SS-31

SS-31, also known as elamipretide, is a small synthetic tetrapeptide that targets the inner mitochondrial membrane. It binds to cardiolipin, a lipid critical for mitochondrial structure, to stabilize cristae and improve energy (ATP) production Cardiolipin remodelling in mitochondrial therapeutics: translational evidence chains from elamipretide to emerging strategies+1. This mechanism helps cells maintain efficient energy metabolism and reduces oxidative stress.

SS-31 gained accelerated FDA approval in 2025 for Barth syndrome, a rare mitochondrial disorder, where it improved muscle strength in clinical trials Elamipretide: The first cardiolipin-directed mitochondrial therapeutic for Barth syndrome approved under accelerated approval+1. Research is ongoing for other conditions involving mitochondrial dysfunction, such as primary mitochondrial myopathy and age-related decline In vivo mitochondrial ATP production is improved in older adult skeletal muscle after a single dose of elamipretide in a randomized trial.

SS-31's primary action is cardiolipin-directed membrane stabilization. It concentrates at the inner mitochondrial membrane, binding to cardiolipin-rich domains to preserve lipid packing and cristae curvature Cardiolipin remodelling in mitochondrial therapeutics: translational evidence chains from elamipretide to emerging strategies+1. This supports the organization of respiratory chain complexes, leading to better ATP synthesis and reduced proton leak.

Recent research also shows SS-31 improves ADP uptake through the adenine nucleotide translocator, increasing ATP production efficiency The mitochondrially targeted peptide elamipretide (SS-31) improves ADP sensitivity in aged mitochondria by increasing uptake through the adenine nucleotide translocator (ANT). In older adults, a single dose boosted skeletal muscle ATP production, confirming target engagement in humans In vivo mitochondrial ATP production is improved in older adult skeletal muscle after a single dose of elamipretide in a randomized trial.

The strongest clinical evidence comes from Barth syndrome, where elamipretide significantly improved knee extensor muscle strength compared to placebo, leading to its FDA approval Elamipretide: The first cardiolipin-directed mitochondrial therapeutic for Barth syndrome approved under accelerated approval+1. In older adults, a single dose enhanced in vivo mitochondrial ATP production, suggesting rapid bioenergetic benefits In vivo mitochondrial ATP production is improved in older adult skeletal muscle after a single dose of elamipretide in a randomized trial.

In heart failure with preserved ejection fraction (HFpEF), improved myocardial energetics did not consistently translate into better heart function, highlighting a research gap Mitochondrial Targeting by Elamipretide Improves Myocardial Bioenergetics Without Translating into Functional Benefits in HFpEF. Preclinical studies show neuroprotective, anti-fibrotic, and anti-inflammatory effects in animal models of brain injury, lung fibrosis, and sepsis Elamipretide (SS-31) Improves Functional Connectivity in Hippocampus and Other Related Regions Following Prolonged Neuroinflammation Induced by Lipopolysaccharide in Aged Rats+2.

Research protocols predominantly use subcutaneous administration, with doses varying from 2 mg to 20 mg daily based on the goal and tolerance [community protocol]. Typical research timelines start with a 1-2 week titration phase (2-5 mg/day), followed by a 4-8 week standard phase (5-10 mg/day) to assess mitochondrial function [community protocol]. Higher-intensity protocols (10-20 mg/day) are used in short blocks for more severe dysfunction [community protocol].

The approved Barth syndrome regimen uses 40 mg daily, demonstrating the feasibility of chronic daily dosing Elamipretide: First Approval. Timing is flexible; morning dosing is common for energy support, and pre-exercise administration is sometimes used for acute performance Targeting Mitochondrial Dysfunction With Elamipretide (SS-31) Improves Skeletal Muscle Performance in a HFpEF Rat Model.

SS-31 is supplied as a lyophilized powder for injection, requiring reconstitution with bacteriostatic water for multi-dose use [community protocol]. After adding diluent, swirl gently until clear; avoid shaking. Store lyophilized powder at -20°C for long-term preservation and reconstituted solution at 2-8°C, using within 14-28 days [community protocol]. Sterile technique is essential to minimize contamination risk, as the primary tolerability issue is injection-site reactions rather than systemic toxicity Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives.

SS-31 has no well-defined drug interaction profile, but its mitochondrial effects warrant caution with other mitochondria-active compounds. Combining with antioxidants like NAC or CoQ10 is generally considered complementary, though stacking multiple agents may complicate effect attribution Targeting Mitochondrial Dysfunction With Elamipretide (SS-31) Improves Skeletal Muscle Performance in a HFpEF Rat Model+1. Use with mitochondriotoxic drugs (e.g., certain antibiotics, statins) should be monitored for potential masking of toxicity symptoms Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives. Additive effects may occur with anti-inflammatory therapies, as SS-31 can reduce NLRP3 inflammasome activity Elamipretide(SS-31) Attenuates Idiopathic Pulmonary Fibrosis by Inhibiting the Nrf2-Dependent NLRP3 Inflammasome in Macrophages.

SS-31 does not appear to require cycling due to receptor concerns, as it acts on membrane architecture rather than traditional receptors. However, community protocols often include breaks of 2-4 weeks after 6-8 week cycles to assess tolerance and manage injection-site reactions [community protocol]. The approved Barth regimen uses continuous daily dosing, suggesting no intrinsic need for cycling when clinically indicated Elamipretide: First Approval. Benefits may fade over days to weeks after stopping, without withdrawal symptoms Cardiolipin remodelling in mitochondrial therapeutics: translational evidence chains from elamipretide to emerging strategies.

Practitioners frequently combine SS-31 with other peptides for synergistic mitochondrial or repair benefits. Common stacks include MOTS-c for metabolic synergy, BPC-157 and TB-500 for tissue healing, and growth hormone secretagogues for performance Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives+1. Evidence for these combinations is largely anecdotal, with theoretical support from paired mechanisms. To attribute effects, introduce SS-31 first before adding another peptide [practitioner consensus].

SS-31 (elamipretide, brand Forzinity) is FDA-approved in the United States for Barth syndrome under accelerated approval Elamipretide: The first cardiolipin-directed mitochondrial therapeutic for Barth syndrome approved under accelerated approval+1. It remains investigational for all other indications. Internationally, it is not approved by EMA or other major regulators as of this corpus Elamipretide: First Approval. It is not listed on the WADA Prohibited List, but athletes should verify status before use Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Importing unapproved versions for research may raise legal issues Elamipretide: First Approval.

The most common side effects with SS-31 are injection-site reactions, including redness, itching, swelling, and bruising Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives+1. Less frequent effects include headache, nausea, dizziness, and fatigue Elamipretide: a review of its structure, mechanism of action, and therapeutic potential. Renal function monitoring is advised during extended use Elamipretide: First Approval. Contraindications include known hypersensitivity to elamipretide, and caution is warranted in renal impairment, pregnancy, and lactation Elamipretide: First Approval. Long-term safety data outside Barth syndrome are limited Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives.