# ACS Peptide Testing Under ASTM D8558 and the Upcoming ASTM F49 Standard
At ACS Laboratory, every peptide sample we accept moves through a documented, standards-driven workflow. Two ASTM references anchor that workflow: ASTM D8558, which we operate under today for peptide identity, purity, and impurity testing, and the emerging ASTM F49 family of standards for medical and research peptides that our scientific team is actively helping to shape.
This post walks through what those standards mean, why they matter for compounding pharmacies, research labs, and peptide manufacturers, and how ACS's ISO/IEC 17025:2017 accredited methods align with both.
Why standards matter for peptides
Peptide products sit in a regulatory gray zone. Many are sold for research use only, others are compounded under 503A/503B rules, and the analytical expectations vary widely between vendors. Without a shared standard, "99% pure" from one lab does not mean the same thing as "99% pure" from another, different columns, different gradients, different reference materials, and very different reporting practices.
ASTM International's consensus standards close that gap. They define:
- Which analytical techniques are acceptable
- How reference materials must be qualified
- How impurities are identified, quantified, and reported
- What a Certificate of Analysis (COA) must disclose
When a lab operates under an ASTM method, its results become comparable across facilities, across states, and across regulatory audits.
ASTM D8558, the current standard ACS operates under
ACS Laboratory runs its peptide identity, purity, and related-substance panels in alignment with ASTM D8558, the current consensus standard for chromatographic characterization of synthetic peptides.
Under D8558, our testing includes:
- Identity confirmation by high-resolution LC-MS with monoisotopic mass matching within tight ppm tolerances
- Purity determination by reversed-phase HPLC with UV detection at 214 nm, integrated across the full elution window (not just the main peak)
- Related substance profiling including deletion sequences, oxidation products, dimers, and truncations reported as individual and total impurities
- Net peptide content by nitrogen or amino acid analysis for dosage-critical peptides such as tirzepatide, semaglutide, retatrutide, and sermorelin
- Documented reference standards with certificates and traceability
Every COA we issue under D8558 cites the method, the column chemistry, the gradient, and the calibration approach. That is what turns a number on a page into defensible data.
ASTM F49, the new standard on the horizon
ASTM Committee F49 is the newest ASTM technical committee focused specifically on peptide therapeutics, research peptides, and the analytical and manufacturing standards that support them. The committee is currently drafting a family of standards that will expand well beyond D8558 to cover:
- Peptide manufacturing quality systems for compounding pharmacies and 503B outsourcing facilities
- Stability and forced-degradation study design
- Endotoxin, bioburden, and sterility expectations for injectable peptide products
- Reconstitution, storage, and handling standards
- Reference material qualification programs specific to GLP-1s, growth hormone secretagogues, and healing peptides
ACS's scientific team is participating in the F49 workstream because we see the same quality gaps our clients see: inconsistent COAs, unqualified in-house testing, and reference materials of unknown provenance. F49 is designed to fix that at the industry level.
