What Is SS-31 (Elamipretide)? Dosage & How to Track It

What SS-31 is and how it works

SS-31 — the clinical name is elamipretide — is a synthetic tetrapeptide, just four amino acids, small enough to cross the outer mitochondrial membrane and concentrate inside mitochondria themselves rather than acting from outside the cell like most peptides. Its target is cardiolipin, a lipid found almost exclusively in the inner mitochondrial membrane, where it’s essential for organizing the electron transport chain — the machinery that produces ATP, your cells’ energy currency.

By binding cardiolipin, SS-31 appears to stabilize electron transport chain complexes, which does two things at once: it reduces the leakage of reactive oxygen species (a byproduct of a struggling electron transport chain and a driver of oxidative damage), and it improves the efficiency of ATP synthesis. That combination — less oxidative stress, more usable energy — is why it’s been studied across a wide range of conditions where mitochondrial dysfunction plays a role: heart failure, neurodegenerative disease, and age-related muscle loss.

The notable fact that separates SS-31 from most peptides in this library: it isn’t purely investigational. In 2025 the FDA granted elamipretide accelerated approval under the brand name Forzinity, specifically for Barth syndrome — a rare genetic mitochondrial disorder causing cardiomyopathy and muscle weakness, mostly in boys. That approval covers that one specific condition; broader uses (heart failure, general mitochondrial support, anti-aging) remain investigational and are not what the drug is approved for.

Typical dosing & reconstitution

SS-31 ships lyophilized across several vial sizes and is reconstituted with bacteriostatic water. Research protocols run 5–10 mg once daily subcutaneously at a consistent time, sometimes titrated from a lower starting dose; some advanced protocols reach 15–20 mg/day, though that range warrants supervision.

Reconstitution varies by vial size:

At 10 mg/mL, a 5 mg dose is exactly 50 units — half a standard insulin syringe — which is why smaller vials are reconstituted concentrated on purpose: SS-31 doses run high relative to most peptides, and a dilute mix would push a single dose past what one syringe can hold.

Half-life & what it means for frequency

SS-31’s blood half-life is relatively short — on the order of a few hours — which is the basis for once-daily dosing at a consistent time rather than a less frequent schedule. Because it works by binding directly to cardiolipin in the mitochondrial membrane, some of its functional effect may outlast the compound’s presence in blood.

The practical takeaway is the same as most short-half-life peptides: consistency matters more than precise timing, and there’s no depot to smooth over a missed or late dose.

What to track & common side effects

In the clinical trials that led to its Barth syndrome approval, elamipretide was generally reported as well tolerated, with injection-site reactions the most common issue. Because it’s a mechanistically well-characterized compound with real trial data behind it, the side-effect profile is better documented than most peptides in this library — but outside the approved indication, it’s still used off-label or as a research peptide, and product quality from non-pharmaceutical sources varies.

What’s worth tracking: the daily dose and site, and whatever energy, recovery, or performance marker motivated starting it — mitochondrial-support compounds tend to produce gradual, cumulative changes rather than an obvious single-dose effect, so a multi-week trend line is what actually tells you something.

Frequently asked questions