claudia_zurich said:

They are not contradictory, they measure different things, and this is the single most common misreading of a certificate.

That reframing is the part I needed.

Adding the clinical framing, because it changes how the question reads.

Reconstituted peptide stability data for certificates of analysis: I had Janoshik test my reconstituted vial at day 1, day 14, and day 28 stored in the refrigerator.

Day 1: 100.1% purity
Day 14: 99.1% purity
Day 28: 99.5% purity

Minimal degradation over 28 days when properly refrigerated. This confirms the standard 28-day beyond-use date is appropriate. Beyond 28 days, I'd reconstitute a fresh vial to be safe.

Dr.RaviCardio said:

I tested my certificates of analysis batch through Janoshik — 98.4% purity.

Third-party testing services for certificates of analysis besides Janoshik:

• Janoshik: Gold standard for peptide community, ~$126, 10-14 day turnaround
• Valitech: US-based, ISO 17025 accredited, ~$206
• Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
• ChemTox: Basic identity and purity testing, ~$116

Janoshik is the community standard but any ISO-accredited analytical lab can verify peptide identity and purity. The key is independence — don't rely solely on the vendor's own testing.

RunnerRach said:

The provenance questions are more useful than the numbers.

COA red flags for certificates of analysis — here's what to look for when reviewing a Certificate of Analysis:

• No HPLC data: If there's no chromatography graph, it's not a real COA
• Exact 100% purity: Suspicious — real testing always shows slight variation
• No batch number: Can't trace back to specific production
• No endotoxin testing: For injectables, this is essential
• Template looks like it was made in Word: Professional labs have standardized formats

I have seen fake COAs that are literally photoshopped. Always verify independently if possible.

Moderator note: a couple of off-topic posts removed.