SS-31 (Elamipretide) on Juno

What it does

SS-31 (clinical name elamipretide) is a 4-amino-acid synthetic tetrapeptide that selectively partitions to the inner mitochondrial membrane and binds cardiolipin — a phospholipid critical for the electron-transport chain. It's the most clinically developed mitochondrial-targeted peptide. FDA-approved in 2024 for Barth syndrome (a rare mitochondrial disorder). Trials in mitochondrial myopathy, Leber's hereditary optic neuropathy, and age-related macular degeneration have produced mixed results — some endpoints met, others missed. Community use frames it as a general "mitochondrial rejuvenation" compound.

Used for

Dose

Starting: 40,000 mcg · once daily
Common: 50,000 mcg · once daily
Upper: 60,000 mcg · once daily
When: MorningMitochondrial-targeted. Daily dosing in the Barth syndrome trials was morning. No strong circadian signal in the data, but morning aligns with mitochondrial energy demand.
Site: subcutaneous

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⚠ Caution

Pregnancy and breastfeeding (limited human safety data outside trial populations)
Pediatric use outside formal trials
Active malignancy (mitochondrial bioenergetics intersects with cancer metabolism in complex ways)
Known hypersensitivity to elamipretide

Often stacked with

MOTS-c — MOTS-c activates AMPK and nuclear metabolic programs via mitochondria-to-nucleus retrograde signaling; SS-31 stabilises inner-membrane cardiolipin and improves electron-transport-chain efficiency — complementary mitochondrial targets.

Your stack

Track this peptide in your protocol — dose, schedule, vials on hand, refill projection. Stays in your browser; no account needed.

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Use this peptide

Featured in protocols

Energy & Vitality — Phase 2 — Mitochondrial layer

Co-injection & overlap

Inject separately (do not co-mix): MOTS-c

Reconstitution & storage

Trial / approved formulation is supplied as a sterile solution at fixed concentration (40 mg/mL in approved Barth product Forzinity). Compounded research-grade SS-31 powder is reconstituted with sterile saline; concentrations vary by vendor. Dose volumes are larger than typical peptide injections — multi-mL SubQ doses are common.

Storage. Approved product: refrigerate per label. Compounded sterile solutions: refrigerate 2–8 °C. Lyophilized: refrigerate; reconstituted within 30 days typical.

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Reference

How it works

Concentrates ~1000-fold in the inner mitochondrial membrane via electrostatic affinity, then binds cardiolipin and stabilizes the cristae structure. Restoring cardiolipin–cytochrome c interactions improves electron-transport-chain efficiency, reduces ROS leak, and preserves ATP production in stressed/aged mitochondria. Effect is downstream-corrective rather than upstream-stimulatory — it does not increase mitochondrial biogenesis directly, but improves the function of existing mitochondria.

Juno's take

SS-31 has a real approval pathway for Barth syndrome, which is a rare mitochondrial disorder with measurable cardiac and skeletal-muscle outcomes — the evidence there is solid. Other indications (mitochondrial myopathy, dry AMD, cardiomyopathy) produced inconsistent trial results — some signals, some negative readouts. The longevity-clinic use of SS-31 as a generic "mitochondrial rejuvenation peptide" goes well beyond what the trials measured, and the compounded vendor pricing tends to be aggressive. If you're considering this peptide for anything other than Barth syndrome under specialist care, the evidence base is much sharper than the marketing suggests.

EvidenceTier 2 — Human observational

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Barth syndrome (cardiolipin deficiency)

Tier 1high confidence

TAZPOWER and TAZPOWER-LTE trials provided sufficient evidence for FDA accelerated approval in 2024 (Forzinity) for adolescents and adults with Barth syndrome — a rare X-linked cardiolipin synthesis disorder. Tier 1 reflects approval for this orphan indication.

Reid Thompson W et al. 2021

Primary mitochondrial myopathy

Tier 2high confidence

MMPOWER-3 Phase 3 trial in primary mitochondrial myopathy missed its co-primary endpoints, but post-hoc and crossover-extension data showed signals of benefit on the 6-minute walk test. Tier 2 because the RCT is well-powered but the readout is mixed.

Karaa A et al. 2018

Age-related macular degeneration (geographic atrophy)

Tier 3high confidence

ReCLAIM-2 Phase 2b in dry AMD did not meet its primary endpoint. Some secondary signals exist. Tier 3 reflects underpowered Phase 2 evidence and an unconverted hypothesis.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

General 'mitochondrial rejuvenation' / longevity

Tier 4high confidence

Used in community/longevity-clinic settings as a general anti-aging mitochondrial intervention. There are no RCTs in healthy aging — the entire trial program was in defined mitochondrial diseases. Mechanism-as-evidence reasoning.