If I’d heard the term “peptides” tossed around at parties years ago, I’d be taken back to high school chemistry when I first learned about peptides, short chains of amino acids (AKA the building blocks of protein).
Peptide therapies can be manipulated to mimic or impact naturally occurring signaling molecules, allowing them to target numerous biological pathways, such as appetite control and blood sugar. Insulin, for example, is a peptide hormone.
Today, peptides mean much more in mainstream wellness culture. These strings of amino acids are being promoted for everything from anti-aging to weight loss, muscle recovery, improved sleep, and tissue repair. But does research support their use?
FDA-approved Peptides
Popular evidence-based peptides include semaglutide and tirzepatide, two of the most common GLP-1 weight loss drugs. In a 2021 New England Journal of Medicine trial involving nearly 2,000 adults with overweight or obesity, weekly semaglutide along with lifestyle intervention produced substantial weight loss over 68 weeks. 1
In addition, the 2022 SURMOUNT-1 trial found that tirzepatide produced substantial and sustained weight reduction over 72 weeks, with improvements in several cardiometabolic measures. 2
Weight loss results have also been positive in a 2024 study of 210 Chinese overweight and obese adults. 3 The most common side effects with GLP-1 peptide therapies are GI-related, including nausea, abdominal pain, and gas.
Investigational Peptides
Peptides may also offer potential applications in tissue repair and recovery. For example, BPC-157 has generated considerable interest because animal studies suggest effects on inflammation, blood vessels, and tissue healing. 4
Unfortunately, the human evidence remains much weaker. A 2025 systematic review identified 36 relevant BPC-157 studies, but only one clinical study; the remaining 35 were preclinical. 5
A very small 2025 pilot study involving only two subjects reported that intravenous BPC-157 was tolerated without measurable adverse effects, but such a tiny study can’t establish long-term safety or effectiveness. 6
A peptide showing promising results in lab or animal research isn’t necessarily effective—or safe—in humans. Recent reviews continue to label BPC-157 and several other popular peptides as investigational, without adequate large-scale controlled trials to confirm their benefits.
Other lab-created peptides include TB‑500, KPV, MOTS‑C, CJC‑1295 / Ipamorelin, Tesamorelin, GHK‑Cu, NAD+ blends, Semax, Selank, AOD‑9604, 5‑Amino‑1MQ. Some peptides recently had restrictions loosened (e.g., BPC‑157, KPV, TB‑500, MOTS‑C), but this does not mean they’re proven safe.
Quality-control and regulatory concerns still exist. FDA-approved peptide medications undergo extensive testing for identity, purity, dosage, efficacy, and safety. Unapproved peptides bought online or supplied through other compounding channels may not receive equal oversight.
The FDA specifically warns that compounded products, such as those mentioned above, don’t undergo its premarket review for safety, effectiveness, or quality. It has also reported dosing errors and hospitalizations linked to compounded injectable semaglutide.
Other concerns include impurities and immune reactions. A 2025 review notes that impurities introduced during peptide manufacturing can lead to immune reactions, while a 2024 regulatory review emphasized the challenge of adequately labeling peptide-related impurities and evaluating their toxicological effects. 7, 8
Bottom Line
Peptides are neither inherently “good” nor “bad.” Some have research-backed, clinical evidence and legitimate medical uses, while others are still experimental despite aggressive wellness marketing.
Consumers should separate FDA-approved peptide medicines supported by randomized clinical trials from experimental compounds with limited human research.
For anyone considering peptide therapy, the safest approach is to discuss the specific compound, source, dose, known risks, and evidence with a qualified healthcare professional rather than relying on flashy marketing claims.
Lisa Andrews, MEd, RD, LD
References:
1. Wadden TA, Bailey TS, Billings LK, Davies M, Frias JP, Koroleva A, Lingvay I, O'Neil PM, Rubino DM, Skovgaard D, Wallenstein SOR, Garvey WT; STEP 3 Investigators. Effect of Subcutaneous Semaglutide vs Placebo as an Adjunct to Intensive Behavioral Therapy on Body Weight in Adults With Overweight or Obesity: The STEP 3 Randomized Clinical Trial. JAMA. 2021 Apr 13;325(14):1403-1413. doi: 10.1001/jama.2021.1831. PMID: 33625476; PMCID: PMC7905697.
2. Jastreboff AM, Aronne LJ, Ahmad NN, Wharton S, Connery L, Alves B, Kiyosue A, Zhang S, Liu B, Bunck MC, Stefanski A; SURMOUNT-1 Investigators. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022 Jul 21;387(3):205-216. doi: 10.1056/NEJMoa2206038. Epub 2022 Jun 4. PMID: 35658024.
3. Zhao L, Cheng Z, Lu Y, Liu M, Chen H, Zhang M, Wang R, Yuan Y, Li X. Tirzepatide for Weight Reduction in Chinese Adults With Obesity: The SURMOUNT-CN Randomized Clinical Trial. JAMA. 2024 Aug 20;332(7):551-560. doi: 10.1001/jama.2024.9217. Erratum in: JAMA. 2024 Aug 20;332(7):595. doi: 10.1001/jama.2024.12249. PMID: 38819983; PMCID: PMC11337071.
4. Vasireddi N, Hahamyan H, Salata MJ, Karns M, Calcei JG, Voos JE, Apostolakos JM. Emerging Use of BPC-157 in Orthopaedic Sports Medicine: A Systematic Review. HSS J. 2025 Jul 31;21(4):485-495. doi: 10.1177/15563316251355551. PMID: 40756949; PMCID: PMC12313605.
5. BPC-157 IV Safety Pilot: First Human Data Published (2025)
6. Mattei AE, Roberts BJ, Lelias S, Miah S, Howard KE, Weaver JL, Verthelyi D, Pang ES, Edwards K, De Groot AS. Immunogenicity risk assessment of peptide-related impurities identified in generic teriparatide products. Front Immunol. 2025 Dec 8;16:1730346. doi: 10.3389/fimmu.2025.1730346. PMID: 41445733; PMCID: PMC12722964.
7. Investigation of Impurities in Peptide Pools
8. Ashraf AR, Mackey TK, Vida RG, Kulcsár G, Schmidt J, Balázs O, Domián BM, Li J, Csákó I, Fittler A. Multifactor Quality and Safety Analysis of Semaglutide Products Sold by Online Sellers Without a Prescription: Market Surveillance, Content Analysis, and Product Purchase Evaluation Study. J Med Internet Res. 2024 Nov 7;26:e65440. doi: 10.2196/65440. PMID: 39509151; PMCID: PMC11582493.