Questions, answered.
Every question here gets a direct answer first and the reasoning underneath. Where a question involves another laboratory, the figures come from that laboratory's own published information on the date shown. Where it involves us, we say what we do and what we do not measure. Questions that reach us by email get added here rather than answered privately.
Certificates
Certificates — 12 questions
- What is a certificate of analysis for peptides?
- Can a vendor fake a certificate of analysis?
- How do I verify a peptide certificate of analysis?
- Why does my CoA say presumptive identity?
- What does 99% purity actually mean on a peptide test?
- Is chromatographic purity the same as peptide content?
- What is net peptide content?
- Why does my CoA not mention water content?
- What is the difference between HPLC purity and mass balance?
- Should a certificate of analysis name the analyst?
- How long should a laboratory keep my sample?
- What does research use only mean on a peptide report?
Analytics
Analytics — 12 questions
- What is RP-HPLC and why is it used for peptides?
- Why are peptides measured at 214 nm?
- What is retention time co-elution?
- What is the TFA salt issue in peptides?
- What is the difference between acetate and arginate salt forms?
- What are endotoxins in peptides?
- Do peptide testing labs test for sterility?
- When do I need LC-MS for a peptide?
- What is a reference standard in peptide testing?
- What is a limit of quantification?
- What is carryover in chromatography?
- What is duplicate quantification?
Buying
Buying — 12 questions
- How do I blind-test a vendor?
- Why did my peptide fail its label claim?
- How many mg should be in my peptide vial?
- Is underfilling common in research peptides?
- Can I trust a vendor's own certificate of analysis?
- Can I trust a lab that publishes results selectively?
- What is cherry-picking in peptide testing?
- Should vendors pay for their own testing?
- What does third-party tested actually mean?
- How often should a vendor test their products?
- What is batch or lot testing?
- Does a QR code on a vial prove anything?
Logistics
Logistics — 12 questions
- How do I send peptides to a laboratory for testing?
- How much sample does a laboratory need for peptide testing?
- Do I need to ship peptides cold for testing?
- Can I ship peptides internationally for testing?
- What happens if my vial breaks in transit?
- How long does peptide testing take?
- How much does peptide testing cost?
- Can I test an already-reconstituted peptide?
- Can I test a peptide blend?
- Can a capsule or oral peptide product be tested?
- Do laboratories test unlabelled or anonymous samples?
- What if my peptide is not on the price list?
Laboratories
Laboratories — 12 questions
- Is Janoshik legit?
- How long does Janoshik take?
- What does Janoshik charge for peptide testing?
- What are the alternatives to Janoshik?
- Which peptide testing labs have ISO 17025 accreditation?
- Does a laboratory need ISO 17025 to be trustworthy?
- Are there peptide testing labs in Europe?
- Are there peptide testing labs in the United States?
- Why do peptide testing prices vary so much?
- Can I use a university laboratory to test peptides?
- What makes a testing laboratory independent?
- What is a blind GLP-1 panel?
Iberian Analytical opens in Q1 2027 — €99 per test, 48–72 h target, and every result published in a public database, mandatory and free. Nothing is sold on this site today. Leave an email and we will write once, when the laboratory starts issuing certificates.