A narrower follow-up, since the general answer is now clear:

How would you tell the difference between that and the alternative explanation?

Dr.Martinez said:

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

Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members. Across 61 submitted tests:

• 78% tested at ≥98% purity
• 15% 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.Martinez said:

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

Agreed, with the usual condition: that holds for the average and this board is a collection of individuals. A population claim and a personal prediction are different things and get quoted interchangeably.

Dr.Martinez said:

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

Thank you — that is the clearest version of this I have read, and I have read a lot of them.

Adding the clinical framing, because it changes how the question reads. The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either. Those three things can all be true at once, and most arguments here are two people holding different parts of that.

Correct me if the detail matters more than I have assumed.