Tag Archives: neuroprotection

Research Use Only Notice: SS-31 (Elamipretide) is a research peptide intended for in-vitro and animal research applications only. While it has been studied in clinical trials internationally, it is not FDA-approved as a drug. Nothing in this article constitutes medical advice, treatment recommendation, or guidance for human consumption.

SS-31 — also known as Elamipretide — is a small synthetic peptide that targets the inner mitochondrial membrane through cardiolipin binding. Unlike most research peptides that act on cell-surface receptors, SS-31 acts at the structural level of mitochondria themselves, stabilizing membrane architecture and improving electron transport chain efficiency. This unique mechanism has made SS-31 one of the most actively studied compounds in mitochondrial dysfunction research, with applications spanning cardiac disease models, neurodegeneration research, and broader mitochondrial biology. This complete guide from the chemistry team at OPS Peptide Science walks through what SS-31 is, how the cardiolipin binding mechanism works, and how it complements MOTS-c in mitochondrial research.

For the foundational research-workflow protocols, see our companion guides on how to reconstitute peptides, how to inject peptides, and peptide storage and refrigeration.

What Is SS-31?

SS-31 is a small synthetic peptide designed to selectively accumulate in mitochondria, where it binds cardiolipin — a phospholipid unique to the inner mitochondrial membrane. The “SS” prefix refers to the Szeto-Schiller research lineage where the compound was developed. The compound has also been called Bendavia in some clinical research contexts and Elamipretide as its International Nonproprietary Name (INN).

Key facts about SS-31:

• Chemical class — 4-amino-acid synthetic peptide with modified aromatic residues
• Molecular weight — approximately 640 Da
• Sequence — D-Arg-2′,6′-dimethyltyrosine (Dmt)-Lys-Phe-NH2
• Developer — Stealth BioTherapeutics
• Half-life — approximately 2 hours
• Form — typically supplied as lyophilized powder; reconstituted with bacteriostatic water
• Clinical trial status — has been studied in Phase 2 and 3 trials for cardiovascular indications; not yet FDA-approved

What distinguishes SS-31 from most research peptides is its mechanism of action. While most peptides work by binding extracellular receptors and triggering downstream signaling cascades, SS-31 crosses cell membranes, accumulates in mitochondria specifically, and acts on the inner mitochondrial membrane structure directly. This is a different mechanistic category than the receptor agonist peptides that dominate most research catalogs.

SS-31 Structure and Chemistry

The SS-31 structure was engineered specifically for mitochondrial targeting:

• D-amino acid at position 1 — D-arginine prevents enzymatic degradation
• Modified tyrosine (Dmt) at position 2 — 2′,6′-dimethyltyrosine provides aromatic character important for mitochondrial accumulation
• Positively charged residues — the arginine and lysine carry positive charges that drive mitochondrial accumulation (mitochondria have a strong negative membrane potential)
• C-terminal amide — protects against C-terminal degradation
• Small size — only 4 amino acids; small enough to cross membranes through passive mechanisms

The combination of small size, positive charge, and aromatic residues makes SS-31 unusually efficient at penetrating cell membranes and concentrating in mitochondria — typically achieving 1000-fold or higher concentrations in mitochondria compared to surrounding cytoplasm.

How SS-31 Works in Research (Cardiolipin Binding Mechanism)

The SS-31 mechanism centers on cardiolipin — a phospholipid found exclusively in the inner mitochondrial membrane. Cardiolipin has several critical functions:

• Stabilizes electron transport chain complexes — Complexes I, III, IV, and V all require cardiolipin for proper assembly and function
• Maintains inner membrane curvature — cardiolipin’s unique structure helps form the cristae folds that increase mitochondrial surface area
• Participates in apoptosis signaling — cardiolipin oxidation triggers cytochrome c release in programmed cell death
• Declines with age and disease — cardiolipin levels and integrity decrease in mitochondrial dysfunction

SS-31 binds cardiolipin and produces several documented effects:

• Membrane stabilization — protects cardiolipin from oxidative damage
• Improved electron transport efficiency — enhances Complex I, III, and IV function in research models
• Reduced ROS production — improved electron flow means less electron leakage and reactive oxygen species generation
• ATP production support — better-functioning electron transport chain produces more ATP per oxygen consumed
• Reduced mitochondrial swelling — protects against permeability transition pore opening

The mechanism is structural rather than signaling-based — SS-31 doesn’t activate or inhibit receptors. It supports the mechanical and chemical environment that mitochondria need to function efficiently. The published SS-31 and Elamipretide research literature on PubMed documents these mechanisms across hundreds of studies.

SS-31 Research Applications

Cardiac Research

The largest body of SS-31 research focuses on cardiac applications. Animal models of heart failure, ischemia-reperfusion injury, and cardiac dysfunction have documented SS-31 effects on cardiac function markers, ejection fraction, and survival endpoints. SS-31 has been studied in human cardiovascular clinical trials internationally — though not yet FDA-approved for cardiac indications. Current trial status is tracked on ClinicalTrials.gov.

Neurodegeneration Research

Mitochondrial dysfunction is implicated in Alzheimer’s, Parkinson’s, and other neurodegenerative diseases. SS-31 research extends into these models — measuring effects on neuronal mitochondrial function, ROS markers, and neurodegeneration progression in animal research.

Mitochondrial Disease Research

SS-31 has been studied in genetic mitochondrial disease models — Barth syndrome, Leber’s hereditary optic neuropathy, and other primary mitochondrial dysfunctions. The cardiolipin binding mechanism is particularly relevant to Barth syndrome, where cardiolipin metabolism is genetically disrupted.

Skeletal Muscle Research

Aging-related muscle dysfunction (sarcopenia) involves declining mitochondrial function. Research has documented SS-31 effects on muscle mitochondrial function, ATP production, and exercise performance markers in animal aging models.

Kidney Research

Renal ischemia-reperfusion injury, acute kidney injury, and chronic kidney disease research models have used SS-31 to study mitochondrial dysfunction contributions to kidney pathology.

Eye Research

Age-related macular degeneration and other retinal diseases involve mitochondrial dysfunction. SS-31 research extends into ophthalmologic models studying mitochondrial protection in retinal cells.

SS-31 vs MOTS-c: Mitochondrial Peptide Comparison

Both SS-31 and MOTS-c target mitochondria, but through completely different mechanisms:

Property	SS-31	MOTS-c
Size	4 amino acids	16 amino acids
Origin	Synthetic design	Mitochondrial DNA encoded
Mechanism	Structural (cardiolipin binding)	Signaling (AMPK activation)
Target	Inner mitochondrial membrane	Multiple cellular pathways
Acute effects	Mitochondrial function within hours	Gene expression over days
Primary research focus	Cardiac, neurodegeneration	Metabolic, insulin sensitivity
Clinical trial history	Yes (cardiovascular)	Limited

The two compounds are complementary rather than redundant. SS-31 provides structural mitochondrial support; MOTS-c provides metabolic and gene expression effects. Research designs studying broad mitochondrial biology sometimes use both compounds to cover different aspects of mitochondrial dysfunction.

SS-31 Dosing in Research Models

SS-31 dosing in published research varies by study design:

• Subcutaneous administration — most common route in animal research
• Intravenous administration — used in cardiac research and clinical trials
• Daily dosing — short half-life supports once-daily protocols in most published research
• Dose ranges — typically reported in mg/kg body weight in animal research; clinical trials have used various dose levels
• Study duration — most pre-clinical studies run 4-12 weeks; some long-term studies extend to 6 months

Research protocols should reference published methodology for the specific model. Cardiac research uses different dosing patterns than neurodegeneration research, and animal model species affect optimal protocols significantly. For broader effect-timeline context, see our guide on how long does it take for peptides to work.

SS-31 Storage and Stability

SS-31 stability follows standard small-peptide patterns, with one notable advantage — its D-amino acid and modified tyrosine residues provide better-than-average stability:

Storage Condition	Form	Stability Window
-80°C	Lyophilized powder	3-5+ years
-20°C	Lyophilized powder	18-24 months
2-8°C	Lyophilized powder	6-12 months
2-8°C	Reconstituted in BAC water	21-28 days
Room temperature	Lyophilized powder	2-4 weeks for transit

For practical storage protocols, see our companion guide on how long do peptides last at room temperature.

How to Identify Quality Research-Grade SS-31

SS-31’s modified amino acids (D-arginine, dimethyltyrosine) make synthesis technically demanding. Quality criteria for research-grade SS-31:

• 99%+ HPLC-MS verified purity — synthesis with modified amino acids produces measurable side products requiring careful purification
• Per-lot Certificate of Analysis — each batch independently tested
• Mass spectrometry identity confirmation — confirms molecular weight matches SS-31 (~640 Da)
• Stereochemistry verification — confirms D-amino acid configurations are correct
• Chain-of-custody documentation — traceable from manufacturer through fulfillment
• Properly lyophilized appearance — clean white cake at the bottom of the vial
• Research-use-only labeling — required by US regulations

At OPS Peptide Science, every SS-31 vial ships with a unique BIOVIRIDIAN COA code. Customers can verify the Certificate of Analysis for their specific lot — confirming purity and identity before opening the vial.

SS-31 Regulatory Status

• Not FDA-approved — clinical trials have been conducted but no US drug approval as of this writing
• Clinical trial history — Phase 2 and 3 trials in cardiovascular indications; mixed results have informed protocol refinement
• Legal as research chemical — sold in the US for in-vitro and animal research under research-use-only labeling
• Not WADA-prohibited as of current updates
• Not DEA-scheduled — no controlled substance status

For the complete legal framework around research peptides like SS-31, see our detailed guide on are peptides illegal.

FAQ

What is SS-31?

SS-31 is a 4-amino-acid synthetic peptide also known as Elamipretide. It targets the inner mitochondrial membrane through cardiolipin binding, stabilizing membrane structure and improving electron transport chain function. It is one of the most actively studied compounds in mitochondrial dysfunction research.

Is SS-31 the same as Elamipretide?

Yes — SS-31 is the original research nomenclature; Elamipretide is the International Nonproprietary Name (INN) used in clinical trials and pharmaceutical contexts. The compound has also been called Bendavia in some clinical research. All three names refer to the same molecule.

How does SS-31 differ from other mitochondrial supplements?

Most mitochondrial supplements (CoQ10, PQQ, NAD+ precursors) work by providing electron transport chain cofactors. SS-31 works differently — it binds cardiolipin in the inner mitochondrial membrane, stabilizing the structural environment that the electron transport chain operates within. The mechanism is structural rather than substrate-based.

Is SS-31 FDA-approved?

No. SS-31 has been studied in Phase 2 and 3 clinical trials for cardiovascular and mitochondrial disease indications but has not received FDA approval. It is sold legally in the US as a research chemical under research-use-only labeling for in-vitro and animal research.

How long does it take SS-31 to show effects in research?

Mitochondrial function effects appear within hours in cell culture research and within days in animal research models. Tissue-level cardiac and neurological endpoints typically require 4-12 weeks of consistent dosing protocols to demonstrate measurable effects.

Can SS-31 be combined with MOTS-c in research?

Combination research is possible because the two compounds act through different mechanisms — SS-31 structurally at the mitochondrial membrane, MOTS-c through AMPK signaling and gene expression. Research designs studying broad mitochondrial biology sometimes use both compounds to cover complementary aspects. Specific combination protocols should be informed by published methodology references.

Where can I buy research-grade SS-31?

Research-grade SS-31 is sold by research peptide suppliers operating under research-use-only labeling. Quality criteria include 99%+ HPLC-MS verified purity, per-lot Certificates of Analysis, mass spectrometry identity confirmation, and verification of D-amino acid stereochemistry. Browse the OPS Peptide Science catalog for verified research-grade SS-31.

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SS-31 represents a distinct category in the research peptide catalog — a structural mitochondrial peptide rather than a receptor-targeting compound. Its cardiolipin binding mechanism enables research applications spanning cardiac dysfunction, neurodegeneration, mitochondrial disease, kidney research, and skeletal muscle biology. Combined with MOTS-c’s signaling-based mitochondrial mechanism, SS-31 forms the structural half of a complementary mitochondrial peptide research pair.

For research-grade SS-31 backed by per-lot Certificates of Analysis and full HPLC-MS purity documentation, browse the OPS Peptide Science catalog, visit the OPS Peptide Science homepage for the full product overview, or verify a specific lot using its COA code.

Author: Shane Straight, Principal Chemist, OPS Peptide Science
Reviewed: Feb 2026