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c/compounding·posted 4 days ago by u/ffmi_watcher

asked my compounder where the API comes from. long silence.

Regulatory Well Actually ×8

asked my compounder where the API comes from. long silence. Not a hot take, just something I have not seen said plainly here.

Compounded preparations are not approved products and carry no bioequivalence claim. That is a statement about regulatory category, not about quality.

Why "compounded" is not "generic", written out because the confusion is constant.

A generic is an approved product demonstrated to be bioequivalent to a reference. A compounded preparation is made for a patient or, in the case of an outsourcing facility, under a different regulatory route entirely. It carries no equivalence claim and it is not required to demonstrate one.

That is not a quality judgement. Plenty of compounded preparations are made carefully in facilities with real testing programmes. It is a statement about what has and has not been established, and the difference matters when people assume the two are interchangeable.

On concentration, which is where I see people actually get hurt.

A compounded vial can be filled at a different concentration from the branded product you were previously using. If you carry over your old arithmetic — same number of units, different mg/mL — you draw a different amount and may not notice for weeks.

Read the label every time you switch. Redo the arithmetic on paper. Write the concentration on the vial. It is the same habit c/reconstitution keeps preaching and this is the case where it actually bites.

Research-use-only material is not approved for human use and nothing here should be read as a recommendation to use it.

546 up / 52 down91% upvoted27 commentsid 1m6u2326 Jul 2026

27 comments

19 in this archive, depth 5

best — the order this archive was captured in

u/swirl_dont_shakereconstitution35 points·3 days ago·edited

A 503A pharmacy compounds for an identified patient against a prescription. A 503B outsourcing facility registers with the regulator, may produce without patient-specific prescriptions, and is subject to current good manufacturing practice requirements. The two are governed differently and the difference is not cosmetic.

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u/ffmi_watcherOP-9 points·3 days ago

a telehealth intake that asks nothing has told you what it is

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u/ffmi_watcherOP1 point·3 days ago

Small fix — 503B facilities register with the regulator; 503A pharmacies are licensed by the state board. Different mechanisms.

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u/clara_danquah20 points·3 days ago

The intake asked me three questions and none of them were about my history. That told me everything I needed to know about the model.

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u/blunt_coldbox_notes16 points·2 days ago

Push back: "compounded is fine because a pharmacy made it" skips every question this board exists to ask.

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u/discount_math_dm28 points·3 days ago

Switched between two compounded preparations and the concentration on the label was different. Redid the arithmetic on paper before drawing anything.

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u/teodor_duarte9 points·3 days ago

503A is patient-specific, 503B is outsourcing facility, they are not the same thing

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u/receptor_bias_rick17 points·3 days ago

Not convinced. You are comparing a compounded concentration with a branded one and assuming they match.

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u/rania_diallo4 points·2 days ago

A beyond-use date derived from published stability data means something different from one assigned by default rule. Asking which is a fair question and the answer is usually available.

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u/usp_appendixMOD10 points·2 days ago

Left up. It describes an arrangement with specifics and it is honest about the jurisdiction.

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u/gustav_cardoso12 points·2 days ago

do not assume the concentration matches the branded product

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u/tobias_vukovic14 points·2 days ago

Paid noticeably more at one clinic than another for what turned out to be the same facility behind both.

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u/milos_mensa8 points·2 days ago

the pharmacy and the prescriber are two separate questions

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u/ffmi_watcher3 points·2 days ago

Yes. The shortage list is the legal hinge for the whole arrangement and its status is public.

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u/dario_stanescu7 points·2 days ago

Asked which facility and got a name straight away. Looked it up, found the registration, felt considerably better about the whole thing.

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u/ahmed_fonseca2 points·1 days ago

a 503B has to register and report, so there is a paper trail to ask for

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u/amara_kuipers2 points·1 days ago

Salt form matters for mass: a preparation specified as one salt and dosed as the free base gives you a different amount of peptide for the same number on the label.

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u/sofia_nascimento2 points·1 days ago

Asked for potency testing on the finished preparation. They had it. I had assumed they would not.

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u/ffmi_watcherOP1 point·1 days ago

That figure is the starting material purity, not the finished preparation potency. Two different tests.

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About c/compounding

Compounded GLP-1s as a supply route: the 503A/503B distinction, the shortage-list mechanics that made compounding legal and then didn't, state board rules, telehealth prescriber models, and what a compounding pharmacy will and will not tell you about its API source.

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