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PEPTIDESUNCENSORED

SS-31

/S · S thirty-one (el-ah-MIP-reh-tide)/aka Elamipretide, Forzinity, MTP-131

Mitochondria-targeted tetrapeptide that binds cardiolipin in the inner membrane. FDA-approved as Forzinity for Barth syndrome.

SubcutaneousDaily
Open in cycle visualizer

SS-31: educational research discussion. Not medical advice. Not a protocol for you.Details

Reported range
40 mg daily
Frequency
Once daily
Cycle length
Continuous (label)
Half-life
Short; peaks at 0.5–1 h
Route
SC

Reported figures describe what is published or discussed. None of them is a dose for you.

Mechanism

What it is proposed to do

Elamipretide is a small, cell-permeable peptide (D-Arg-Dmt-Lys-Phe-NH2) with alternating aromatic and positively charged residues. It concentrates in the inner mitochondrial membrane and binds cardiolipin, the lipid that holds the electron transport chain's supercomplexes together. In cell and animal studies this stabilizes cristae, improves electron transport and lowers oxidant production. Barth syndrome is caused by defective cardiolipin, which is exactly where that mechanism should matter most.

  1. 01

    SS-31

    4 residues, alternating aromatic and cationic

    established
  2. 02

    Cardiolipin binding

    Inner mitochondrial membrane, shown in lab studies

    established
  3. 03

    Cristae · electron transport

    More efficient respiration, less oxidant leak in cells and animals

    proposed
  4. 04

    Muscle strength in Barth syndrome

    The surrogate behind the accelerated approval

    established
EstablishedProposed from animal or cell data

Half-life. Short. Label data show rapid absorption, with peak levels 0.5–1 hour after injection, and breakdown to inactive fragments cleared by the kidneys.

Dosing & cycles

What is reported, and where it comes from

Numbers below are labeled FDA label, clinical trial range or commonly reported range. They describe the published and discussed landscape. They are not instructions and not a protocol for you.

Dosing studio

Every figure is labeled by where it comes from.

This is not your dose

Scale view: Forzinity label dose (Barth syndrome)

10
20
30
40
50
60
70

Probe at 40 mg: at the listed figure Drag it to read the scale. It does not pick a number for you.

Typical cycle, as a calendar

Label pattern: daily, continuous

Continuous

One injection a day, continuously, for the approved indication. The label does not describe cycling.

OffLow / startMid / loadingHigh / maintenance

Cycle patterns

Label pattern: daily, continuous

Continuous

One injection a day, continuously, for the approved indication. The label does not describe cycling.

Daily
Week 1Week 24

Stacks

What it gets combined with

Why people pair things, and what nobody has tested.

Mitochondria stack

3 compounds
SS-31MOTS-cNAD+
Why people combine these
Pitched as covering the mitochondrion from three angles: the membrane (SS-31), signaling (MOTS-c) and fuel (NAD+).
Caution
Three mechanisms, no combination data, and only one of the three has an approved indication, for a rare disease.
What is unknown
No published human data on this combination: dosing, interactions and long-term effects are all unstudied.

Evidence

How much of this is known

Evidence grade

B

Human RCTs, narrow

Human RCTs exist but are narrow, early, or not for the popular use.

How we grade

An FDA approval, but an accelerated one for a single rare disease, based on a muscle-strength surrogate from small studies. Phase 3 and Phase 2 trials in commoner conditions missed their main goals. Graded B, not A, because the approved evidence base is small and the popular longevity use has no trials.

Human trial status

The Barth syndrome approval rests on improved knee-extensor strength, a surrogate expected to predict benefit, from a small program. In the TAZPOWER trial the 12-week randomized phase did not meet its primary or secondary endpoints; improvements appeared later in the open-label extension. In primary mitochondrial myopathy, the Phase 3 MMPOWER-3 trial missed its primary endpoints (2019). As intravenous Bendavia, it did not reduce infarct size in 118 heart-attack patients (EMBRACE STEMI). No trial tests it for ageing or general performance.

Limitations

  • Accelerated approval: benefit still has to be confirmed in a randomized trial.
  • The approved population is small and genetically specific.
  • Negative or null results in larger, commoner conditions.
  • Longevity claims extrapolate from cell and animal studies.

Sources to read

Links open PubMed, DailyMed, FDA or trial-registry searches. We do not cite what we have not described accurately.

Safety

Side effects, cautions, status

Commonly reported effects

  • Injection-site reactions dominate the label: redness in 100% of treated patients vs 25% on placebo, pain 75% vs 42%, hardening 67% vs 17%, itching 67% vs 17% (small patient numbers).
  • Hypersensitivity reactions, including rash and breathing symptoms, have been reported.
  • The approved product contains benzyl alcohol and is not for use in newborns.
  • Research-market "SS-31" identity, purity and sterility are unverified.
Injection-site reactionsUnknown long-term profile

Who should be extra cautious

  • Known hypersensitivity to elamipretide. The label's only contraindication.
  • Severe kidney impairment. Cleared by the kidneys; the label halves the dose.
  • Pregnancy or breastfeeding. Human data are very limited.
  • Gray-market product. Not the approved drug. Identity and quality are unverified.
  • Tested athletes. Not named by WADA; confirm status with your federation.

Legal & regulatory status

FDA granted accelerated approval on September 19, 2025, as Forzinity (elamipretide), to improve muscle strength in Barth syndrome patients weighing at least 30 kg. Continued approval depends on a confirmatory randomized trial. Any other use is off-label, and research-market "SS-31" is not the approved product.

WADA. Not named on the Prohibited List. Now that it holds FDA approval, the S0 catch-all for unapproved drugs no longer clearly applies. Confirm with your federation before using any metabolic or mitochondrial agent.

Storage & handling, high level

The approved product is handled per its label. Research-market vials are lyophilized powder of unverified identity, and nothing here makes the two equivalent.

Reconstitution and injection technique are clinical skills. The reconstitution calculator does arithmetic only.

FAQ

Questions people ask about SS-31

Is SS-31 FDA-approved?
Yes, narrowly. Elamipretide (brand name Forzinity) received accelerated approval in September 2025 for Barth syndrome in patients weighing at least 30 kg. It is not approved for anything else, and continued approval depends on a confirmatory trial.
Does it slow ageing?
Unknown in humans. The mitochondrial mechanism is real and well studied in cells and animals, but no trial has tested it for ageing, energy or performance.
Why did the bigger trials fail if the mechanism is sound?
A sound mechanism does not guarantee a measurable benefit. In primary mitochondrial myopathy and in heart attack patients, trials did not show the improvements they were designed to detect. Barth syndrome, where cardiolipin itself is defective, is where the mechanism has the most direct target.
Is research-market SS-31 the same as Forzinity?
No. Forzinity is made and released under FDA oversight. A research-market vial carries the same name but no verified identity, purity or sterility.

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