The Patient’s Guide to Peptide Therapies in the Age of GLP-1s
By now, most Americans have heard of semaglutide and tirzepatide — the GLP-1 medications sold under names like Ozempic, Wegovy, and Zepbound. What fewer people know is what these drugs actually are at a biological level: peptides. And that distinction is starting to matter, because GLP-1s have opened a door to a much broader category of therapies that patients are now encountering — and asking their doctors about — every day.
That curiosity is a good thing. And it’s about to get louder. Last week, HHS Secretary Robert F. Kennedy Jr. announced plans to reverse a 2023 FDA decision that banned nearly two dozen peptides from being produced by compounding pharmacies — signaling that as many as 14 of those compounds could soon become accessible again. More access to emerging therapies, when paired with real clinical oversight, can be a meaningful step forward for patients. But access without understanding is where things go wrong. Public understanding hasn’t kept pace with demand — and when patients make consequential health decisions without the right information, the stakes are real.
What peptides actually are
Peptides are short chains of amino acids — the same building blocks that make up proteins. The body produces them naturally. They function as signaling molecules: regulating inflammation, stimulating hormone release, controlling appetite, supporting tissue repair. Pharmaceutical researchers have studied and synthesized peptide compounds for decades.
Some of the most widely prescribed medications in the country are technically peptides. Insulin is one. GLP-1 receptor agonists are another. Their success has made patients curious about what else exists in this category — and the wellness industry has moved aggressively to meet that curiosity, not always with accurate information.
“GLP-1s have done something important: they’ve made people realize that targeted biological therapies exist and that they work,” says Jessica Duncan, M.D., a board-certified obesity medicine physician. “The follow-on question — what else is out there? — is a reasonable one. But the answers require a clinical conversation, not a Google search.”
This is not one category. It’s three very different ones.
The most important thing patients don’t understand about peptides is that not all of them occupy the same regulatory space — and that difference matters enormously.
Some peptides are FDA-approved for specific indications and have cleared the full evidentiary bar that designation requires. GLP-1 medications fall here for obesity and type 2 diabetes. Others are available through compounding pharmacies for off-label use under physician supervision — a legitimate but more complex category that requires a clinician actively overseeing your care. Still others are sold as dietary supplements with minimal regulatory oversight and widely variable quality control.
These are not equivalent. The evidence base, the safety monitoring, and the clinical accountability differ substantially across all three.
A 2023 analysis published in JAMA found that the supplement industry — which includes many peptide products — frequently makes claims that outpace available evidence. The Federal Trade Commission has taken action against companies marketing peptide and hormone products with unsupported health claims.
“The biggest risk I see is patients conflating these categories,” Dr. Duncan says. “Something being sold as a peptide supplement and something being prescribed as a peptide therapy by a physician are very different things, even if the marketing sounds similar.”
What the evidence actually supports
The clinical evidence for peptide therapies is uneven — and understanding that unevenness matters before drawing conclusions about any specific compound.
GLP-1 receptor agonists have large, peer-reviewed randomized controlled trials behind them. The data on weight loss, cardiovascular risk reduction, and glycemic control is among the strongest in obesity medicine. That level of evidence does not exist for most other peptides circulating in wellness conversations right now.
Some peptides have promising early data from animal models or small human studies. Others have more established research in specific clinical contexts — such as growth hormone-releasing peptides studied in the context of diagnosed deficiencies — that does not automatically translate to general wellness use. Physician organizations including the Endocrine Society have called for more standardized clinical guidance as these therapies become more widely sought.
Five questions to ask before starting any peptide therapy
For patients who encounter peptide therapies — whether through a physician referral, a telehealth platform, or a wellness provider — Dr. Duncan recommends asking these questions before moving forward:
- Is this FDA-approved, and for what condition? Regulatory status is a meaningful signal of how much evidence exists for a given compound and use case.
- What does the clinical evidence show for my specific goal? A peptide with solid research for one application may have little or no research for another. Mechanism of action does not automatically transfer across indications.
- What are the risks and contraindications? Peptides affect biological signaling pathways and can interact with other medications, underlying conditions, or hormonal systems.
- Who is overseeing my care? Peptide therapies managed by a licensed clinician with relevant expertise carry a meaningfully different risk profile than self-directed supplementation or protocols obtained without medical oversight.
- How will we measure whether this is working? A physician should define what a successful outcome looks like and how it will be tracked — and should be willing to discontinue a therapy that isn’t producing the intended result.
The bottom line
The mainstreaming of GLP-1 medications has legitimized patient interest in a broader class of therapies that most people knew nothing about five years ago. That is, on balance, a positive development for medicine. But it has also created a consumer market where the distance between rigorous clinical science and aggressive wellness marketing can be very hard to see.
This isn’t about slowing people down. It’s about making sure that when patients take that next step, they’re doing it with a real physician in their corner — not just a supplement shelf and a search engine.
“The patients who do best are the ones who treat this as a medical decision,” Dr. Duncan says. “That means understanding what you’re taking, why, and having a qualified physician helping you make that call.”
For anyone curious about whether peptide therapies are relevant to their health, that’s the right starting point: a physician with experience in metabolic or hormonal health. The conversation is worth having. Just make sure it’s with the right person.
Jessica Duncan, M.D., D.A.B.O.M., is a board-certified obesity medicine physician specializing in metabolic health and weight management.
