GLP-1 Basics
What is a compounding pharmacy?
A compounding pharmacy custom-makes medications rather than dispensing pre-manufactured ones. They became central to the GLP-1 market when semaglutide went on the FDA shortage list in 2022 — and understanding how they work matters if you're considering a compounded program.
The basic idea
Most pharmacies dispense drugs. A manufacturer makes a pill or vial, ships it to a distributor, and a pharmacy hands it to you exactly as it was made. The drug is standardized — same dose, same inactive ingredients, same delivery format for everyone.
Compounding pharmacies work differently. They start with raw pharmaceutical ingredients and make the drug themselves, to a specific formulation. That might mean a different dose than what's commercially available, a different delivery format (liquid instead of pill, for example), or the removal of an ingredient a patient is allergic to.
Compounding has existed as long as pharmacy has. Before mass drug manufacturing, nearly all medications were compounded. The practice narrowed through the 20th century as standardized manufacturing became the norm, but it never disappeared — and for specific clinical situations, it's the only option that works.
Why compounding pharmacies exist
There are four main situations where a commercial drug doesn't work and a compounded version does:
- The dose doesn't exist commercially
- A child needs a pediatric dose of a drug only made for adults. An elderly patient needs a lower concentration than the manufacturer offers. Compounders can make the exact dose a physician prescribes.
- The patient can't tolerate an inactive ingredient
- Commercial drugs contain fillers, dyes, preservatives, and coatings. A patient with a severe allergy to one of these can't use the commercial version. A compounding pharmacy can make the same active ingredient without the offending additive.
- The drug is on shortage
- When the FDA declares an official drug shortage, compounding pharmacies can legally produce copies of that drug. This is what opened the door for compounded semaglutide in 2022 — the GLP-1 market grew faster than Novo Nordisk's manufacturing capacity, the FDA declared a shortage, and compounders stepped in.
- The drug was discontinued
- A manufacturer stops producing a drug because it isn't profitable enough. If physicians still need it, compounders can keep making it.
503A vs. 503B: the two types
Federal law created two categories of compounding pharmacy, and the distinction matters when evaluating a GLP-1 program.
503A — Traditional Compounder
- Fills prescriptions for individual patients
- Requires a valid prescription before dispensing
- Regulated by your state pharmacy board
- Cannot sell to other states without a license in that state
- The most common type — most local compounders are 503A
503B — Outsourcing Facility
- FDA-registered and inspected
- Can produce larger batches without individual prescriptions
- Sells to hospitals, clinics, and telehealth providers
- Subject to Current Good Manufacturing Practice (CGMP) standards
- More rigorous quality controls — closer to a small drug manufacturer
For GLP-1 programs, the major telehealth providers partner with either 503A or 503B pharmacies — sometimes both. You can verify 503B status on the FDA's public outsourcing facility registry. For 503A, check your state pharmacy board's license lookup. Both take about two minutes.
How they're regulated
Compounded medications are not FDA-approved. That phrase sounds alarming but needs context. FDA approval applies to a specific finished drug product from a specific manufacturer — it means that product went through clinical trials and met the FDA's manufacturing standards. A compounded drug skips that process by definition, because it's custom-made rather than mass-produced.
What compounders are regulated on: the active pharmaceutical ingredients (APIs) they use must come from FDA-registered suppliers. The pharmacies themselves must be licensed by their state pharmacy boards (503A) or registered with the FDA (503B). And they must follow USP standards — specifically USP 795 for non-sterile preparations and USP 797 for sterile preparations like injectable semaglutide. These standards govern everything from clean room requirements to testing and labeling.
The gap between a licensed 503B facility and a grey market peptide vendor is not theoretical. Independent testing of grey market products — unregulated vendors selling compounds "for research use only" without a prescription — has found impurity rates as high as 86% and quantity variances of 50% or more. Licensed compounders are tested, inspected, and liable. Grey market vendors are none of these things.
What to look for when evaluating a compounding pharmacy
If a telehealth provider is sending your medication from a compounding pharmacy, you can and should know which one. Most reputable providers will tell you. Here's what to verify:
Five things to check
State pharmacy board license or FDA outsourcing facility registration — both are public records.
Certificates of Analysis (COAs) available on request — these are third-party lab reports confirming potency and purity of each batch.
USP 797 compliance for injectable medications — sterile compounding has strict clean room and testing requirements.
PCAB accreditation (Pharmacy Compounding Accreditation Board) — not required, but a meaningful quality signal.
The pharmacy name itself — not just "a licensed compounding pharmacy." Get the actual name and verify it yourself.
Compounding pharmacies and GLP-1s: where things stand
From 2022 through early 2025, compounded semaglutide was legal under the FDA shortage exemption. Thousands of 503A and 503B pharmacies produced it, telehealth providers built businesses around it, and patients accessed it at $150–300/month versus $1,300+ for the branded version.
The FDA officially resolved the semaglutide shortage in February 2025. That changed the rules: pharmacies can no longer compound drugs that are "essentially a copy" of a commercially available, in-stock product. Compounded formulations with meaningful modifications — primarily the addition of B vitamins, which have documented clinical use in managing GLP-1-related nausea — remain available through licensed providers.
The tirzepatide shortage status is still contested in court. Multiple compounders filed suit against the FDA over the shortage resolution timeline. As of April 2026, compounded tirzepatide with modifications remains available through some providers while litigation continues.
If you're evaluating a GLP-1 program, the question to ask is not "compounded or branded" — it's whether the provider uses a licensed pharmacy, requires a physician prescription, and can tell you exactly where your medication is made. Those answers matter regardless of which route you take.
