August 2026 FDA Warning Letters to Peptide Sellers: How “Research Use Only” Is Being Read
Four warning letters dated August 24, 2026 spell out when FDA treats a research-use-only peptide as an unapproved drug. The label is not the test.
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tesamorelin
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Tesamorelin: What the Clinical and Preclinical Literature Shows
Tesamorelin is a stabilized GHRH analogue and the active ingredient of Egrifta. Its phase 3 trials, liver and cognition studies, and evidence limits.
What Is HPLC and How Does It Measure Peptide Purity?
HPLC separates a peptide from its impurities on a column and reports the result as a chromatogram. Here is how it works and how to read one on a COA.
Why Third-Party Lab Testing Matters for Research Peptides
A supplier grading its own product is a conflict of interest, not a quality system. What independent testing adds, what it cannot fix, how to read it.
Mass Spectrometry: How a Peptide’s Identity Is Confirmed
Purity tells you how much of a sample is one thing. Mass spectrometry tells you what that thing is. Here is how the identity check works.
GH vs. GHRH vs. GHRP: Untangling the Growth-Hormone Axis
Three classes of molecule act at three points in the growth-hormone axis. What each is, which receptor it binds, and why the distinction matters.
Net Peptide Content vs. Purity: Two Numbers, Two Different Questions
A vial can be 99% pure and 75% peptide by weight at the same time. Counter-ions, bound water and how amino-acid analysis resolves the difference.
Endotoxin Testing in Peptide Quality Control
Endotoxin is the contaminant that survives sterilization. How LAL and recombinant assays detect it, and what an endotoxin result on a COA means.
All content in the research library is educational and intended for qualified researchers. Products referenced are for laboratory research use only and are not approved for human or veterinary use. Nothing here is medical advice.