SS-31: Common Questions and What the Literature Says

The fasting question, answered directly

The most common search that brings readers to this topic is whether SS-31 needs to be taken on an empty stomach. The plain answer from the published record is that no study has addressed it. Across the peer-reviewed papers reviewed for this page — clinical trials, mechanistic work, and preclinical animal and cell studies — fasting status, meal timing, and food intake were never reported as study variables, inclusion criteria, or pharmacokinetic modifiers. There is no trial arm comparing fasted and fed administration, and no publication stating a food effect in either direction.

There is a structural reason for that silence. SS-31, developed clinically as elamipretide, was given by subcutaneous injection in the human trials described below. A subcutaneous route does not involve the stomach or intestine, so gastric contents are not part of the absorption pathway in the way they are for an orally swallowed drug. Questions about fasting typically arise for oral compounds, where food can slow gastric emptying or bind the molecule. The published elamipretide literature simply never generated that dataset because it never studied an oral formulation in the trials summarised here.

This page is for educational purposes only and is not medical advice; consult a licensed physician about any health decision. Nothing here describes a protocol, and no compound discussed is characterised as safe or effective for personal use.

What SS-31 (elamipretide) is, according to the literature

A 2025 review in International Journal of Molecular Sciences described elamipretide as a small aromatic-cationic tetrapeptide that concentrates in the inner mitochondrial membrane and associates with cardiolipin, a phospholipid central to cristae structure and electron transport chain organisation (PMID 39940712). Researchers in that review framed the molecule's therapeutic rationale around restoring mitochondrial bioenergetics rather than acting on a conventional receptor. A separate 2022 review in Heart Failure Reviews covered the same mitochondrial-targeting premise in the context of cardiac and age-related disease (PMID 35037146).

The mechanistic picture has been refined since. A 2020 study in PNAS mapped the mitochondrial protein interaction landscape of SS-31 and reported that the peptide interacted with a set of mitochondrial proteins beyond cardiolipin alone, broadening the earlier single-lipid model (PMID 32554501). In 2024, a genome-wide CRISPR screen published in JASN identified phospholipid scramblase 3 as a biological target of SS-31, which the authors presented as a discrete molecular handle for the drug's mitoprotective activity (PMID 38530359). None of these mechanistic papers involved oral dosing or dietary state.

How the compound was administered in published studies

Route matters more than meal timing in this literature, and it is worth laying out what each study actually did.

Because cell-culture and injection studies do not involve digestion, the fasted-versus-fed distinction has no experimental meaning in most of this body of work. Readers searching for a food rule are, in effect, asking a question the field has not posed.

What the human trials reported

Primary mitochondrial myopathy

MMPOWER-3, published in Neurology in 2023, was a randomised, double-blind, placebo-controlled trial in individuals with primary mitochondrial myopathy. The study administered elamipretide 40 mg per day subcutaneously over 24 weeks, and researchers reported that the trial did not meet its primary efficacy endpoints of six-minute walk test distance and total fatigue score compared with placebo (PMID 37268435). That negative primary result is an important counterweight to enthusiastic secondary summaries of the peptide, and it came from the largest controlled trial in the set.

Barth syndrome

The TAZPOWER open-label extension, published in Genetics in Medicine in 2024, followed patients with Barth syndrome for 168 weeks on daily subcutaneous elamipretide 40 mg. Researchers reported improvements in functional and cardiac measures sustained across the extension period, alongside a safety profile dominated by injection-site reactions (PMID 38602181). A 2022 commentary in Heart Failure Reviews discussed elamipretide in Barth syndrome cardiomyopathy in terms of gradual restoration of mitochondrial energy production rather than rapid symptomatic change (PMID 34623544).

Regulatory status

A 2026 Drugs article described elamipretide's first regulatory approval, with Barth syndrome as the approved indication and subcutaneous injection as the administration route (PMID 41335372). Approval of a specific product for a specific rare disease is a narrow regulatory fact and does not extend to research-grade material sold for laboratory use, which carries research-use-only status and has not been evaluated for human administration.

Preclinical findings the literature reports

Animal and cell work makes up most of the SS-31 record. In a 2019 mouse study in the Journal of Neuroinflammation, researchers reported that SS-31 improved mitochondrial dysfunction and reduced synaptic and memory impairment induced by lipopolysaccharide (PMID 31747905). A 2026 study in Neurotherapeutics examined post-cardiac-arrest brain injury and reported that SS-31 inhibited microglial ferroptosis and shifted microglial polarisation in that model (PMID 41136322).

Ferroptosis appears again in cardiac work. A 2025 paper in Biomedicine & Pharmacotherapy tested an SS-31-conjugated ferrostatin-1 construct in hypoxia/reoxygenation cardiomyocytes and reported that the mitochondria-targeted delivery reduced ferroptotic injury in those cells (PMID 39848110). In skeletal biology, a 2025 study in Organogenesis reported that SS-31 acted on NOS2 to enhance osteogenic differentiation in aged bone marrow stromal cells by restoring mitochondrial function (PMID 40570323).

These are model-system findings. They describe what happened in mice, rats, or cultured cells under defined laboratory conditions, and the published papers do not extrapolate them to healthy humans, to oral use, or to any particular schedule relative to meals.

Adverse Events: What Studies Report

The clearest human safety information comes from the two trials above. In MMPOWER-3, researchers reported injection-site reactions as the most frequently observed adverse event among participants receiving subcutaneous elamipretide, and the study described the overall tolerability profile alongside its negative primary endpoint result (PMID 37268435). The 168-week TAZPOWER extension similarly reported injection-site reactions as the dominant adverse event category over long-term daily subcutaneous administration, with the authors characterising the extension safety data as consistent with earlier trial phases (PMID 38602181).

The 2026 approval summary reviewed the safety and efficacy basis for the regulatory decision in Barth syndrome (PMID 41335372). No paper in this set reported gastrointestinal adverse events attributable to food interaction, because no paper studied administration in relation to food.

Questions the literature has not answered

• Fasted versus fed administration. Not studied. No comparative arm, no pharmacokinetic food-effect analysis in the papers reviewed here.
• Oral bioavailability. The trials summarised above used subcutaneous injection (PMID 37268435, PMID 38602181); an oral route was not the subject of these publications.
• Time of day. No chronobiology or morning-versus-evening comparison appears in this literature.
• Use in healthy adults. The controlled human trials enrolled patients with defined mitochondrial disease, not healthy volunteers seeking performance or longevity outcomes.
• Combination with other compounds. Beyond the engineered SS-31–ferrostatin construct tested in cells (PMID 39848110), the reviewed papers did not evaluate combinations.

How to read the gap

Absence of evidence is not a finding of safety or of irrelevance. When a question like fasting has never been tested, the honest description is that the data do not exist, not that food "does not matter." Reviews of elamipretide have consistently framed the molecule around mitochondrial membrane targeting and cardiolipin interaction (PMID 39940712, PMID 35037146), and the mechanistic work has moved toward specific protein targets (PMID 38530359). None of that work supplies a dietary rule.

The practical consequence for anyone reading study summaries is to check the route first. A great deal of online guidance about peptide timing is transposed from oral supplements and does not map onto injected molecules studied in rare-disease populations. Readers evaluating claims about SS-31 can reasonably ask which paper the claim came from, what species was studied, what route was used, and whether the endpoint was met — MMPOWER-3 is a reminder that a plausible mechanism and a positive trial are not the same thing (PMID 37268435).

References

• Elamipretide (SS-31) improves mitochondrial dysfunction, synaptic and memory impairment induced by lipopolysaccharide in mice (Journal of Neuroinflammation, 2019)
• Mitochondrial protein interaction landscape of SS-31 (PNAS, 2020)
• Elamipretide for Barth syndrome cardiomyopathy: gradual rebuilding of a failed power grid (Heart Failure Reviews, 2022)
• Targeting mitochondrial dysfunction with elamipretide (Heart Failure Reviews, 2022)
• Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial (Neurology, 2023)
• Genome-Wide CRISPR Screen Identifies Phospholipid Scramblase 3 as the Biological Target of Mitoprotective Drug SS-31 (JASN, 2024)
• Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER (Genetics in Medicine, 2024)
• SS-31@Fer-1 Alleviates ferroptosis in hypoxia/reoxygenation cardiomyocytes via mitochondrial targeting (Biomedicine & Pharmacotherapy, 2025)
• Elamipretide: A Review of Its Structure, Mechanism of Action, and Therapeutic Potential (International Journal of Molecular Sciences, 2025)
• SS-31 Targets NOS2 to Enhance Osteogenic Differentiation in Aged BMSCs by Restoring Mitochondrial Function (Organogenesis, 2025)
• SS-31 improves post-cardiac arrest brain injury by inhibiting microglial ferroptosis and polarization (Neurotherapeutics, 2026)
• Elamipretide: First Approval (Drugs, 2026)