pete_nash said:

The provenance questions are more useful than the numbers.

pete_nash has the substance of this right. The condition it depends on is worth stating. One addition: an unstated method makes a report close to uninterpretable. "99% pure" without the technique, the standard and the conditions is a claim, not a measurement.

wei_SG said:

Agreed, with a caveat about community reputation: it is a lagging indicator.

Thank you for spelling out the reasoning rather than just the conclusion. I will report back once I have actually tried it.

pete_nash said:

The provenance questions are more useful than the numbers.

I am more sceptical of certificates as a category than this thread is. The document tells you about a sample somebody chose to send, at a moment in time, and nothing about the vial in your hand. Independent purchase-and-test is a different quality of evidence and everything else is inference.

FranDenver said:

Six orders from the same supplier over eight months, every one independently tested, and the consistency is the part worth reporting rather than any…

Shipping damage protocol for vendor vetting orders: if your package arrives with visible damage, temperature excursion, or broken vials:

• Photograph EVERYTHING before discarding packaging
• Note the temperature of the cold pack (liquid = possibly too warm)
• Contact the vendor within 24 hours with photos
• Request a replacement shipment or refund
• Do NOT use potentially compromised medication

Reputable vendors will replace damaged shipments without argument. If they push back, that's a red flag about the vendor.

Moderator note: the sourcing question belongs in the vendor section and has been split out. Thread quality here is what the rules are for. Keep it up.