SS-31 is a peptide four amino acids long. It gathers inside mitochondria, the parts of a cell that make energy, and sticks to a fat there.
What matters first
Why people look it up
It is sold online for energy, mitochondrial health and slower aging.
What the evidence shows
The same molecule is an approved medicine for a rare inherited condition, at 40 mg a day under the skin. It was tested for the reason people buy it. In 41 older adults with failing mitochondria, it moved energy production about as much as placebo. The vials sold for that use hold 5 mg, an eighth of one day.
Dose status
SS-31 is not FDA-approved, so no dosing label exists for it. The sections below explain what researchers tested and what remains unknown.
SS-31 at a glance: FDA-approved label, dosing basis, regulatory status, safety coverage, and cited-source count. These details summarize the available sources; they are not treatment recommendations.
Evidence snapshot
FDA-approved label
The fastest way to see what kind of evidence this page is built on.
Regulation
FDA approvedForzinity
Dose source
Human study2 reported dose rows
Safety evidence
5 listed safety findingsCommon and serious effects shown apart
SS-31 at a glance: FDA-approved label, dosing basis, regulatory status, safety coverage, and cited-source count. These details summarize the available sources; they are not treatment recommendations.
Medically reviewed by Jennifer Montecillo, MD · non-practicing medical reviewer·Reviewed 2026-08-13·open the primary sources
What is known about SS-31
SS-31 is a four-amino-acid peptide that gathers in the inner membrane of mitochondria and binds a lipid there called cardiolipin. Under the name elamipretide it became an FDA-approved medicine in September 2025, sold as Forzinity to improve muscle strength in Barth syndrome, a rare inherited condition. Every subcutaneous quantity ever published for it is the same one: 40 mg once a day. The vials sold online as SS-31 hold 5 mg.
SS-31 research and regulatory details: evidence quality, approval status, doses, handling, and presentation.
Topic
Value
Strongest source
FDA label
FDA approval
Approved (Forzinity)
Studied dosing
40 mg once a day, for people with Barth syndrome weighing at least 30 kg; the same 40 mg was used in every registered subcutaneous study of this molecule, from the 12-person crossover behind the approval to the 218-person phase 3 that was stopped— from the FDA-approved label
Studied dosing
20 mg once a day, where kidney filtration is under 30 mL per minute and the person is not on dialysis; it is the only reduction the label describes— from the FDA-approved label
Typical vials
5 mg
Every row links back to a source listed below. These facts are for reference, not a personal recommendation.
What the evidence for SS-31 is
The dosing numbers come from an FDA-approved prescribing label. FDA reviewed the manufacturer’s studies before approving the product, and the label can change when new dosing or safety information appears.
FDA label
What it establishes
The schedule was tested for the approved use, FDA reviewed the results, and the approved product must meet manufacturing standards.
What it does not establish
It does not show that every dose step is right for every person. A clinician still has to consider health history, side effects and other medicines.
Use these numbers for the named product and approved use. A different brand, product form or use may have a different schedule.
Where SS-31 is in clinical trials
26 registered studies; the program has reached phase 4, and 2 are still enrolling.
The soonest a running study expects to finish measuring people is August 2027. That is when the sponsor expects to finish collecting the main measurement. It is not a results date, and not a date anything goes on sale.
Phase 4Recruiting
Clinical Trial in Patients With Barth Syndrome- 4TAZPower
Stealth BioTherapeutics Inc. · Barth Syndrome · 48 participants planned · started July 2026
Main measurement due September 2029 (sponsor estimate)
ReNEW:Phase 3 Study of Efficacy, Safety & Pharmacokinetics of Subcutaneous Injections of Elamipretide in Subjects With Dry Age-Related Macular Degeneration (Dry AMD)
Stealth BioTherapeutics Inc. · Age Related Macular Degeneration (ARMD) · 313 participants · started May 2024
Main measurement due August 2027 (sponsor estimate)
Searched under the name elamipretide, which is how the registry files it.
A registered study means a sponsor filed a plan and started enrolling. It is not evidence the drug works, and most drugs tested in people never reach a pharmacy. Sponsors write and update these sources themselves; the National Library of Medicine publishes them without checking them.
FDA grants those on a marker rather than on how people function, and the marker here was knee extensor strength. Whether the approval stands depends on a confirmatory trial that has not reported. The approval covers Barth syndrome in people weighing at least 30 kg, and nothing else.
Material sold online as SS-31 is not that product. Forzinity is a ready-to-use solution at 80 mg per mL. The research vials hold a powder to be mixed, and no regulator has examined what is in them.
Every subcutaneous quantity ever published for this molecule is 40 mg once a day. A 5 mg research vial holds an eighth of one day at that dose
No published source states a dose for the way it is sold. That use is a powder mixed at home, for mitochondrial health, energy or longevity
What is sold as SS-31 is not the approved medicine. Forzinity is a ready-to-use solution at 80 mg per mL that is never mixed with water
The approval is an accelerated one. It was granted on knee extensor strength rather than on how people function, and a confirmatory trial has yet to report
The trial behind the approval enrolled 12 people and gave each of them both the drug and placebo in turn
A phase 3 trial in primary mitochondrial myopathy enrolled 218 people and was stopped. Its registry entry records the reason as the blinded part failing to meet its primary endpoints
Tested for the reason people buy it, it did not separate from placebo. In 41 older adults with mitochondrial dysfunction, the maximal rate of ATP production changed by 0.17 on the drug and 0.12 on placebo. The spread on each was far wider than the gap between them
A pilot in healthy older adults is recruiting, and it is open-label with one arm and no control group. Its stated aim is safety and how well people handle it, not benefit
The label warns against giving it to newborns, because the solution carries benzyl alcohol
Its approved use is Barth syndrome in people weighing at least 30 kg — an inherited condition affecting a few hundred people worldwide
Questions about SS-31
Is SS-31 FDA-approved?
Yes — it is sold as Forzinity. That is why the schedule on this site is quoted from a label rather than summarized from a study.
How is SS-31 taken?
By injection under the skin, once a day.
How does SS-31 differ from the other compounds in this class?
SS-31 is an approved medicine, but it is not a GLP-1 or amylin drug. It works through a different system, so its dose and results cannot be compared directly with weight-loss injections.
What is not known about SS-31?
It does not show that every dose step is right for every person. A clinician still has to consider health history, side effects and other medicines.
3primary sources, each with the day we read it — open the documents used on this page
