FDA Category 1 vs. Category 2 Peptides: What the Difference Actually Means for Your Clinic

A Label That Gets Treated Like a Simple Answer

"Category 1" and "Category 2" show up constantly in peptide sourcing conversations, and the confusion runs in both directions. Some vendors treat "Category 1" as a full legal green light, which overstates it. Others assume neither category means anything until a substance reaches the final Bulks List, which understates it — Category 1 actually does carry a real, current compounding basis under FDA's own interim policy, just not a permanent one. Understanding precisely what each category does and doesn't authorize is the difference between a sourcing decision your medical director can defend and one that just sounds defensible.

Where the Categories Come From

Under section 503A, a bulk drug substance is only lawful for a compounding pharmacy to use if it clears one of three specific paths: it has an applicable USP or National Formulary monograph, it is a component of an already FDA-approved drug, or it appears on the final 503A Bulks List codified at 21 C.F.R. § 216.23. That final list is short, and getting a new substance added to it requires FDA to publish a proposed rule, take public comment, and issue a final rule.

Before a substance can even be considered for that list, someone has to nominate it, and FDA's Pharmacy Compounding Advisory Committee reviews nominated substances on an ongoing basis. Category 1 and Category 2 are the risk tiers FDA assigns to a substance during that review — a status update on an unfinished process, not the outcome of it.

Category 1 vs. Category 2, Plainly

• Category 1: FDA has not identified a significant safety risk for the substance based on the information reviewed so far, and under FDA's interim compounding policy, a Category 1 substance may currently be used by a 503A pharmacy to compound a patient-specific prescription while formal review continues. That is real, present-tense compounding permission — it just runs on an enforcement-discretion basis rather than the permanent legal footing a final Bulks List listing carries, and it can be withdrawn if new safety information moves the substance to Category 2.
• Category 2: FDA has identified a significant safety risk for the substance. FDA generally recommends compounding pharmacies not use a Category 2 substance at all while that risk is under evaluation, because the concern is considered to outweigh the unclear benefit during the review period.
• Neither category: is the final 503A Bulks List. A substance can move between these tiers, get removed from active tracking entirely, or eventually reach the final list — and only the final list gives a substance permanent, unconditional legal standing for 503A compounding, independent of FDA's discretion.

Why This Distinction Actually Matters for Sourcing

A vendor or a patient citing "it's Category 1, so it's safe" is overstating what the category means — it's a provisional, review-stage classification, not a safety conclusion, and it can move to Category 2 if new information surfaces. But it would be just as much of a mistake to swing the other way and assume Category 1 means nothing legally. Under FDA's interim compounding policy, Category 1 status is exactly what currently lets a 503A pharmacy compound that substance at all, on an enforcement-discretion basis, while the formal review plays out. GHK-Cu, added to Category 1 in May 2026, is a real example of a peptide a licensed compounding pharmacy can lawfully work with today on that basis.

This is also why reclassifications are worth watching closely rather than treated as background noise. When FDA moves a substance out of active Category 2 tracking without placing it in Category 1 — as it did with a group of peptides including BPC-157 and TB-500 in April 2026 — that's a bookkeeping change to how the substance is tracked, not a new compounding basis and not a step toward one. It does not place the substance on the final list, and it does not authorize compounding, which is a meaningfully different outcome than a substance actually landing in Category 1.

Where the Recently Reviewed Peptides Currently Sit

The peptide families that got attention from FDA's advisory committee in 2026 — BPC-157, KPV, TB-500, MOTS-c, Epitalon and Semax, all of which received favorable committee recommendations — started this process as nominated substances working through exactly this kind of risk-tier evaluation. A favorable advisory vote is a meaningful step in that process, but as of that vote, none of them had reached the final Bulks List, and none were newly legal to compound on that basis. See our full breakdown of what the vote actually changed for the complete picture, including how individual states have taken their own, sometimes stricter, enforcement positions on these same substances.

Where MedGrid Fits

When a provider prescribes a peptide inside the MedGrid platform, the order routes to a partner pharmacy checked against what it's actually permitted to compound today — not against a vendor's marketing claim about which risk category a substance sits in. Your medical director reviews peptide protocols on the same cadence as the rest of your service menu, so a reclassification gets caught and addressed rather than discovered later.

Frequently Asked Questions

• Does Category 1 mean a peptide is legal to compound?: It means a 503A pharmacy currently may compound it, under FDA's active enforcement-discretion policy while formal review continues — a real, present basis, but a provisional one, not the same as the permanent legal standing a final 503A Bulks List listing carries.
• Does Category 2 mean a peptide is banned?: Not in a formal legal sense — it means FDA has identified a significant safety risk and generally recommends against compounding pharmacies using it at all while that risk is under review. In practice, that recommendation is why a Category 2 substance is not one a licensed compounding pharmacy would use.
• If a substance moves out of Category 2, is it now approved for compounding?: Only if it lands in Category 1 or reaches the final Bulks List. Moving out of active Category 2 tracking without landing in Category 1 — which is what happened to a group of peptides including BPC-157 in April 2026 — is a bookkeeping change to how FDA is tracking the substance, not a new compounding basis.
• How should my clinic actually use this information?: As one input your medical director weighs alongside the substance's actual legal status, your state's enforcement posture, and your pharmacy's own sourcing standards — not as a standalone green light from a vendor's label.

This article is general information about how FDA's bulk substance risk categories work, not legal advice for your specific clinic. Substance status changes as FDA's review process and state enforcement positions evolve — confirm current status with your medical director and licensed counsel before making a sourcing decision.