Clinical perspective, offered as context rather than as advice.

My vendor review relevant to certificates of analysis: ordered 5 times from my current compounder. Consistency has been excellent.

Shipping: Same-day local pickup
Packaging: Professional, discreet, proper labeling with lot/batch numbers
Purity: 97.2% average across orders (Janoshik verified)
Customer service: Responsive within 6 hours
Price: $146/month for semaglutide 2.4mg equivalent

BiostatsBrad said:

I tested my certificates of analysis batch through Janoshik — 97.3% purity.

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

• Janoshik: Gold standard for peptide community, ~$127, 10-14 day turnaround
• Valitech: US-based, ISO 17025 accredited, ~$227
• Eurofins: Full pharmaceutical testing suite, more expensive but comprehensive
• ChemTox: Basic identity and purity testing, ~$107

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.

BiostatsBrad said:

I tested my certificates of analysis batch through Janoshik — 97.3% purity.

Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members. Across 62 submitted tests:

• 82% tested at ≥98% purity
• 12% tested at 95-98% purity
• 6% tested at <95% purity (concerning)

The vendors with consistently high purity results are listed in the Vendor Directory. We update monthly based on new community submissions.

One thing that is still open after BiostatsBrad’s answer:

What did you change at the same time, and can you separate the two now?

Moderator note: a post naming a supplier has been edited. Discuss suppliers in the review sections, not here. Thread quality here is what the rules are for. Keep it up.