide chats: SS-31.

A few days ago it was a single question: has anyone tried SS-31? Now the same group is asking what it is, what it is meant to do, and whether it should be taken before MOTS-c to stop the “crash” some people say they get.

SS-31 is more interesting than most of the names that go round peptide groups. It has a proper medical name, elamipretide, and it has been through years of real clinical trials. In the US, it has even been approved as a medicine for one very rare disease.

But that is a long way from what is being said about it online. So we have looked at each claim in turn.

Community Questions editorial note: This article reports themes and questions emerging from real online peptide communities. These are personal experiences and discussions, not medical evidence or medical advice. The Peptide Brief does not verify individual claims. Always speak to an appropriately qualified healthcare professional before making changes to your treatment.

How Common Is This Discussion?

SS-31 is still a niche name, but it has gone from nothing to a proper conversation very quickly.

In one UK peptide community we follow, the first clear question appeared around 23 September 2026. It came up again the next day. By 26 September it had turned into a wider discussion, with several people asking questions and passing on things they had heard.

It is a pattern we have seen before. A single mention turns into repeated questions, then claims about what it does, then links to a peptide people already know (in this case MOTS-c). Around the same time, SS-31 also became available from a seller connected to the group, which probably explains some of the sudden interest.

What People Are Saying

The questions are mostly simple ones. What actually is SS-31? What is it supposed to do? Is it something to do with mitochondria, the tiny “batteries” inside our cells?

The biggest talking point is MOTS-c. One person said they had seen messages saying SS-31 should be taken before MOTS-c. Another said they kept getting a “crash” on MOTS-c and were thinking about trying SS-31 first, then going back to MOTS-c.

The idea going round is that SS-31 somehow “preps”, “repairs” or “restores” your mitochondria so MOTS-c works better and the crash does not happen.

Age has come up too, especially the idea that this matters more once you are in your 40s or 50s. People have also talked about energy, sleep and recovery.

These are the questions and claims we set out to check. They are not evidence that SS-31 does any of these things.

What Is SS-31?

SS-31 is the old research name for elamipretide. It is a small, man-made peptide developed by a US company called Stealth BioTherapeutics.

It is designed to travel into the mitochondria. These are the parts of our cells that turn food and oxygen into usable energy.

Once there, it sticks to a fat called cardiolipin, which sits in the inner wall of the mitochondria. Cardiolipin helps hold the energy-making machinery together. The US prescribing information describes elamipretide as a cardiolipin binder that improves the shape and function of mitochondria.

Unlike many peptides discussed online, elamipretide has been tested in people, in proper trials, for years.

Is SS-31 an Approved Medicine?

In the US, yes, but only for one rare disease.

In September 2025, the US Food and Drug Administration (FDA) approved elamipretide under the brand name Forzinity. It is approved to improve muscle strength in adults and children with Barth syndrome who weigh at least 30 kg.

Barth syndrome is a very rare inherited condition, mostly affecting boys and men. It is caused by a faulty gene that means the body cannot make cardiolipin properly. That is exactly the fat elamipretide sticks to, which is why this condition was a good fit.

A few important details:

• It was an accelerated approval. That means the FDA approved it early, based on an improvement in leg (knee) muscle strength, while the company carries out further trials to confirm it really helps patients.
• The main trial behind it involved just 12 people. In the placebo-controlled part of that trial, elamipretide did not improve walking distance or fatigue scores. The strength gains were seen later, in an open-label extension where everyone knew they were getting the drug.
• The most common side effect was reactions where the injection goes in, such as redness, pain or itching.

So the approval is real, but it is narrow. It says nothing about using SS-31 for energy, ageing or alongside other peptides in healthy people.

Where Does SS-31 Stand in the UK?

We could not find any UK licence for elamipretide. The MHRA’s public database of licensed medicines has no results for it. That does not mean the MHRA has rejected elamipretide or decided that it does not work. It means we could not identify a UK marketing authorisation for it.

There has been some early UK paperwork. In December 2024, a UK pharmaceutical company announced it had submitted a paediatric investigation plan for elamipretide to the MHRA, which it described as its first regulatory step towards bringing the medicine to market. MHRA records indicate that a plan for Barth syndrome was agreed in January 2026.

A paediatric investigation plan is simply an agreed plan for how a medicine will be studied in children. It is not an approval, and it does not mean the medicine can be prescribed in the UK.

US approval does not carry over to Britain either. And any future UK licence would cover the specific medical use it was assessed for, such as Barth syndrome, not energy or anti-ageing.

Does SS-31 “Repair” Mitochondria?

“Repair” is a big word, and it is not really the right one.

What the research shows is that elamipretide binds to cardiolipin and, in lab and animal studies, helps the inner wall of the mitochondria keep its shape and work more efficiently. In one small human study, which we look at below, it gave a short-term boost to how much energy older people’s muscle cells could produce.

That is interesting. But it is not the same as “repairing” damaged mitochondria, fixing them for good, or resetting them so another peptide works better. We could not find human evidence that SS-31 does any of those things.

Should SS-31 Be Taken Before MOTS-c?

This is the big question in the group, and the honest answer is that there is no evidence for it.

We looked for human trials, animal studies or lab research testing SS-31 and MOTS-c together, or one before the other. We could not find any. The “SS-31 first, then MOTS-c” idea appears to come from online protocols and seller or influencer content, not from published research.

It is easy to see how the idea started. Both are linked to mitochondria. MOTS-c is a peptide the mitochondria make naturally, and SS-31 targets the mitochondria. So it sounds logical that one might “prepare” the ground for the other.

But sounding logical is not the same as being tested. Two compounds being linked to the same part of the cell does not tell us they work together, that the order matters, or that combining them is safe.

MOTS-c itself is still largely experimental, and it is not a licensed medicine in the UK. You can read more in our article What Is MOTS-c? Why People Are Talking About This Peptide.

Can SS-31 Stop the MOTS-c “Crash”?

We could not find any evidence that it can.

We also could not find any research that describes or explains a “MOTS-c crash”. That does not mean people are not feeling something. But at the moment, the crash is something people report in chats, not something that has been studied.

So the idea that SS-31 prevents it is a guess built on another guess. If someone keeps feeling unwell after taking something, the safer step is to stop and talk to a doctor or pharmacist, not to add another unlicensed peptide.

Does SS-31 Give You More Energy?

This is where the trials are most useful, and the results are more mixed than the online chat suggests.

One of the biggest trials, MMPOWER-3, tested elamipretide in adults with primary mitochondrial myopathy. This is a genetic muscle condition where the mitochondria do not work properly, so tiredness and muscle weakness are central symptoms. It was a placebo-controlled trial, published in 2023.

Elamipretide did not improve the two main things being measured: how far people could walk in six minutes, and how tired they felt. It was generally well tolerated.

In Barth syndrome, as mentioned above, the placebo-controlled part of the trial also did not show better walking distance or fatigue scores.

These are people with serious mitochondrial disease, the group most likely to benefit. If the drug did not clearly improve fatigue for them in these trials, there is no good reason to assume it will boost energy in otherwise healthy people.

Is SS-31 More Useful as You Get Older?

This is the claim with the most research behind it, but it is still early.

Our mitochondria do tend to work less well as we age, and elamipretide has been studied in older animals, with some encouraging results in mice.

In people, the key study is a small trial published in 2021. It gave 39 healthy adults aged 60 to 85, chosen because their muscle mitochondria were not working well, a single two-hour drip of elamipretide or a placebo. Straight afterwards, the energy-making capacity of a small hand muscle went up more with elamipretide than with placebo.

But the muscle did not get better at resisting tiredness, which was the practical measure. It was also a single dose given through a drip, not repeated injections over weeks, and it did not look at energy levels in daily life, ageing or long-term health.

So there is a real scientific reason researchers are interested in ageing. But we could not find evidence that SS-31 makes healthy people in their 40s, 50s or older feel more energetic or age better.

What About Sleep and Recovery?

We could not find any controlled human studies showing that SS-31 improves sleep or recovery.

These claims appear to come from personal reports and online marketing rather than research.

What About SS-31 Being Sold Online?

Being on sale does not mean something works, or that it is safe.

In the US, the FDA-approved elamipretide product is the prescription medicine Forzinity, manufactured to pharmaceutical standards. A vial sold online as “SS-31” or “research peptide” should not automatically be assumed to be equivalent to the pharmaceutical product used in clinical trials, whether in what it contains, its strength or its purity.

And as we have seen with other peptides, online sales and community buzz can move much faster than the science.

What We Still Do Not Know

There is still a lot that has not been answered:

• Whether elamipretide has any meaningful benefit in healthy people.
• Whether it helps with energy, sleep, recovery or ageing in everyday life.
• Whether taking it with, or before, MOTS-c changes anything, or is safe.
• What the long-term effects are outside the medical conditions it has been studied in.
• Whether products sold online match the medicine used in trials.
• Whether the US approval will be confirmed by further trials, and whether it will ever be licensed in the UK.

What This Means For People In The UK

SS-31 is a good example of why it pays to check before you believe what is said in a group chat.

Four things are worth remembering:

SS-31 is a real medicine candidate, elamipretide, with years of genuine clinical research behind it.

It is approved in the US for one rare disease, Barth syndrome, and is not licensed in the UK.

In trials, it did not clearly reduce fatigue, even in people with mitochondrial disease.

There is no evidence that it should be taken before MOTS-c, or that it stops a MOTS-c “crash”.

If you are tired all the time, or keep feeling rough on something you are taking, that is worth a proper conversation with your GP or pharmacist.

Key Takeaways

• SS-31 is another name for elamipretide, a peptide designed to target mitochondria by binding to a fat called cardiolipin.
• It was approved in the US in September 2025, as Forzinity, to improve muscle strength in people with Barth syndrome weighing at least 30 kg. This was an accelerated approval based on a trial of 12 people.
• We could not find a UK licence for elamipretide. Early MHRA paperwork on a children’s study plan is not an approval.
• In the large MMPOWER-3 trial, elamipretide did not improve walking distance or fatigue in people with mitochondrial muscle disease.
• A single dose raised muscle energy capacity in a small study of older adults, but did not make the muscle more resistant to tiredness.
• We found no research on taking SS-31 before or with MOTS-c, and no evidence that it prevents a MOTS-c “crash”.
• We found no controlled human evidence that SS-31 improves sleep or recovery.
• Products sold online as SS-31 should not be assumed to be the same as the approved medicine.

Further Reading

What Is MOTS-c? Why People Are Talking About This Peptide

Peptides — What They Are and Why the UK Is Talking About Them

Cartalax UK: What Is the ‘Cartilage Peptide’ People Are Talking About?

Sources

US Food and Drug Administration — Drug Trials Snapshots: Forzinity

DailyMed (US National Library of Medicine) — Forzinity (elamipretide) prescribing information

Karaa et al. (2023), Neurology — Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial

Roshanravan et al. (2021), PLOS ONE — In vivo mitochondrial ATP production is improved in older adult skeletal muscle after a single dose of elamipretide in a randomized trial

Pharmanovia (20 December 2024) — Submission of a paediatric investigation plan for elamipretide to the MHRA

MHRA Products — database of UK-licensed medicines (searched 26 September 2026)

This article reports themes and questions emerging from real online patient communities and does not constitute medical advice. Individual experiences vary. Always speak to an appropriately qualified healthcare professional before making changes to your treatment or considering any new compound.