DataDave said:They are two different exemptions from the same federal requirements and they buy different things.
I read this differently from DataDave, on substance rather than tone. 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.
CryptoCarl 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…
Compounding pharmacy red flag checklist for compounded supply — if ANY of these apply, find a different source:
- No verifiable physical address
- No pharmacist available for consultation
- COA not available or clearly template/fake
- Prices dramatically below market ($30-40/month = suspicious)
- No prescription required
- Ships without cold pack or temperature control
- No batch/lot numbers on product labeling
- Pushes "research use only" products for human injection
Your health depends on product quality. Don't cut corners on source verification.
PharmacoVig_BOS said:A research-chemical supplier selling lyophilised powder labelled research use only is not compounding and is not claiming to.
Compounding pharmacy licensing verification for compounded supply: before ordering, verify your pharmacy's credentials:
- State Board of Pharmacy license — check on your state BOP website
- FDA registration (for 503B) — check on fda.gov
- DEA registration if handling controlled substances
- PCAB accreditation — voluntary but demonstrates commitment to quality
- USP <797>/<800> compliance for sterile compounding
This takes 10 minutes of research and could save you from receiving substandard or unsafe medication.
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View ResultsA narrower follow-up, since the general answer is now clear:
What actually distinguishes 503A from 503B, in terms of what each may make and from what starting material?
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.