Dr.NutriCornell said:

503A vs 503B compounding pharmacies for compounded supply — this distinction matters enormously: Feature 503A 503B Regulation State Board of Pharmacy…

Vendor communication red flags for compounded supply:

• Won't provide COA before purchase — walk away
• Claims "100% pure" without analytical data — unrealistic
• No physical address or phone number — accountability matters
• Pushes you to buy more than you need — pressure tactics
• Won't answer questions about their compounding process — transparency is key
• Payment only via crypto or wire transfer — legitimate pharmacies accept cards

A legitimate compounding pharmacy operates like a healthcare business, not a gray market dealer.

TrialTracker_MD said:

Agreed, and the enforcement dates were staggered by category — 503A first, 503B a few weeks later — because outsourcing facilities have manufactured…

This answered a question I did not know how to ask. I will report back once I have actually tried it.

Dr.NutriCornell said:

503A vs 503B compounding pharmacies for compounded supply — this distinction matters enormously: Feature 503A 503B Regulation State Board of Pharmacy…

Regarding compounded supply compounding legality: compounding pharmacies can legally produce semaglutide and tirzepatide while these drugs remain on the FDA shortage list. If/when the shortage resolves, the legal landscape may change.

Stay informed. The FDA shortage list is updated regularly. Current status as of my last check: semaglutide partially resolved shortage, tirzepatide still in shortage. This directly impacts compounding availability.

CarlaRPh_TPA 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…

Price comparison for compounded supply across sources I've used:

I use the 503B option — best balance of quality, cost, and legality. The brand price is insane but insurance can help if you qualify.

Moderator note: the sourcing question belongs in the vendor section and has been split out.