Peptide LibrarySS-20
SS-20 is a mitochondria-targeted tetrapeptide in the Mitochondrial Peptide class. Like other Szeto-Schiller peptides, SS-20 concentrates in the inner mitochondrial membrane in a membrane-potential-independent manner. Unlike elamipretide it does not carry the dimethyltyrosine residue responsible for cardiolipin binding and radical scavenging, and reported effects on mitochondrial morphology and bioenergetics appear to proceed through a different mechanism.
For research use only.
Key Facts
- CAS
- 736992-19-1
- Molecular Weight (MW)
- 595.7 g/mol
- Half-life
- —
- FDA status
- Not Approved
- Evidence level
- Insufficient Evidence
- Human dose established
- No
- Administration Route
- Not established in humans
- Frequency
- Not established in humans
- Last updated
- Nov 7, 2026
- Reviewed
- Nov 7, 2026
Research summary
Mitochondria-targeted tetrapeptide from the same Szeto-Schiller series as elamipretide, distinguished by lacking the dimethyltyrosine residue that gives elamipretide its cardiolipin affinity. Not FDA-approved; preclinical only.
Research evidence
- Regulatory review (FDA label)None in reviewed sources
- Controlled human trialsNone in reviewed sources
- Early or uncontrolled human studiesNone in reviewed sources
- Lab & animal studies2 reviewed sources
How it works
Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess.
Peptide Library's SS-20 profile summarises 3 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
SS-20 dosage: no established human dose
SS-20 has no established human dosage. It is a mitochondria-targeted tetrapeptide (Phe-D-Arg-Phe-Lys-NH2) from the same Szeto-Schiller series as elamipretide (SS-31), and it has only been given to animals. In rats it was injected into the abdominal cavity at 3 mg/kg before and during a heart-attack model.
No established human dosage.
Human clinical evidence: None identified.
Preclinical research: SS-20 is used in research mainly as a comparison peptide: unlike elamipretide it has no dimethyltyrosine and does not scavenge reactive oxygen species. Its in vivo work is in rodents, in mg/kg amounts that do not convert to a human dose. No human study of SS-20 was found in PubMed or ClinicalTrials.gov.
Animal dosing is not converted into a human dose anywhere on this page. Where research figures appear below, they are reported as studied, not recommended.
| Human dosing established | No |
|---|---|
| Route | Not established in humans |
| Evidence level | Insufficient Evidence |
| Last reviewed | 2026-11-07 |
Preclinical and analog research
Not human dosing evidence. Listed for completeness and never extrapolated to a human dose.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| Preclinical — SS-20 in rat myocardial ischaemia-reperfusion (2007)Preclinical · Animal study | Rats (n=8 per group) | 3 mg/kg (non-human) | Intraperitoneal | Two doses: 30 minutes before coronary ligation and 5 minutes before reperfusion | Single experiment | Smaller infarct relative to the area at risk, less lipid peroxidation and fewer arrhythmias than saline | Potent mitochondria-targeted peptides reduce myocardial infarction in rats. Coron Artery Dis. 2007. |
| Preclinical — SS-20 and oxaliplatin-induced nerve damage in mice (2018)Preclinical · Animal study | Mice given weekly oxaliplatin | Not stated in the indexed abstract (non-human) | Not stated in the indexed abstract | Continuous administration | — | Protection against neuropathic pain and loss of skin nerve fibres | Protective Effect of a Mitochondria-Targeted Peptide against the Development of Chemotherapy-Induced Peripheral Neuropathy in Mice. ACS Chem Neurosci. 2018. |
Where sources disagree
- SS-20 and elamipretide (SS-31) are different molecules. Elamipretide's approved dose in Barth syndrome, and its trials, are not evidence for SS-20; the elamipretide profile covers that compound.
Reconstitution
These figures are arithmetic only — they convert a vial and a volume into a concentration. They are not a recommendation to take any dose.
Calculate reconstitution & dose →Sequence & molecular data
| Molecular formula | C30H45N9O4 |
|---|---|
| Molecular weight | 595.7 g/mol |
| CAS number | 736992-19-1 |
| PubChem CID | 10008657 |
| FDA UNII | U260G1W6DY |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Like other Szeto-Schiller peptides, SS-20 concentrates in the inner mitochondrial membrane in a membrane-potential-independent manner. Unlike elamipretide it does not carry the dimethyltyrosine residue responsible for cardiolipin binding and radical scavenging, and reported effects on mitochondrial morphology and bioenergetics appear to proceed through a different mechanism. It is used mainly as a comparator that separates cardiolipin-dependent from cardiolipin-independent effects.
Studies
- A mitochondria-targeted idebenone derivative W1a mitigates cerebral ischemia-reperfusion injury by preserving mitochondrial integrity and suppressing neuroinflammation
- Quantifying tetrapeptide SS-20 in rat plasma using hydrophilic interaction liquid chromatography coupled with electrospray ionization tandem mass spectrometry
- Improved mitochondrial targeting effect of HPMA copolymer by SS20 peptide mediation and nonendocytosis pathway
Research statistics
15 PubMed publications · 6.7% human clinical research · 0 registered trials
Counts of published research through 2026-11-01, not evidence that it works. Publications by year, study types and trials · How publications are counted
Regulatory & research status
SS-20 is not an FDA-approved product. It is sold for laboratory research and has no approved medical use.
| FDA status | Not Approved |
|---|---|
| Research status | Research-only compound; no approval pathway listed |
| Availability | Research-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | Research-Only |
How FDA approval, compounding and research-only status differ
Benefits
—
SS-20 side effects
No side effects listed yet for this entry.
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
SS-20: frequently asked questions
What is SS-20?
Mitochondria-targeted tetrapeptide from the same Szeto-Schiller series as elamipretide, distinguished by lacking the dimethyltyrosine residue that gives elamipretide its cardiolipin affinity. Not FDA-approved; preclinical only.
How does SS-20 work?
Like other Szeto-Schiller peptides, SS-20 concentrates in the inner mitochondrial membrane in a membrane-potential-independent manner. Unlike elamipretide it does not carry the dimethyltyrosine residue responsible for cardiolipin binding and radical scavenging, and reported effects on mitochondrial morphology and bioenergetics appear to proceed through a different mechanism.
Is SS-20 FDA approved?
No. SS-20 is not approved by the FDA for any indication and is categorised as research-only. It has not been reviewed for safety or efficacy as a medicine, and published research should be read as investigation rather than established use.
What peptides are similar to SS-20?
Compounds most often compared with SS-20 include MOTS-C, Humanin, Humanin-G (HNG) and Elamipretide (SS-31). They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- A mitochondria-targeted idebenone derivative W1a mitigates cerebral ischemia-reperfusion injury by preserving mitochondrial integrity and suppressing neuroinflammation — Bioorg Chem, 2026External reference
- Quantifying tetrapeptide SS-20 in rat plasma using hydrophilic interaction liquid chromatography coupled with electrospray ionization tandem mass spectrometry — J Chromatogr B Analyt Technol Biomed Life Sci, 2011External reference
- Improved mitochondrial targeting effect of HPMA copolymer by SS20 peptide mediation and nonendocytosis pathway — J Pept Sci, 2019External reference
Related research, comparisons & guides
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Nov 7, 2026 · Version 4
This SS-20 profile is compiled from published literature (3 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
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