Elamipretide, the drug sold as "SS-31," has been FDA-approved as Forzinity since September 19, 2025, so research SS-31 sold for human use is an unapproved copy of an approved drug. Nine of the ten vendors we rate list it, and Peptide Plugs documents its testing best, with Freedom Diagnostics lots, purity and measured content for both sizes and the lowest 50 mg price per mg among them ($2.20). Blank Peptides and Alpha Pro Peptides also show recent lots. FDA warning letters dated August 24, 2026 named SS-31 at four sellers, two of which are in our price index.
Notice: Research peptides are sold for in-vitro laboratory research only. They are not FDA-approved, not for human or animal consumption, and this page is not medical advice.
Our criterion: an SS-31-specific COA with a named lab and lot number beats a generic "third-party tested" claim. We don't test products; we check what each vendor publishes.
Regulatory status of SS-31
- FDA approval: FDA approved elamipretide as Forzinity on September 19, 2025, under accelerated approval, for improving muscle strength in people with Barth syndrome weighing at least 30 kg (FDA Drug Trials Snapshot; review documents). Continued approval depends on a confirmatory trial. Research-labeled SS-31 is not Forzinity, and selling it for human use makes it an unapproved copy of an approved drug.
- Compounding lists: SS-31 isn't on FDA's Category 2 page or the 503A categories list, and it hasn't been part of any Pharmacy Compounding Advisory Committee review.
- Warning letters: FDA warning letters dated August 24, 2026 (posted September 1) named SS-31 among unapproved new drugs at Royal Peptides, Peptide Partners, Tex Peptides and Peak Performance Peptides. The letters quote vendor copy such as "mitochondria-targeted tetrapeptide."
- WADA: the 2026 Prohibited List doesn't name SS-31 or elamipretide (2026 list text). S0 covers substances with no government approval, which arguably no longer fits elamipretide; its status isn't confirmed, so check with WADA or USADA.
- DEA: not on DEA's controlled substances list, August 2026 edition.
More: are peptides legal? and FDA peptide regulation in 2026.
SS-31 by vendor
Single-vial prices shown on October 20, 2026, including any displayed sale price. $/mg is price divided by labeled mg. Vendors appear in our editors' order, which isn't sorted by score.
| Vendor | Stocks it | Vial size(s) | Price | $/mg | SS-31 COA / lab | Review |
|---|
| American Peptides | Yes | 10, 30, 50 mg | $70 / $160 / $215 | $7.00 / $5.33 / $4.30 | Lots SS31-10-0803, SS31-30-0803; lab not shown | Review |
| NextGenPeps | Yes | 10 mg | $79 | $7.90 | Janoshik, Apr 30, 2026, 99.941%; lot not shown | Review |
| PSPeptides | Yes | 10 mg, 50 mg | $64.99 / $179.99 | $6.50 / $3.60 | Batch NAD-0036048 (10 mg), NAD-0037971 (50 mg); lab not shown | Review |
| Blank Peptides | Listed, out of stock | 10 mg | $70 | $7.00 | Horizon Analytical, lot 5133749, Jul 31, 2026, 99.48% | Review |
| Ascension Peptides | Yes | 10 mg | $79.99 | $8.00 | Kovera Labs, batch 40-05260628, May 26, 2026 | Review |
| Peptide Plugs | Yes | 10 mg, 50 mg | $40 / $110 | $4.00 / $2.20 | Freedom Diagnostics, lots 7208100C-DK and 160-450L-DK | Review |
| Swiss Chems | Yes | 5 mg, 10 mg | $41.95 / $74.95 | $8.39 / $7.50 | No SS-31 report captured; lab and lot not shown | Review |
| Licensed Peptides | Yes | 10 mg, 50 mg | $99.99 / $244.99 | $10.00 / $4.90 | Report images, codes V260202-26 and V260423-7; lab not shown | Review |
| Alpha Pro Peptides | Yes | 10 mg, 50 mg | $65.99 / $125.99 | $6.60 / $2.52 | Lots Alph2608131149 and Alph2608131147, Aug 20, 2026; lab not shown | Review |
Peptide Confidential didn't list SS-31 on October 20, 2026.
Notes on the table:
- American Peptides: the product page sells 10, 30 and 50 mg and links three certificate PDFs (10 mg). Its COA page lists a lot per size; the text we read showed no lab or purity.
- NextGenPeps: the product page is titled "SS-31 Peptide (Elamipretide)." Its COA library lists a Janoshik report dated April 30, 2026 at 99.941%, with no endotoxin test and no lot.
- PSPeptides: the product page gives the sequence as D-Arg-dimethylTyr-Lys-Phe and links an August 10 mg certificate and an October 50 mg certificate, each with heavy metals, endotoxin and sterility reports. Its other product pages we checked link a "Dosage protocol" section, which we count against the vendor.
- Blank Peptides: the product page showed the 10 mg vial out of stock. It lists 639.8 g/mol and lot 5133749 at 99.48% (certificate; endotoxin report), and report number 1021406 can be checked on Horizon Analytical's site.
- Ascension Peptides: the product page lists a Kovera Labs batch tested May 26, 2026 (PDF) and an MZ Biolabs batch 40-07250828 tested September 20, 2025. No purity is shown on the page.
- Peptide Plugs: the 10 mg page reports lot 7208100C-DK, tested August 22, 2026: 99.87% purity and 10.56 mg measured, with a seven-test panel (certificate). The 50 mg page headlines lot 160-450L-DK (July 16, 2026, 99.93%, 51.51 mg), while its batch history marks a September 1, 2026 lot, 112450L-DK at 48.24 mg, as current (certificate); ask which lot ships. It also sells a "MitoStack" SS-31 + MOTS-c blend, which this page doesn't cover.
- Swiss Chems: the product page is titled "SS31 (Elamipretide)" and sells 5 and 10 mg vials. We didn't capture an SS-31 report for it, so the lab and lot aren't shown. Its 5 mg vial is the only 5 mg SS-31 listing in our index.
- Licensed Peptides: the product page showed sale prices ($111.10 and $272.21 before discount) and links report images for the 10 mg and 50 mg sizes. The code V260202-26 also appears on its kisspeptin report, so it may be a testing batch rather than a product lot.
- Alpha Pro Peptides: the testing page lists lot Alph2608131149 (10 mg, 99.63%, 11.33 mg) and Alph2608131147 (50 mg, 99.78%, 54.04 mg), both reported August 20, 2026 (50 mg PDF). The 50 mg page also shows an August 8 report for lot 5133749 at 99.48%, the same lot number and purity as Blank Peptides' certificate, which suggests a shared upstream batch. On the 10 mg page, the August 8 lot reads 8032676 while the linked PDF's file name says 9926414.
Cheapest SS-31 across all 44 vendors we track
As of October 20, 2026, 44 vendors in our SS-31 price index list it (69 listings counting multi-vial kits). Per-mg figures below use in-stock single vials only.
- Cheapest per mg overall: GenX Bio, 50 mg for $89 ($1.78/mg).
- Cheapest among vendors that pass our checks (no red flags, COAs published, lot-matched or named lab; 22 vendors): Drexa Labs, 50 mg for $109 ($2.18/mg), then Peptide Plugs, 50 mg for $110 ($2.20/mg), and Alpha Pro Peptides, 50 mg for $125.99 ($2.52/mg). For 10 mg vials, Peptide Plugs' $40 ($4.00/mg) is the lowest among vendors that pass.
- Median: $5.00/mg, with a range of $1.78 to $12.00. Larger vials cost less per mg: 50 mg vials from Peptide Plugs, Alpha Pro, PSPeptides ($3.60/mg) and American Peptides ($4.30/mg) are all below the median.
- Sizes: 10 mg (35 listings) and 50 mg (25) dominate; 5, 15, 25, 30, 39 and 100 mg vials also appear.
- Red flags: Royal Peptides (50 mg at $2.40/mg) and Peptide Partners list SS-31, and FDA's August 24, 2026 letters to both named it. Peptide Pros and Sports Technology Labs also sell SARMs.
Compare sizes side by side with the peptide price comparison tool.
What is SS-31?
SS-31 (elamipretide, formerly MTP-131 and Bendavia) is a synthetic Szeto-Schiller tetrapeptide, D-Arg-Dmt-Lys-Phe-NH2, where Dmt is 2',6'-dimethyltyrosine. It concentrates in the inner mitochondrial membrane and interacts with cardiolipin (mechanism study; review). Unlike most research peptides, it has human trial data, including the TAZPOWER extension in Barth syndrome that preceded its first approval. That approval covers Forzinity, not research-labeled vials.
How to check an SS-31 COA
- Check identity by mass. SS-31's molecular weight is about 640 g/mol (Blank Peptides lists 639.8). The certificate should confirm it by mass spectrometry, not just HPLC purity.
- Look for the modified residues. SS-31 contains D-arginine and dimethyltyrosine (Dmt). A sequence that lists plain Arg or Tyr describes a different peptide, and a mass match alone can't distinguish D-Arg from L-Arg, since both weigh the same.
- Match the lot to the size. Several vendors sell 10 and 50 mg; each size should have its own lot, and the PDF's lot and file name should agree with the listing.
- Compare measured content to the label. Measured SS-31 ranged from 10.56 to 11.33 mg on 10 mg labels and from 48.24 to 54.04 mg on 50 mg labels in the certificates above.
See how to read a peptide COA, the COA checklist and the reconstitution calculator.
Independent test data
Finnrick's SS-31 page showed 20 tests on October 20, 2026, from March 12 to September 17, 2026, across about seven vendors. One example vendor page, for Reta-Peptide, shows three passes and one fail. We couldn't match the public results to the nine vendors above. Every certificate in the table was commissioned by the vendor, which chooses the sample it sends. More on community testing: what is Finnrick?
Vendor links
In our editors' order. Each review covers the vendor's policies, red flags and full testing record.
Bottom line
SS-31 is the one compound on our list with an FDA-approved counterpart, and FDA has already sent warning letters naming it, so research-use labeling matters more here than for most peptides. Among the vendors we rate, Peptide Plugs has the most checkable records and the lowest prices per mg, though its 50 mg page shows two different "current" lots. Blank Peptides has a named lab and lookup code but was out of stock, and Alpha Pro shows recent lots with content but a lot-number mismatch on the 10 mg page. NextGenPeps names Janoshik without a lot, American Peptides shows lots without a lab, and Swiss Chems showed no SS-31 report in our capture. For the full comparison, see best peptide vendors in the USA and third-party tested peptides.
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