Peptide Therapy 101: What Peptides Are, What the Evidence Shows and the Regulatory Picture

Insulin is a peptide. So are semaglutide and tirzepatide, two of the most talked-about medications of the decade. So is BPC-157, a compound you can buy online in a vial labeled “not for human consumption.” That single word, “peptide,” covers everything from life-saving drugs to products with almost no human data.

This primer explains what peptides are, how they’re regulated, why the FDA has restricted certain ones, and the questions I encourage patients to ask before starting any peptide.

What is a peptide?

A peptide is a short chain of amino acids — the same building blocks that make up proteins, just fewer of them. Your body makes thousands of peptides that act as signals: hormones that regulate blood sugar, appetite, growth, sleep and healing. Because they act on specific receptors, peptides can have targeted effects, which is what makes them attractive as medicines.

Most peptides are broken down in the digestive tract, so many are given by injection under the skin.

Three very different categories

1. FDA-approved peptide medications

These have passed clinical trials and manufacturing review. Examples include insulin, GLP-1 medications such as semaglutide and tirzepatide, tesamorelin (approved for a specific fat-distribution condition in people with HIV), and bremelanotide (approved for low sexual desire in certain premenopausal women). For approved uses, we know the dose, the benefits and the risks.

2. Compounded peptides

Licensed compounding pharmacies can prepare some peptides under a prescription, but only if the ingredient meets federal rules. The FDA maintains lists that evaluate bulk substances nominated for compounding. In 2023, it placed a number of popular peptides — including BPC-157 and several growth hormone–releasing peptides — in a category of substances that raise significant safety concerns, meaning compounders generally should not use them. The lists can change as nominations are reviewed, so the status of any single peptide is worth checking at the time you’re considering it.

3. “Research use only” products

These are sold online without a prescription, often with a disclaimer that they aren’t for human use. They are not made to pharmaceutical standards, and independent testing of such products has found wrong ingredients, wrong amounts and contamination. I advise patients not to inject them.

What the evidence actually shows

The evidence varies widely by peptide:

• Strong: approved medications for their approved uses.
• Limited: some growth hormone secretagogues raise growth hormone levels in small studies, but long-term benefits and safety for healthy adults aren’t established.
• Mostly animal data: many healing and “anti-aging” peptides, including BPC-157, have promising animal research but very little human trial data.

“Promising in rats” is a reason to keep studying something. It’s not proof that it works or is safe in people.

Risks and who should avoid peptides

• Injection-site reactions, infection from non-sterile products, and allergic reactions.
• Effects on blood sugar, fluid retention and hormone levels with growth hormone–related peptides.
• A theoretical concern that growth-promoting peptides could stimulate existing cancers; anyone with a history of cancer should avoid them unless an oncologist agrees.
• Pregnancy and breastfeeding: avoid unless specifically prescribed.
• Competitive athletes: many peptides are prohibited by the World Anti-Doping Agency.

Questions to ask any peptide provider

1. Is this peptide FDA-approved, and if so, for what?
2. If it’s compounded, which pharmacy makes it, and is the ingredient permitted for compounding?
3. What human evidence supports using it for my goal?
4. What lab work and follow-up will monitor my safety?
5. What are the alternatives with stronger evidence?

At our Hudson location, peptide therapy is offered only after a medical evaluation, with a clear discussion of evidence and regulatory status, and within our broader longevity approach.

Frequently asked questions

Are peptides the same as steroids?

No. Peptides are short amino acid chains that act as signals. Anabolic steroids are a different class of hormones.

Is BPC-157 legal?

The FDA has listed it among substances that raise significant safety concerns for compounding, and it is not FDA-approved. Products sold online as research chemicals are not regulated for human use.

Can I take peptides by mouth?

Most peptides are broken down in the digestive tract, so many are injected. A few approved medications use special oral formulations.

How do I know if a peptide is right for me?

Start with a medical evaluation that reviews your goals, health history and evidence-based alternatives.

Learn more at a consultation

If you’re curious about peptides, I invite you to a complimentary, no-commitment consultation at our Hudson location.

• Hudson, OH: 50 W Streetsboro St, Suite 2 · (330) 460-5915

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References: U.S. Food and Drug Administration. Bulk drug substances nominated for use in compounding under section 503A of the FD&C Act (Category 2: substances that raise significant safety risks). FDA. · Falutz J, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. New England Journal of Medicine. 2007. · World Anti-Doping Agency. The Prohibited List. WADA.

This article is for general information only and is not medical advice. Treatments are provided only after consultation and evaluation by a licensed provider. Individual results vary.