Frequently asked questions.

Lots are released against a ≥99% reverse-phase HPLC purity criterion unless otherwise stated on the product page. The actual measured purity for your specific lot is on the COA.

Look up your lot number (printed on the vial) on our batch portal at koipeptides.com/lot/. Each lot has a public page with HPLC chromatogram, LC-MS spectrum, and counterion content.

Both. We run internal HPLC and LC-MS on every lot, then ship a sample to an independent ISO 17025–accredited laboratory for blind retest. We publish both sets of results.

A third-party COA means the analytical work was done by a lab with no commercial interest in the result. It's the only way to verify that the supplier's internal claims hold up. We pay for it on every lot because it's the right way to do it.

It doesn't ship. We re-purify or re-synthesize, and the customer waiting on it gets a heads-up call before any timeline slips. Honest communication beats a quiet rescheduling.

Lyophilized peptides should be stored at -20°C in their original sealed vial. Once reconstituted, store aliquots at -80°C to preserve activity. Avoid repeated freeze-thaw cycles.

Most lyophilized peptides are stable for at least 24 months at -20°C. The exact dating is on the COA, and we publish stability data on our blog for the most-ordered compounds.

Sterile bacteriostatic water is suitable for most peptides. Hydrophobic sequences may require a small percentage of acetic acid or DMSO. Each product page lists a recommended reconstitution buffer.

The label shows the net peptide mass. Counterions (acetate, TFA) and residual water can add 5–20% to the gross weight. The COA reports both net and gross values.

Email the sequence (single-letter code), required scale, target purity, and any modifications to [email protected]. You'll have a scoped quote within one business day.

Linear sequences ≤30 amino acids typically run 10–14 business days. Modified or longer sequences run 14–21 days. Cyclic and stapled peptides run case-by-case.

N-terminal acetylation, C-terminal amidation, PEGylation, lipidation, phosphorylation, biotinylation, fluorescent labeling (FAM/TAMRA/FITC/Cy3/Cy5), and isotope labeling. Stapled and head-to-tail cyclic peptides are available case-by-case.

We'll tell you upfront. If the sequence has a known synthesis-difficulty risk, our chemists will flag it during the quote stage and propose an approach (microwave-assisted SPPS, pseudoproline insertion, or fragment condensation).

Yes. We sign mutual NDAs as a default for any custom synthesis project. Send your standard form or use ours.

No. All Koi Peptides products are sold strictly for in-vitro research and laboratory use. They are not drugs, supplements, cosmetics, or food, and they are not intended for human or veterinary administration.

Customers must be legitimate research professionals — academic researchers, commercial scientists, or institutional buyers. We may request institutional verification for orders above defined thresholds or for restricted compounds.

No. We are an RUO supplier. For GMP-grade material destined for clinical use, we recommend partnering with a registered cGMP CDMO; we'd rather refer you out than misrepresent our scope.

Some peptides are subject to export controls or institutional restrictions. We follow US export regulations strictly and may request end-use documentation for sensitive sequences.

Major credit cards, ACH, and wire transfer. Verified institutional buyers can apply for net-30 terms.

Yes. Volume pricing for academic labs, CROs, and biotech research teams is available through our wholesale program. Reach out to [email protected].

Absolutely. Add the items to a quote request from any product page, or email us. Quotes are returned within one business day and lock pricing for 30 days.

If a peptide doesn't match its COA on independent retest, we replace it or refund the order. We do not accept returns of opened vials for unrelated reasons — this is industry standard for research chemicals.