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Nth Peptides
99% Purity GuaranteeEvery batch third-party HPLC & MS verified — or your money backRead the policy
Quality policy

The 99% Purity Guarantee

Every batch we sell is third-party verified by HPLC and mass spectrometry to 99%+ purity. If an independent re-test says otherwise, you get your money back. The complete policy terms are below.

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Third-party HPLC & MS

Every production lot is analyzed by an independent laboratory using reverse-phase HPLC for purity and mass spectrometry for identity confirmation.

Batch-linked COAs

Each lot ships with a Certificate of Analysis referencing its batch number, assay purity, test date, and testing laboratory.

Replace or refund

If an independent re-test shows a lot below 99% purity, we replace the item or refund it in full, including original shipping.

Full policy terms

Last updated: August 2026. These terms form part of our Terms of Service.

1. Scope of the guarantee

  • The 99% Purity Guarantee applies to all research peptides sold by Nth Peptide and listed with a stated purity of 99% or higher.
  • Purity is measured as chromatographic area percent by reverse-phase HPLC at the wavelength stated on the Certificate of Analysis for the applicable lot.
  • Peptide content (net peptide by weight) is a separate specification from chromatographic purity and is not covered by this guarantee unless expressly stated on the product page.

2. Testing methodology

  • Identity is confirmed by mass spectrometry against the theoretical molecular weight of the listed sequence, within standard instrument tolerance.
  • Testing is performed by independent analytical laboratories that are not owned or controlled by Nth Peptide.
  • Certificates of Analysis are published in our COA library and are searchable by product and batch number.

3. Eligibility

  • The claimant must be the original purchaser and provide the order number and the batch number printed on the vial label.
  • Claims must be submitted within 30 days of delivery.
  • Vials must have been stored per the storage conditions listed on the product page and COA. Material stored outside those conditions, reconstituted, repackaged, or transferred to another container is not eligible.
  • Unopened vials from the same lot must be available for return so the lot can be independently re-tested.

4. How to file a claim

  • Contact us through the contact page with your order number, batch number, and the analytical report you are relying on.
  • Independent re-test results must come from an accredited third-party laboratory and must include the raw chromatogram and method parameters.
  • We will arrange prepaid return shipping for the remaining sealed vials of the affected lot.
  • Claims are reviewed within 10 business days of our receipt of the returned material and supporting documentation.

5. Remedies

  • If the lot is confirmed below the stated purity, you may choose a full refund of the purchase price or a replacement from a compliant lot.
  • Original and return shipping costs are reimbursed on confirmed claims.
  • Where a lot is confirmed off-spec, the entire lot is quarantined and removed from sale, and affected customers of that lot are notified.
  • Our total liability under this guarantee is limited to the amount paid for the affected product. Third-party testing fees are not reimbursed unless agreed in writing in advance.

6. Exclusions

  • Degradation resulting from improper storage, temperature excursions after delivery, repeated freeze-thaw cycles, or contamination during handling.
  • Results generated from reconstituted material, since solvent choice, concentration, and handling are outside our control.
  • Custom synthesis orders and clearance or research-surplus items marked with a purity specification below 99%.
  • Any use of the material outside of controlled laboratory research.

7. Research use only

  • All products are sold strictly as laboratory research chemicals. They are NOT for human or animal consumption, and are not drugs, foods, cosmetics, or medical devices.
  • This guarantee concerns analytical specification only and is not a representation of safety, efficacy, or fitness for any therapeutic purpose.
  • Purchasers are responsible for compliance with all applicable laws and institutional requirements governing the handling of research materials.

Questions about a specific lot? Search the COA library or contact our quality team.