Every pillar article on Peptidings documents the FDA status and WADA status of the compound it covers. These two designations answer two different questions that matter for two different reasons: FDA status tells you something about the compound’s legal and safety assessment landscape in the United States; WADA status tells you whether the compound is prohibited for athletes subject to anti-doping rules.
Both are frequently misunderstood. FDA Category numbers are confused with each other and with approval status. WADA prohibition is assumed to imply danger; WADA clearance is assumed to imply safety. Neither assumption is correct. This guide explains what these designations actually mean, how the relevant regulatory frameworks operate, what changed in 2023 that affected access to several compounds covered on this site, and what the regulatory landscape looks like internationally.
Table of Contents
- The FDA Regulatory Framework: An Overview
- FDA Bulk Drug Substance Categories: 1, 2, and 3 Explained
- FDA Approval vs. FDA Designation: Critical Distinctions
- What Changed in 2023: The Compounding Restrictions
- The WADA Prohibited List: How It Works
- Relevant WADA Sections for Peptides
- Regulatory Status of Compounds Covered on This Site
- International Regulatory Landscape
- The Regulatory Gray Area: What It Means in Practice
- Frequently Asked Questions
The FDA Regulatory Framework: An Overview
The U.S. Food and Drug Administration regulates drugs, biologics, and medical devices in the United States. A pharmaceutical compound can have multiple relationships with the FDA that are distinct from each other: it may be an approved drug, an investigational compound in clinical trials, a compound with orphan drug designation, a compound subject to compounding restrictions, or a compound with no formal FDA engagement at all.
FDA approval is the highest form of recognition—it means the agency has reviewed controlled trial evidence and determined that a drug is safe and effective for a specific indication. Approval is indication-specific: a drug approved for one condition is not automatically approved for other conditions, even if doctors prescribe it off-label for them.
Below FDA approval, there is a complex landscape of designations, pending reviews, and compounding regulations that affect how compounds are accessed and used in the United States. Understanding this landscape is particularly important for peptide research because many widely discussed compounds are not approved drugs and are accessed through compounding pharmacies—an avenue that has been significantly restricted in recent years.
FDA Bulk Drug Substance Categories: 1, 2, and 3 Explained
The FDA’s bulk drug substance category system applies to the compounding of drugs under sections 503A and 503B of the Federal Food, Drug, and Cosmetic Act. It determines which compounds compounding pharmacies are permitted to use in preparing non-commercially available drug preparations for individual patients or healthcare facilities. This is the primary regulatory mechanism through which many research peptides have been (or are no longer) accessible in the United States.
Plain English
The FDA sorts compounds into three categories that determine whether compounding pharmacies can make them. Category 1 means they can. Category 2 means they can’t anymore. Category 3 is still being evaluated. When a peptide moves to Category 2, it effectively disappears from legal US compounding pharmacy access.
Category 1: Nominated, Under Review
Category 1 compounds have been nominated by interested parties (compounding pharmacies, prescribers, researchers, or manufacturers) for inclusion on the 503A or 503B bulk drug substance lists and are currently under active FDA evaluation. While a compound is in Category 1 status, compounding pharmacies may continue to compound it while the review proceeds. Category 1 is essentially a holding status—the compound is in the FDA’s pipeline for evaluation, not yet formally approved for or prohibited from compounding.
BPC-157’s injectable form has been in Category 1 status, meaning compounding pharmacies could continue to prepare it pending the FDA’s review. The FDA’s evaluation could result in moving the compound to a formally approved list (permitting continued compounding) or to Category 2 (prohibiting compounding). Non-injectable BPC-157 preparations (oral) have been in different regulatory positions.
Category 2: Prohibited from Compounding
Category 2 represents an adverse FDA determination. When the agency places a compound in Category 2 under 503A or 503B, it has determined that there is insufficient evidence of clinical use, or that the compound presents concerns that make it inappropriate for compounding. Category 2 placement prohibits compounding pharmacies from preparing the compound for individual patient prescriptions or for healthcare facilities.
Thymosin Alpha-1’s 2023 Category 2 placement was the most significant compounding restriction for compounds covered on Peptidings in recent years. Before 2023, Thymosin Alpha-1 was accessible through US compounding pharmacies under prescriptions; after the Category 2 determination, this pathway was eliminated. The Category 2 designation does not mean the FDA has determined Thymosin Alpha-1 to be dangerous—it reflects an assessment of insufficient evidence for compounding-specific purposes by US regulatory standards, separate from its approved status in 35+ other countries.
Category 3 (Informal): Not Reviewed
The term “Category 3” is sometimes used informally to describe compounds that have not been nominated and are not on either the approved or prohibited lists. These compounds exist in a regulatory gray area—the FDA has not taken a formal position on them for compounding purposes. Many research peptides fall into this informal Category 3: KPV, LL-37, VIP, and others are not on the FDA’s nominal review lists and have no formal FDA classification for compounding use. This is not the same as being approved or cleared—it means no formal evaluation has occurred. The regulatory gray area has practical implications discussed in the final section of this guide.
FDA Approval vs. FDA Designation: Critical Distinctions
Several terms are commonly confused in discussions of FDA status. Getting these right matters because they represent very different levels of regulatory recognition.
FDA Approval (NDA / BLA)
FDA approval—through a New Drug Application (NDA) for small molecules or a Biologics License Application (BLA) for biologics—means the FDA has reviewed controlled clinical trial evidence and determined the drug is safe and effective for a specific indication. This is the highest form of FDA recognition and is what allows a drug to be marketed commercially in the United States. The GLP-1 receptor agonists (semaglutide, tirzepatide, liraglutide) are FDA-approved. Thymosin Alpha-1 is not FDA-approved for any indication.
Orphan Drug Designation (ODD)
Orphan Drug Designation is granted to compounds intended to treat rare diseases (affecting fewer than 200,000 people in the United States). ODD is a research incentive—it provides benefits including extended market exclusivity upon approval, tax credits for clinical trial costs, and expedited review—not an evaluation of the compound’s safety or efficacy. A compound with Orphan Drug Designation has not been assessed for approval; the FDA has determined only that the target disease qualifies as rare and that the compound may plausibly address it.
Thymosin Alpha-1 holds Orphan Drug Designation for four conditions (chronic hepatitis B, malignant melanoma, DiGeorge syndrome, and hepatocellular carcinoma). This is frequently misrepresented as evidence of FDA recognition of its efficacy—it is not. ODD is a designation, not an approval.
Breakthrough Therapy Designation, Fast Track, and Accelerated Approval
These are expedited regulatory pathways—mechanisms for faster review or earlier approval based on preliminary evidence in serious or life-threatening conditions. They represent FDA recognition that a compound is promising enough to warrant expedited attention, not that it has already met the safety and efficacy standard for full approval. A compound with Breakthrough Therapy Designation is further along in the regulatory process than one without it, but it is not approved until it completes the review process.
What Changed in 2023: The Compounding Restrictions
2023 was a significant year for the regulatory landscape of research peptides in the United States. The FDA issued final guidance on several bulk drug substances under the 503A and 503B compounding frameworks, including Category 2 determinations for compounds that had previously been accessible through compounding pharmacies.
Plain English
In 2023, the FDA moved several popular research peptides—including thymosin alpha-1 and others—to Category 2, meaning US compounding pharmacies can no longer legally prepare them. This was the single biggest regulatory shift affecting peptide accessibility in years.
The most consequential changes for compounds covered on this site were:
Thymosin Alpha-1 was placed on the Category 2 list for both 503A (for individual patient prescriptions) and 503B (for healthcare facilities). This eliminated the primary pathway through which US patients had been accessing it via compounding pharmacies under prescriptions. The change does not affect its approved status in other countries.
PT-141 (Bremelanotide) was similarly subject to Category 2 determination for compounding, though Bremelanotide is also FDA-approved (as Vyleesi for hypoactive sexual desire disorder in premenopausal women), meaning the approved commercial product remains available.
These changes reflect an ongoing FDA effort to assert regulatory clarity over the compounding landscape, which had expanded substantially during the period when many peptide compounds were freely accessible through compounding channels. The direction of regulatory travel—toward increased restriction rather than liberalization—is relevant for anyone following the accessibility of specific compounds in the US market.
The WADA Prohibited List: How It Works
The World Anti-Doping Agency (WADA) publishes an annual Prohibited List—the definitive list of substances and methods prohibited in sport under the World Anti-Doping Code. The list is updated annually and takes effect on January 1 of each year. Athletes competing under WADA-compliant anti-doping rules are subject to this list.
Plain English
WADA’s prohibited list is separate from the FDA. A compound can be FDA-approved and still banned in sport, or FDA-unapproved but not on WADA’s list. Athletes need to check both systems independently—one doesn’t tell you anything about the other.
WADA prohibition is not a safety determination. A compound can be prohibited because it provides performance enhancement even if it is completely safe; a compound can be permitted because it does not provide a performance advantage even if it has significant safety concerns. The Prohibited List is organized around three criteria: performance enhancement, health risk, and violation of the spirit of sport. A compound can be prohibited if it meets any two of these three criteria, or if the evidence for the first criterion is strong enough alone.
How Substances Get Added to the List
WADA’s List Committee reviews scientific literature and considers nominations from anti-doping organizations, national anti-doping agencies, and sports federations. A compound can be added even before it is widely available or commercially marketed if there is evidence that it is being used in sport and that it provides performance enhancement. This proactive approach means the Prohibited List sometimes includes compounds that have never completed clinical trials—WADA acts on evidence of use and potential enhancement, not on approved drug status.
Strict Liability
WADA operates under strict liability: an athlete is responsible for any prohibited substance found in their sample, regardless of how it got there. There is no good-faith exception—”I didn’t know it was prohibited” or “my supplement was contaminated” are mitigating factors that may reduce sanctions but do not eliminate them. Athletes must verify any substance they use against the current Prohibited List before ingesting it. The fact that a substance is legal, prescribed by a physician, or purchased from a reputable supplier does not protect against a positive test if it appears on the List.
Relevant WADA Sections for Peptides
| Section | Category | Relevance to Peptides |
|---|---|---|
| S0 | Non-approved substances | The most important section for peptide research. Prohibits any pharmacological substance that is not approved for therapeutic use by any regulatory authority and has no ongoing approved clinical trial. BPC-157 is prohibited here—it has no regulatory approval anywhere and no approved clinical trial. |
| S2 | Peptide hormones, growth factors, related substances and mimetics | Prohibits growth hormone, IGF-1, erythropoietin, and related compounds. TB-500 (Thymosin Beta-4) is prohibited here. This section also covers many GH secretagogues—not all are individually named but the section’s language covers compound classes. |
| S4 | Hormone and metabolic modulators | Covers GLP-1 receptor agonists (semaglutide, tirzepatide) and MK-677, among others. These are prohibited in-competition and out-of-competition. |
| S6 | Stimulants | Not typically relevant to research peptides; covers traditional stimulants and some neurotransmitter modulators. |
Section S0 is the broadest and most consequential section for the peptide research space. Its language—prohibiting any pharmacological substance not approved by any regulatory authority without an ongoing approved trial—effectively sweeps in every research compound that has no regulatory approval anywhere in the world. Because BPC-157 has no regulatory approval and no ongoing approved human trial, it falls under S0. This is not a case of WADA specifically targeting BPC-157; S0 is a catch-all for unapproved pharmacological agents used for performance purposes.
Regulatory Status of Compounds Covered on This Site
Note: Regulatory status changes. The FDA Prohibited List is updated annually; FDA bulk drug substance categories are subject to ongoing review. Verify current status against authoritative sources before making any decisions. This table reflects status as of early 2026 to the best of Peptidings’ knowledge.
| Compound | FDA Approval | FDA Compounding Category | WADA Status |
|---|---|---|---|
| Semaglutide (Ozempic/Wegovy) | Approved (diabetes, weight loss) | Approved drug | Prohibited (S4) |
| Tirzepatide (Mounjaro/Zepbound) | Approved (diabetes, weight loss) | Approved drug | Prohibited (S4) |
| Thymosin Alpha-1 | Not FDA-approved; approved in 35+ other countries; ODD for 4 conditions | Category 2 (2023)—compounding prohibited | Not prohibited |
| BPC-157 | Not approved anywhere | Category 1 (injectable, under review); Cat 1 (oral, under review) | Prohibited (S0) |
| TB-500 (Thymosin Beta-4) | Not approved; parent Tβ4 in ophthalmic trial pipeline | No formal Category designation known | Prohibited (S2, at all times) |
| GHK-Cu | Not approved; GRAS status for oral/topical | Oral/topical: GRAS; injectable: restricted | Not prohibited |
| MK-677 (Ibutamoren) | Not approved; has been in clinical trials | No formal Category designation; note: MK-677 is not a peptide | Prohibited (S4) |
| CJC-1295 (no DAC), Ipamorelin, Sermorelin | Not approved (Sermorelin was FDA-approved historically; approval lapsed) | Various; compounding restrictions have tightened on GH secretagogues | Prohibited (S2 / GH secretagogue category) |
| KPV, LL-37, VIP | Not approved anywhere | No formal FDA Category; regulatory gray area | Not prohibited |
International Regulatory Landscape
The regulatory landscape for research peptides varies significantly across jurisdictions, and the US framework described above does not apply globally. Several important generalizations hold across most markets, with exceptions:
In most countries, compounds not approved as pharmaceutical drugs are not legal for sale as therapeutic products intended for human use. The precise legal framework for possession and personal use of unapproved compounds for research purposes varies by jurisdiction. Many countries distinguish between “for research use” and “for human therapeutic use” in ways that affect what is permissible to purchase and possess but not to commercially distribute.
Some compounds that are restricted in the United States are prescription drugs with established approval in other markets. Thymosin Alpha-1 is the clearest example: restricted in the US since 2023, it is a licensed prescription medication in China, Italy, Singapore, and dozens of other countries. Readers in those jurisdictions have legal access to the pharmaceutical product through normal prescription channels—a very different situation from what a US reader faces.
The European Medicines Agency (EMA) regulates pharmaceutical approvals across EU member states. Several GLP-1 receptor agonists are EMA-approved. Research peptides generally face the same gray-area status in European countries as in the US—neither explicitly approved nor always explicitly prohibited for personal research use.
Peptidings does not provide legal advice, and the legal status of obtaining and possessing specific compounds is the reader’s responsibility to verify for their specific jurisdiction. The regulatory landscape changes—what was accessible in one year may not be accessible the next, and vice versa. Regulatory status sections in pillar articles reflect the state of knowledge at the time of writing and may not capture subsequent changes.
The Regulatory Gray Area: What It Means in Practice
Much of the research peptide space exists in what practitioners call a “gray area”—compounds that are not approved pharmaceutical drugs, not explicitly scheduled controlled substances, and not formally prohibited or permitted for personal research use by a clear regulatory framework. This gray area is not a stable state; it is a product of regulatory capacity constraints and is subject to narrowing as the FDA and other agencies continue to assert regulatory clarity.
The gray area does not mean “legal” in a positive sense. It means the regulatory framework has not formally addressed the specific question of personal research use. A person who purchases and uses an unapproved research peptide for personal use is not operating under explicit regulatory permission—they are operating in an area where the rules are unclear and where regulatory evolution continues to occur.
For researchers and informed adults, understanding the gray area means understanding that the regulatory landscape for the compounds you are researching may change—and that the direction of change in the United States has been toward greater restriction, not greater liberalization. Planning for that direction of travel is prudent.
Frequently Asked Questions
If WADA doesn’t prohibit something, does that mean it’s safe?
No. WADA’s Prohibited List is an anti-doping document, not a safety assessment. Compounds are on or off the list based on performance enhancement potential, health risk, and violation of the spirit of sport. Many compounds with genuine safety concerns are not prohibited by WADA because they do not provide meaningful performance enhancement. WADA status is not a safety endorsement. LL-37’s cancer biology concerns, VIP’s hypotension risk, and KPV’s lack of human safety data are all independent of WADA’s listing decisions.
Does Orphan Drug Designation mean the FDA thinks something works?
No. Orphan Drug Designation means the FDA has determined that a disease qualifies as rare (under 200,000 US patients) and that a compound may plausibly address it. ODD is a research incentive—it provides benefits to encourage development for rare diseases—not an efficacy assessment. Thymosin Alpha-1 has four ODD designations; it has never received FDA approval for any of them. The designations and the approvals are entirely separate.
BPC-157 is Category 1—does that mean it’s approved for compounding?
Category 1 means it is under active FDA review and compounding may continue during that review—not that it has been approved for compounding. A Category 1 designation can be resolved in either direction: the FDA may determine the compound is appropriate for compounding (moving it to an approved list) or inappropriate (moving it to Category 2). The Thymosin Alpha-1 Category 2 determination in 2023 illustrates what Category 1 resolution can look like.
I’m not a competitive athlete. Do WADA rules apply to me?
If you are not subject to WADA-compliant anti-doping testing—you do not compete in a sport governed by a WADA signatory organization, or you have retired from such competition—WADA’s Prohibited List does not govern what you can use. WADA is an anti-doping organization, not a public health or law enforcement body. Its rules apply to athletes in competitive sports; they have no legal force outside that context. The relevant legal questions for non-athletes are governed by the FDA and the applicable laws of their jurisdiction.
How often is the WADA Prohibited List updated?
The WADA Prohibited List is updated annually and takes effect January 1 of each year. WADA may also issue addenda during the year for urgent additions. Athletes should verify against the current year’s list—not archived versions—and should use WADA’s Global DRO (Drug Reference Online) tool for substance-specific queries. What was permitted in a prior year may be prohibited in the current year.