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Peptide Therapy: What is it?

Educational Overview

Peptide Therapy: What It Is and What the Research Shows

Originally published 1/12/2024 · Updated 10/6/2026

Peptides are short chains of amino acids, and “peptide therapy” has become a popular phrase. But it covers very different things: a few FDA-approved medicines with labeled uses and warnings, and many other compounds marketed without FDA approval. This article explains the difference, what the FDA has said, and what remains unknown.

Important

  • Only some peptides are FDA-approved drugs, and only for specific, labeled uses. Many peptides marketed online, including BPC-157, TB-500, ipamorelin, and CJC-1295, are not FDA-approved for any use.
  • The FDA has described safety concerns about certain compounded peptides[1].
  • Compounded medications are not FDA-approved and have not been evaluated by the FDA for safety, effectiveness, or quality.
  • Nothing here is medical advice, a recommendation, or a promise of results. See our FDA Peptide Review for the regulatory outlook.

At a Glance

FDA-approved peptide drugs Peptides marketed without FDA approval
Examples Semaglutide (Wegovy), a GLP-1 receptor agonist[2]; tesamorelin (Egrifta SV)[3] BPC-157, TB-500, ipamorelin, CJC-1295, and others
Approved for Specific, labeled uses only, such as chronic weight management in adults meeting BMI criteria[2], or excess abdominal fat in HIV-infected adults with lipodystrophy[3] No FDA-approved use
Evidence Reviewed by the FDA before marketing, with prescribing information and warnings Mostly laboratory, animal, or small studies. FDA has raised safety concerns about certain compounded peptides[1]

Explore the Topic

Open any section below to learn more.

What are peptides?
▼

Peptides are short chains of amino acids, the building blocks of proteins. The body makes many of them naturally, and several act as hormones or signaling molecules. Insulin is a familiar example. Because they are small and specific, peptides have long been a source of drug candidates.

“Peptide therapy” is a broad phrase. It can refer to FDA-approved medicines with decades of evidence, or to compounds sold with little human research behind them. The distinction matters, which is why this article separates the two.

FDA-approved peptide drugs: two examples
▼

Semaglutide (Wegovy) is a GLP-1 receptor agonist approved as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial BMI of at least 30, or at least 27 with a weight-related condition. Its label carries a boxed warning about thyroid C-cell tumors seen in rodents, and it is contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN 2[2].

Tesamorelin (Egrifta SV) is approved for reducing excess abdominal fat in HIV-infected patients with lipodystrophy. Its labeling says it is not intended for general weight loss management, and lists contraindications including active malignancy and pregnancy[3]. For more, see our ipamorelin vs. tesamorelin article.

Peptides without FDA approval
▼

Many peptides discussed online, including BPC-157, TB-500, ipamorelin, CJC-1295, and others, are not approved by the FDA for any use. Claims you may see about weight loss, muscle building, recovery, or endurance for these compounds have not been established through FDA review.

We have written about several of them in more depth: BPC-157 vs. TB-500, ipamorelin vs. tesamorelin, thymosin alpha-1, and peptides and brain health.

Why the FDA has raised concerns
▼

On its page about certain bulk drug substances that may present significant safety risks (updated April 22, 2026), the FDA describes several concerns about compounded peptides in that category[1]:

Immunogenicity: for certain routes of administration, aggregation and peptide-related impurities may raise the risk of immune reactions.
Characterization: some peptides contain unnatural amino acids, which add to the complexity of confirming what is in a product.
Limited safety data: for most of the peptides, the FDA says it has no, or only limited, safety information and cannot tell whether they would cause harm in people.
Adverse events: for ipamorelin and certain others, the FDA references published reports of serious adverse events, including death, although causality is unclear in some instances.

These are the FDA’s stated concerns, not our own findings.

How peptide compounding is regulated
▼

Compounded drugs are prepared by licensed pharmacies for individual patients and are not FDA-approved. Which bulk substances pharmacies may compound under Section 503A is decided through a formal process that includes review by the FDA’s Pharmacy Compounding Advisory Committee (PCAC). For example, in December 2024 the committee voted 17 to 4 against adding thymosin alpha-1 to the 503A bulks list[4].

Advisory votes are non-binding, and the situation continues to change. We track it in our FDA Peptide Review.

What the evidence can — and can’t — tell us
▼
What has been found What is still unknown
A small number of peptide drugs are FDA-approved for specific uses[2][3]. Whether other peptides, sold without approval, are safe or effective for the uses they are marketed for.
The FDA has described safety concerns about certain compounded peptides[1]. The long-term safety of most of those peptides in people.
Regulators review peptides case by case[4]. How the regulatory picture will change as FDA rule-making continues.
Safety Considerations
▼
  • Approved does not mean risk-free. Even FDA-approved peptide drugs carry warnings and contraindications[2][3]. Review them with a licensed clinician.
  • Peptides without FDA approval have not been through the FDA process, and the agency has described safety concerns, including immunogenicity and limited safety data[1].
  • “Research Use Only” and unlicensed sources carry risks of wrong contents, wrong dose, contamination, or no sterility testing.
  • Injectable products can cause injection-site reactions and, rarely, severe allergic reactions. Seek emergency care for hives, wheezing, difficulty breathing, or swelling of the face, lips, tongue, or throat.
  • Pregnancy, breastfeeding, cancer history, and other medicines: discuss with a licensed clinician before considering any peptide. Tell your clinician about all medications and supplements you take.
  • Athletes: many peptides are prohibited by anti-doping rules. Check the current WADA list.

Our Perspective

This section is editorial. “Peptide therapy” is a label that can describe very different things. If you come across any peptide from any source, we suggest asking three questions:

  1. Is it FDA-approved, and for what? If so, ask to see the labeled indication and warnings.
  2. What is the evidence, in people? Ask which study supports the claim, how large it was, and whether it was in humans or animals.
  3. Who prepared it, and how was it tested? Ask about the source and third-party testing.

Have questions about peptide research?

Talk with our clinical team about your questions, in person or via telemedicine.

Call (561) 214-3323

Referenced Research

1

The FDA describes safety concerns about certain bulk drug substances, including peptides, nominated for compounding. It states that compounded peptides may pose a risk of immunogenicity for certain routes of administration because of aggregation and peptide-related impurities, that unnatural amino acids complicate characterization, and that for most of the peptides it has no, or only limited, safety information. For ipamorelin and certain others, it references published reports of serious adverse events including death, with causality unclear in some instances.

U.S. Food and Drug Administration. “Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks.” Updated April 22, 2026. fda.gov

2

Wegovy (semaglutide), a GLP-1 receptor agonist, is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial BMI of at least 30 kg/m², or at least 27 kg/m² with at least one weight-related condition. The label carries a boxed warning about thyroid C-cell tumors in rodents and is contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2.

U.S. Food and Drug Administration. “WEGOVY (semaglutide) injection, prescribing information.” June 2021. accessdata.fda.gov

3

A clinical policy summarizing the prescribing information for tesamorelin (Egrifta SV) states that it is indicated for the reduction of excess abdominal fat in HIV-infected patients with lipodystrophy. Limitations of use include that it is not intended for general weight loss management. Contraindications include disruption of the hypothalamic-pituitary axis, active malignancy, pregnancy, and hypersensitivity to tesamorelin or mannitol.

Clinical Policy: Tesamorelin (Egrifta SV), summarizing FDA-approved prescribing information. Meridian Health Plan. View document

4

At its December 4, 2024 meeting, the FDA’s Pharmacy Compounding Advisory Committee voted 4 yes and 17 no on including thymosin alpha-1 (free base) on the 503A bulks list, and the same on thymosin alpha-1 acetate. Members voting no cited the absence of compelling evidence of clinical effectiveness and safety for the uses reviewed.

U.S. Food and Drug Administration. “Final Summary Minutes, Pharmacy Compounding Advisory Committee Meeting, December 4, 2024.” fda.gov/media/185642/download

Important Disclosures

  • This article is for educational purposes only and is not medical advice. These statements have not been evaluated by the U.S. Food and Drug Administration. Nothing on this site is intended to diagnose, treat, cure, or prevent any disease.
  • Peptides discussed here other than the FDA-approved drugs named are not FDA-approved. Compounded medications are not FDA-approved and have not been evaluated by the FDA for safety, effectiveness, or quality.
  • The regulatory situation is evolving. The “Our Perspective” section is editorial and does not represent FDA policy.
  • Treatment decisions are made solely by an independent, licensed clinician after an individualized evaluation, and a doctor-patient relationship is established only after a qualifying consultation. Individual results vary.

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