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Peptide science, written by the lab that tests them.
Independent reference articles on how peptides are made, purified, characterized, and verified. We focus on chemistry and analytical method — we do not publish dosing, prescribing, or clinical guidance.
- Manufacturing · 11 min
Peptide synthesis: how SPPS actually works
Solid-phase peptide synthesis from resin loading through global deprotection — and why every coupling cycle is a chance to introduce impurities.
Read article - Purification · 9 min
Peptide purification by reverse-phase HPLC
How crude peptide is separated from deletion sequences, truncations, and oxidized analogs using preparative RP-HPLC, gradient design, and counter-ion exchange.
Read article - Analytical · 12 min
Characterizing a peptide: HPLC, LC-MS, AAA, NMR
The four assays that together establish identity, purity, content, and structure — what each one measures, what it cannot, and how they corroborate.
Read article - Failure modes · 10 min
Common peptide impurities and where they come from
Deletion sequences, truncations, racemization, oxidation, deamidation, dimerization, and residual TFA — what causes each, how it shows up on chromatograms, and what it means for end use.
Read article - Stability · 8 min
Peptide stability and storage: a practical primer
Lyophilized vs. reconstituted stability, cold-chain reality, freeze-thaw, light and oxygen sensitivity, and how stability is actually measured in a regulated lab.
Read article - Verification · 9 min
How to read a peptide Certificate of Analysis
Walk through every section of a peptide COA — identity, purity, content, residual solvents, endotoxin, counter-ion — and learn which numbers actually matter.
Read article - Verification · 6 min
What is a peptide COA?
The Certificate of Analysis behind every serious peptide order: what it is, the four numbers it must show, who should issue it, and how to verify one before you buy.
Read article - Verification · 7 min
Peptide COA questions, answered
The questions buyers actually ask about peptide Certificates of Analysis: what to check first, what purity really means, vendor vs third-party COAs, fake documents, and how to verify a batch.
Read article - Verification · 7 min
How to buy peptides with a COA you can actually trust
The buyer's checklist before ordering: what to demand from a seller, how to read the COA in five minutes, the red flags that end the order, and when to test the vial yourself.
Read article - Verification · 8 min
Where to buy peptides online: how to choose a source you can verify
The verification-first buyer's guide: the main sourcing channels compared, the five-minute pre-order COA checklist, what price does and doesn't tell you, and when to test the vial yourself.
Read article - Verification · 8 min
The peptide buyer's FAQ
Twelve questions, three themes: how to choose a peptide and a seller, what to check on a COA before you pay, and how to read the identity, purity, and content numbers.
Read article - Verification · 7 min
Peptide buyer journey: from finding a seller to checking the vial
A six-step map from where to buy peptides online through the COA checklist, independent verification, ordering, and matching the delivered vial to its report.
Read article - For brands · 8 min
Shipping peptide samples for testing: best practices that protect your results
How to ship peptide samples to a testing lab without degrading them: stable form, cold chain, packaging, sealing, lot labeling, documentation, and what to do if a result comes back failed.
Read article - Verification · 7 min
Why third-party peptide testing matters
Why an independent lab — one that does not manufacture or sell the peptide — is the only credible source of identity, purity, and content data for a research peptide batch.
Read article - Buyer's guide · 8 min
How to spot a trustworthy peptide supplier
A buyer-side checklist for evaluating peptide vendors: transparency of methods, batch-level traceability, independent verification, and the small details that separate a credible supplier from a confident-looking one.
Read article - Verification · 7 min
How to tell if your peptide is actually third-party tested
Third-party tested is one of the most overloaded phrases in the research peptide market. The buyer-side diagnostic: what the claim has to mean, what proof has to look like, and how to spot a marketing claim dressed up as one.
Read article - Analytical · 11 min
Peptides and drug tests: how anti-doping labs detect them
How accredited anti-doping and clinical laboratories actually detect peptide hormones — sample preparation, LC-HRMS panels, WADA-style screening and confirmation, and the analytical limits of each method.
Read article - Analytical · 5 min
Does Tirzepatide show up on a drug test?
A laboratory-grounded answer to whether Tirzepatide (a 39-residue GIP/GLP-1 dual agonist, 4814 Da) appears on standard 5- and 10-panel urine drug screens, and where it can be detected by dedicated LC-HRMS methods.
Read article - Verification · 8 min
What are certified peptides? Independent verification vs. vendor COAs
A working definition of “certified peptides” grounded in analytical chemistry: independent, ISO 17025-accredited testing published as a batch-specific, tamper-evident record — and why a vendor-issued PDF is not the same thing.
Read article - Thought leadership · 16 min
Peptide testing transparency: how CertikLabs is rewriting the rules Janoshik wrote
A deep dive on the structural gaps in the legacy independent-peptide-testing model — distribution, tamper-evidence, traceability, and analytical literacy — and how CertikLabs is closing all four at once with public verification URLs, on-chain anchoring, vial-to-report QR, and an open educational library.
Read article - Analytical · 12 min
Endotoxin testing for peptides: what LAL detects that HPLC cannot
Endotoxins are bacterial membrane fragments that survive sterilization, slip past HPLC purity, and quietly explain a meaningful slice of "99% pure" peptides that still cause fever. A chemistry-grounded guide to LAL and recombinant Factor C testing, EU thresholds, and how to read a credible endotoxin result.
Read article - Verification · 9 min
Peptide blind testing: how to verify a lab is not fabricating results
Blind testing is the only buyer-side experiment that proves an independent peptide lab actually runs the assays it reports. Single-blind, split-sample, and substituted-blind protocols — plus what a credible result looks like and the common failure patterns of a marketing lab.
Read article - Verification · 10 min
GLP-1 peptide blind testing: verifying semaglutide, tirzepatide, and retatrutide
GLP-1-specific blind-testing protocol for semaglutide, tirzepatide, and retatrutide — what to send, what an LC-HRMS + peptide-mapping report should show, expected costs, and how to interpret purity and content against the labeled molecular weight.
Read article - Methodology · 11 min
HGH testing methodology: HCP ELISA, SEC-HPLC, and peptide mapping for recombinant somatropin
Why recombinant HGH (191 aa somatropin) needs more than RP-HPLC — the specific role of size-exclusion HPLC for dimers/aggregates, host-cell protein ELISA, tryptic peptide mapping, intact-mass LC-HRMS, and bacterial endotoxin in a defensible independent verification.
Read article - Buyer's guide · 11 min
HGH peptide testing: a buyer's guide to verifying somatropin before you use it
A buyer-facing guide to HGH peptide testing — how substituted secretagogues, aggregation, host-cell protein, and endotoxin show up in practice, which assay tier each buyer needs, how mail-in submission works when no analytical lab is nearby, what it costs, and how to read the report.
Read article - Buyer's guide · 11 min
GLP-1 peptide testing: a buyer's guide to verifying semaglutide and tirzepatide
A buyer-facing guide to GLP-1 peptide testing — missing fatty-diacid side chains, analog substitution, synthesis impurities, content and endotoxin, which assay tier each buyer needs, how mail-in submission works when no analytical lab is nearby, what it costs, and how to read the report.
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Editorial stance
What you will and will not find here
CertikLabs Learn covers peptide chemistry, manufacturing, analytical methods, and verification. Where a peptide's mechanism of action is well-established in the published literature, we summarize it factually with citations.
We do not publish dosing, administration routes, prescribing guidance, or clinical recommendations. Peptides discussed here are research and pharmaceutical reference compounds. Anything intended for human use must be obtained, prescribed, and administered by a qualified, licensed clinician.