What exactly is a peptide, why would someone inject themselves with one, and what does all of this have to do with the department of health and human services (HHS)? These are the questions everyone seems to be asking, so here are your answers.

When you take a cluster of amino acids and chain them together, you get a peptide. While peptides are smaller in size than their protein counterparts, your body still frequently uses them to trigger reactions and signal activity. When you feel hunger, that’s the release of ghrelin (a peptide) telling you it’s food time. After you’ve eaten, the body releases glucagon-like peptide-1 (GLP-1) which helps regulate the insulin response and taper hunger levels. And yes, that’s the same GLP-1 which is mimicked in drugs like semaglutide or tirzepatide which people use for weight loss.

While some peptides can be taken orally, injectable peptides are what have received increasing attention. The most popular of these carry alpha-numeric designations that sound awkwardly similar to droids from the Star Wars franchise; BPC-157, TB-500, and MOTs-C. Joking aside, there has been mixed messaging regarding their use. Online influencers anecdotally promote injectable peptides as a method to boost muscle development, promote injury recovery, or extend cellular lifespan. Healthcare professionals and scientists are more reserved and note there is very little evidence for these claims.

Adding to this confusion is the recent HHS decision to roll back the 2023 “Category 2” designation for 12 of these peptides. Within the FDA, a Category 2 designation means there is a higher safety risk and it restricts opportunities for use in compounded medications.

Policy wise, there is plenty to unpack in this decision. What is a compounded drug? Why does this matter in the peptide debate? What does the evidence say about peptides?

But most important, what does it mean for you?

Let’s discuss.

Why the FDA moved certain peptides into Category 2 in 2023

By their nature, anything which is injected is usually higher risk than something taken orally or topically, with an increased risk of infection, bruising, or triggering a reaction with the compound delivered straight into the bloodstream. So injectable peptides already start from a rough patch, but the risk was further heightened with three central issues of safety.

First, the issue of immunogenicity, the possibility that the peptides could trigger an immune reaction. If a peptide is mistaken for an invader or a pathogen, it prompts an immune response with either mild symptoms, like hives, or something much worse, like anaphylactic shock. Either way, you want evidence that a peptide will not trigger an immune reaction for a majority of people.

Second, the FDA had concerns for how producers would consistently source and adequately identify the active ingredient. Third, there was limited safety data in humans, or, suspected possibility for harm with select peptides. Examples like Cathelicidin LL-37 reported some evidence it could damage the male reproductive system, while Melanotan II resulted in adverse events in several case reports, including melanoma and priapism.(1)

What are compounded drugs?

To better understand compounded drugs, let’s start with an explanation of an FDA-approved drug.

When a drug has been approved for use by the FDA, it means it has been rigorously evaluated for safety, efficacy, and quality and may be legally sold and distributed.(2) FDA approval for drugs is a fantastic process because the engineered medicine in question will reliably and consistently do its job to treat, prevent, or cure a certain condition. By contrast, a compounded medication refers to a specialized or custom-prepared treatment and is not FDA-approved. However, the FDA still permits sales a compounded drug when it meets the specified needs of a patient’s condition, and there is no FDA-approved alternative.

Present advice is that compounded drugs should only be used for situations where no alternative FDA-approved drug can be used, and they should be obtained from licensed facilities which meet quality standards.(3) While not FDA-approved, there still is some oversight for what may be included in a compounded medication. This is where the news announcement for peptides comes in play, as there is now a possibility for these peptides to be added to the 503A bulks list, which would expand compounding options.

What is the 503A bulks list?

The FDA maintains what is called the 503A bulks list, a list of active ingredients that licensed pharmacies and physicians are allowed to use when making compounded drugs. This is neither a safety nor efficacy designation; it’s simply a legal framework that allows use of the ingredients when producing compounded drugs.

This matters for the present conversation because now that the peptides in question have been removed from the Category 2 designation, they are now eligible for placement on to the 503A bulks list. However, that decision will be left to the pharmacy compounding advisory committee when they meet in July.

What changed in 2026?

This news generated a lot of buzz as to what changed between now and 2023, and the simple answer is that there was a reversal in policy, not a redirection through new evidence. The new administration reasoned that the Category 2 designation had produced a black-market demand. By restricting the peptides, people were going through more desperate and illegal channels for acquisition, and with absolutely no safety standard in place (black markets are not well known for their public safety record), this increased the danger.

Despite the prior Category 2 designation, injectable peptides could previously be acquired through “gray market” options, such as overseas distributors, or vendors selling with the explicit declaration that the product was intended for “research purposes”. Now, with the potential for adding the peptides to the 503A bulks list, this repositions the conversation through legal channels that would, optimistically, improve production standards.

What does this mean for consumers?

The most important detail everyone needs to know is that this policy move is neither a stamp of approval nor certification of safety. There are two major questions still pending regarding injectable peptides.

The first question is whether or not these peptides actually work. Remember, peptides are a category, so scientific evidence is distinct for each one. Insulin, for example, is an injectable peptide we use as medication for people with diabetes, and has millions of data from millions of research participants highlighting its benefits. The same cannot be said for something like BPC-157, which is purported to assist with tendon and muscle injury. Plenty of experiments conducted in rats and petri-dish cellular tissue have reported how this peptide may have an effect, but the data from human trials reporting positive outcomes is limited, at best.(4)

Judge for yourself, however. So far, there appear to be only three published, peer-reviewed studies, with a collective participant population of 30 people. In one study, there was improved knee pain, while another reported resolution of interstitial cystitis (bladder pain), and the third reported no changes at all. In each of these studies, patients received treatments in addition to the BPC-157, and there were no control groups for comparison.(5–7) Animal models are a good start, but they can only tell you so much about how a treatment may (or may not) work in a human.

The second major question is what this means for the availability of these peptides, and for that, the future is unclear. With the upcoming review in July, there is a possibility that these peptides could be added to the 503A bulks list, and that would definitely expand their use in compounded medications. This would likely lead to future questions pertaining to sourcing quality, but even if more opportunities arise, consumers should always be wary regarding quality issues. Whether or not use of injectable peptides increases in the wellness sphere remains to be seen, but as always, consumers should stay informed and expect consistency from providers with a history of creating safe and high-quality products.

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. 

Dustin Moore is a nutrition scientist, dietitian, and public health professional dedicated to advancing evidence-based practice. He holds a PhD in Public Health and is deeply invested in enhancing scientific communication to bridge the gap between the health science and the public.

1. FDA. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. FDA [Internet]. 2026 Apr 27 [cited 2026 Apr 28]. Available from: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
2. FDA O of the. Is It Really “FDA Approved”? FDA [Internet]. 2025 Feb 5 [cited 2026 Apr 28]. Available from: https://www.fda.gov/consumers/consumer-updates/it-really-fda-approved
3. FDA C for DE and. Compounding and the FDA: Questions and Answers. FDA [Internet]. 2025 Sep 16 [cited 2026 Apr 28]. Available from: https://www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers
4. McGuire FP, Martinez R, Lenz A, Skinner L, Cushman DM. Regeneration or Risk? A Narrative Review of BPC-157 for Musculoskeletal Healing. Curr Rev Musculoskelet Med. 2025 Aug 12;18(12):611–9. doi:10.1007/s12178-025-09990-7 PubMed PMID: 40789979; PubMed Central PMCID: PMC12446177.
5. Lee E, Burgess K. Safety of Intravenous Infusion of BPC157 in Humans: A Pilot Study. Altern Ther Health Med. 2025 Sep;31(5):20–4. PubMed PMID: 40131143.
6. Lee E, Padgett B. Intra-Articular Injection of BPC 157 for Multiple Types of Knee Pain. Altern Ther Health Med. 2021 Jul;27(4):8–13. PubMed PMID: 34324435.
7. Lee E, Walker C, Ayadi B. Effect of BPC-157 on Symptoms in Patients with Interstitial Cystitis: A Pilot Study. Altern Ther Health Med. 2024 Oct;30(10):12–7. PubMed PMID: 39325560.