Dr.SurgeonPGH said:

The shortage clause is the answer to the second question and it is a subtraction rather than an addition.

Pushing back on Dr.SurgeonPGH here. A research-chemical supplier selling lyophilised powder labelled research use only is not compounding and is not claiming to. It is a different legal universe with no pharmacy oversight, no patient relationship and no content guarantee, and conflating the two in these threads helps nobody.

robert_kc said:

Two pharmacies quoted me last year, one describing itself as 503A and one as 503B, and I assumed 503B just meant bigger until both stopped within…

For compounded supply users considering compounded for the first time: here's a step-by-step guide:

1. Get a prescription from your doctor (telehealth counts)
2. Research 503B compounding pharmacies with good community reviews
3. Verify their FDA registration and inspection history
4. Request a COA for your specific compound before ordering
5. Start with a 1-month supply to test
6. Consider sending a sample to Janoshik for independent verification
7. Track your response compared to brand (if you were on it previously)

Dr.PainCLE said:

A research-chemical supplier selling lyophilised powder labelled research use only is not compounding and is not claiming to.

There is a second half to this that has not been said yet. The trade-off is reversibility against privacy and there is no option that gives you both. Card payments are reversible and disclose the most; crypto discloses least and is irreversible, which is precisely why pressure toward it is a warning sign when it comes from a seller rather than a buyer. Escrow only means anything where the escrow agent is independent of both parties, which is rarely the case in practice.

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

Why a shortage listing created a legal pathway at all, since a shortage is a supply fact rather than a permission?

OP back with an update, since a thread like this is useless without one.

The bulks-list asymmetry was the piece I had missed entirely. It explains why one of my two pharmacies is still arguing it can supply and the other simply stopped.