Dr.AddMedPHL said:

My HPLC chromatogram analysis for certificates of analysis — I sent my batch to Janoshik and here's what the results showed: Main peak retention time:…

Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members. Across 51 submitted tests:

• 75% tested at ≥98% purity
• 18% tested at 95-98% purity
• 7% 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.

Dr.AddMedPHL said:

My HPLC chromatogram analysis for certificates of analysis — I sent my batch to Janoshik and here's what the results showed: Main peak retention time:…

Thank you for spelling out the reasoning rather than just the conclusion. Sending this to two other people who asked me the same thing last week.

Clinical perspective, offered as context rather than as advice. Take it one variable at a time. Almost every unanswerable question in these threads is unanswerable because three things changed in the same fortnight, and no amount of subsequent argument can untangle them after the fact.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

Dr.CardioMD said:

Almost every unanswerable question in these threads is unanswerable because three things changed in the same fortnight, and no amount of subsequent…

Same experience, arrived at from the opposite direction.

Dr.CardioMD said:

Almost every unanswerable question in these threads is unanswerable because three things changed in the same fortnight, and no amount of subsequent…

Adding the part of the answer the thread has not reached. Whatever the answer turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, and invite the correction. That is slower than asserting, and it is the only version that survives being wrong.