SS-31 Research Peptide Guide: Mitochondria & Cardiolipin | Palmetto Peptides

SS-31 Research Peptide: Complete Guide to Mitochondrial Targeting, Cardiolipin Binding, and Laboratory Applications

Research Notice: This article covers research on SS-31 research peptide and MOTS-C research peptide — available from Palmetto Peptides for laboratory use only.

Research Use Only Disclaimer: All peptides listed on this page are sold exclusively for in vitro and legitimate laboratory research purposes. They are not intended for human consumption, veterinary use, or any clinical application. The information in this article is for scientific and educational reference only and does not constitute medical advice. All research use must comply with applicable federal, state, and institutional regulations. Palmetto Peptides complies fully with all applicable FDA guidelines.

Research Disclaimer: SS-31 is sold by Palmetto Peptides strictly as a research compound for in vitro and laboratory use only. It is not intended for human or veterinary consumption, administration, or therapeutic use.

SS-31 is a tetrapeptide research compound with the sequence D-Arg-Dmt-Lys-Phe-NH2 — the most widely studied member of the Szeto-Schiller peptide family, with a unique mechanism of action centered on mitochondrial accumulation and cardiolipin binding in laboratory models. Researchers can order SS-31 research peptide from Palmetto Peptides with lot-specific HPLC purity documentation, mass spectrometry identity confirmation, and peptide content data for every batch.

Last Updated: April 21, 2026 | Reading Time: Approximately 7 minutes | Author: Palmetto Peptides Research Team

Quick Answer

SS-31 is a tetrapeptide research compound with the sequence D-Arg-Dmt-Lys-Phe-NH2 — the most widely studied member of the Szeto-Schiller peptide family, with a unique mechanism of action centered on mitochondrial accumulation and cardiolipin binding in laboratory models.

What Is SS-31 Research Peptide?

SS-31 (also known as elamipretide or MTP-131 in clinical research contexts) is a synthetic tetrapeptide developed by Dr. Hazel Szeto and Dr. Peter Schiller in the early 2000s. It was originally designed as a cell-permeable antioxidant, but subsequent research revealed that it selectively accumulates in mitochondria and binds to cardiolipin — the signature phospholipid of the inner mitochondrial membrane. This discovery repositioned SS-31 as one of the most mechanistically specific mitochondria-targeted research tools available.

For broader context on mitochondrial biology relevant to SS-31 research, see our guides on MOTS-C mitochondrial peptide research and mitochondrial function and aging research.

Molecular Identity: Sequence, Formula, and Key Properties

Sequence

D-Arg-Dmt-Lys-Phe-NH2

Molecular Formula

C32H49N9O5

Molecular Weight

~639.80 g/mol

Net Charge (pH 7.4)

+3

CAS Number

736992-21-5

Also Known As

Elamipretide, MTP-131, Bendavia

Non-Standard Residue

2',6'-Dimethyltyrosine (Dmt) at position 2

For a deep-dive on the chemical structure: SS-31 Chemical Structure: Sequence, Formula, and Molecular Weight.

Mechanism of Action in Laboratory Models

Step 1: Mitochondrial Accumulation

SS-31's net +3 charge at physiological pH, combined with the large negative membrane potential of the inner mitochondrial membrane (approximately -180 mV), creates a thermodynamic driving force for cationic compounds to concentrate inside mitochondria. SS-31 accumulates in mitochondria-rich compartments at concentrations estimated to be orders of magnitude above the bulk extracellular level.

Step 2: Cardiolipin Binding

Once at the inner membrane, SS-31 binds to cardiolipin via the aromatic-cationic interaction mechanism — electrostatic anchoring of cationic residues (D-Arg, Lys) to cardiolipin's anionic phosphate groups, combined with insertion of aromatic residues (Dmt, Phe) into the lipid acyl chain region. This localized binding distinguishes SS-31 from non-targeted antioxidant compounds. Full mechanism detail: SS-31 and Cardiolipin Interactions: What Laboratory Models Show.

Step 3: Downstream Effects in Cell-Based Models

In published in vitro studies, SS-31 treatment in stressed cell models has been associated with changes in cytochrome c behavior, mitochondrial membrane potential, electron transport chain activity, and ATP production. For assay design guidance: SS-31 In Vitro Mitochondrial Function Assay Applications.

Research Applications

SS-31 is used as a tool compound in laboratory models studying:

Mitochondrial bioenergetics (Seahorse XF OCR analysis)

Membrane potential (JC-1, TMRE fluorescence)

Mitochondrial superoxide and ROS biology (MitoSOX)

Cardiolipin biology and membrane dynamics

Ischemia-reperfusion model systems in cardiac and renal cell lines

Oxidative stress in neuronal cell models

Mitochondria-mediated apoptosis pathway research

Related research context: NAD+ and mitochondrial biogenesis research, anti-aging and longevity peptide research, cellular health research.

Purity and Quality Standards

For rigorous in vitro research, SS-31 should meet the following minimum quality standards:

HPLC purity: at least 95% for standard assays; 98% or above for quantitative or publication-quality work

MS identity confirmation: lot-specific ESI-MS or MALDI-TOF data confirming MW approximately 639.80 g/mol

Peptide content: reported separately from HPLC purity, accounting for TFA counterion and water

Lot-specific COA with actual HPLC chromatogram included

For full QC guidance: HPLC Purity and Quality Control Standards for SS-31 and Analytical Methods for Verifying SS-31 Identity and Purity In-Lab.

Reconstitution and Storage

SS-31 is highly water-soluble (soluble at 10 mM or above in sterile water or PBS) due to its +3 net charge. Reconstitute in sterile ultrapure water or PBS pH 7.4. Avoid DMSO. Store lyophilized powder at -20C or -80C desiccated dark; reconstituted stocks in single-use aliquots at -80C. Maximum 3 freeze-thaw cycles. Full protocol: SS-31 Reconstitution and Long-Term Storage Protocols. Buffer formulation guidance: SS-31 Solubility, Stability, and Buffer Formulation Guidelines.

Purchasing SS-31 Research Peptide

Palmetto Peptides offers SS-31 research peptide with lot-specific HPLC and MS documentation. Key criteria to verify with any supplier: lot-specific COA, actual chromatogram (not just a number), MS identity confirmation, and peptide content percentage. Detailed guidance: Buying Guide: How to Select High-Quality SS-31 from Reputable Lab Suppliers. Order SS-31 research peptide from Palmetto Peptides here.

Complete SS-31 Research Cluster: All Supporting Articles

Chemical Structure: Sequence, Formula, Molecular Weight

Structural chemistry reference

Cardiolipin Interactions: What Lab Models Show

Mechanism deep-dive

In Vitro Mitochondrial Function Assays

Assay design and protocols

Reconstitution and Long-Term Storage Protocols

Lab handling procedures

SS-31 vs Other Szeto-Schiller Peptides

Analog comparison

HPLC Purity and Quality Control Standards

COA interpretation

Synthesis and Manufacturing Processes

Production overview

Solubility, Stability, and Buffer Formulation

Formulation guidance

History and Development of SS Peptides

Research origins

Buying Guide: Selecting a Reputable Supplier

Purchasing guidance

Analytical Methods for Identity and Purity Verification

In-lab QC methods

SS-31 FAQ for Scientists

Common questions answered

Frequently Asked Questions

What is SS-31 research peptide?

SS-31 is a synthetic tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH2. It is studied in laboratory settings for its mitochondria-targeting and cardiolipin-binding properties. Also known as elamipretide or MTP-131. Not approved for human or veterinary use — sold strictly as a research compound.

What does SS-31 do in mitochondrial research models?

In laboratory models, SS-31 accumulates in mitochondria driven by the inner membrane electrochemical potential, then binds cardiolipin via electrostatic and aromatic interactions. This has been associated in in vitro studies with changes in cytochrome c behavior, electron transport chain activity, and mitochondrial membrane potential.

What is the molecular weight of SS-31?

Approximately 639.80 g/mol. Molecular formula: C32H49N9O5. Monoisotopic mass: approximately 639.37 g/mol.

Is SS-31 approved for human use?

No. SS-31 (elamipretide) has not received FDA approval for any human therapeutic indication. It is available only as a research compound for qualified in vitro and laboratory use.

What purity grade should SS-31 have for research?

At least 95% HPLC purity for standard in vitro assays. 98% or above recommended for quantitative, dose-response, or publication-quality research. Always request a lot-specific COA with HPLC chromatogram and MS identity data.

How should SS-31 be stored?

Lyophilized SS-31 at -20C or -80C in desiccated dark environment. Reconstituted stocks at -80C in single-use aliquots, light-protected. Working solutions at 4C used within 24-48 hours.

SS-31 Research Cluster

Analytical Methods for Verifying SS-31 Research Peptide Identity and Purity in the Lab

Buying Guide: How to Select High-Quality SS-31 Research Peptide from Reputable Lab Suppliers

History and Development of Szeto-Schiller SS Peptides: The Research Origins of SS-31

HPLC Purity Analysis and Quality Control Standards for SS-31 Research Peptides

Laboratory Applications of SS-31 Research Peptide in In Vitro Cellular Mitochondrial Function Assays

Reconstitution and Long-Term Storage Protocols for SS-31 Research Peptide in the Laboratory

SS-31 Research Peptide and Cardiolipin Interactions: What Laboratory Mitochondrial Models Show

SS-31 Research Peptide FAQ for Scientists: Common Laboratory Questions Answered

SS-31 Research Peptide Solubility, Stability, and Buffer Formulation Guidelines for Experiments

SS-31 vs Other Szeto-Schiller Peptides: Key Differences for Mitochondrial Research

Synthesis and Manufacturing Processes for High-Purity SS-31 Research Peptide

The Chemical Structure of SS-31 Research Peptide: Sequence, Molecular Formula, and Molecular Weight Explained

SS-31 (Elamipretide) 2026 Research Update: Latest Mitochondrial Protection Findings

SS-31 and NAD+ Mitochondrial Research Stack: Combining Elamipretide and NAD Precursors

MOTS-C and SS-31 Research Stack: Metabolic and Mitochondrial Protection Combinations

Mitochondrial-Targeted Peptides: A Research Overview of SS-31, MOTS-C, and NAD+

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