SigmaStacks
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Certificates are published per lot as assays complete. Email us with the lot number on your vial for any lot not yet posted.

Refund & Returns Policy

30-day money-back guarantee. If you are not satisfied, contact us within 30 days of delivery to arrange a return and refund. Email [email protected] with your order number to start.

Purity guarantee

We guarantee a minimum purity of 99% on every vial we sell. If independent HPLC testing of your vial comes back below 99%, we will replace the vial or refund it in full.

How to make a claim

  1. Have your vial tested by one of the independent analytical laboratories listed below. The test must include an HPLC purity assay.
  2. Email [email protected] within 30 days of delivery with your order number, the lot number printed on the vial, and the laboratory’s full report.
  3. If the measured purity is below 99%, we replace or refund — your choice — within 5 business days of receiving the report.

Accepted laboratories

  • Janoshik Analytical — Czech Republic · janoshik.com · the most widely used independent peptide-testing lab in the research community
  • Ethos Analytics — Phoenix, Arizona, USA · ethosanalytics.io · ISO/IEC 17025 accredited
  • Vanguard Laboratory — Olympia, Washington, USA · vanguardlaboratory.com · ISO/IEC 17025:2017 accredited
  • ACS Laboratory — USA · acslabtest.com · ISO/IEC 17025 accredited
  • MZ Biolabs — Tucson, Arizona, USA · mzbiolabs.com · widely used for HPLC purity and mass-spec identity

Reports from any laboratory that is ISO/IEC 17025 accredited for HPLC analysis are also accepted; other laboratories are considered case by case. The cost of testing is borne by the customer.

Damaged or incorrect orders

Report within 7 days of delivery with photos and we will replace or refund the affected items.

What is not returnable

  • Opened or reconstituted vials cannot be returned, for research-integrity and safety reasons.
  • We do not provide refunds for misuse of a product or use contrary to our Terms.

Return shipping

Except where an item is defective or shipped in error, return shipping is the buyer’s responsibility and is not included in the refunded amount.

Non-deliverable / restricted-jurisdiction orders

Orders that cannot be delivered, or that are destined for a restricted jurisdiction, are cancelled and refunded (less any shipping already incurred).

How refunds are issued

Refunds are issued to the original payment method used for the order. Once we process a refund, your bank or card issuer typically takes 5–10 business days to post it to your account.

All products are for research use only. Not for human consumption.

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