It feels like peptides are suddenly – and quite literally – everywhere.
Friends are talking about which peptides they’re taking for recovery, muscle, body fat or longevity. People have small vials stored in their refrigerators, mixing and injecting them at home. Wellness clinics and telehealth companies offer peptides. And they’re remarkably easy to buy online.
Which raises a pretty basic question: What exactly are we all talking about when we say “peptides”?
Because they aren’t all the same.
What exactly are peptides? Peptides are short chains of amino acids that act as signaling molecules in the body, essentially carrying instructions between cells. And peptide therapy isn’t new or fringe. Insulin is a peptide. So are GLP-1 medications such as semaglutide. These are FDA-approved drugs backed by extensive clinical research.
The newer peptide conversation is much broader.
You may be hearing names like BPC-157 and TB-500 for healing and injury recovery, along with other peptides promoted for muscle growth and body composition, metabolism, energy, cognition, skin health and longevity.
There is legitimate scientific interest in peptides, with researchers studying their potential across a wide range of conditions. The disconnect is that enthusiasm – and access – for some peptides has moved considerably faster than human research.
How are people getting peptides? The Center for Science in the Public Interest recently published a piece on the peptide marketplace, including just how easy these products can be to obtain. Their reporting helps make sense of the marketplace by breaking it into a few broad categories:
There are prescription peptides, prescribed by healthcare providers – whether through traditional medical practices, wellness clinics or telehealth platforms – and often prepared by compounding pharmacies. Compounding has an important role in medicine, allowing pharmacists to customize medications for patients with specific needs. But compounded drugs are not FDA-approved, meaning FDA has not evaluated them for safety, effectiveness and quality before they reach patients in the same way it evaluates an approved drug.
Then there are peptides sold online as “for research use only.” The websites may explicitly state that their products aren’t intended for human use yet still allow us to purchase vials with little more than an acknowledgement of the disclaimer.
And there are international sellers, including manufacturers outside the United States selling directly or through intermediaries. These products may cost substantially less, with less certainty around manufacturing, purity and oversight.
The lines between these categories can also blur. A website can sell a “research” peptide. A telehealth provider can prescribe a compounded one. And having a prescription doesn’t necessarily mean that the particular peptide has been FDA-approved or that we have strong evidence for the reason it’s being prescribed.
What does the research actually show? Both BPC-157 and TB-500 are widely promoted for tissue repair and recovery. Animal and laboratory research offers intriguing reasons to keep studying them. But compelling biology isn’t the same as compelling human evidence. For several of today’s most popular peptides, we still don’t have robust clinical trials telling us about dosage, whether they work or what happens with long-term use.
Safety isn’t only about the peptide itself, either. It’s also about what’s in that vial in the refrigerator. Is it actually the stated compound and dose? Is it pure and sterile? Could it be contaminated – or contain compounds or ingredients that aren’t disclosed on the label?
And the regulatory landscape is changing, too. This summer, an FDA advisory committee considered wider compounding access for several peptides that have gained popularity. That’s significant, but it isn’t the same as FDA approval – and it doesn’t tell us whether these peptides actually deliver on the many claims surrounding them.
None of this means peptide therapies don’t hold promise. But there’s a big difference between promising science and solid human evidence – and right now, not every peptide being marketed to us has both.
If you’re considering a peptide, find out exactly what you’re getting, where it comes from, whether it’s FDA-approved, what human evidence supports it for your specific goal and what we actually know about its risks. And of course, talk with your doctor before injecting yourself with anything that comes in the mail.
Because the word “peptide” alone doesn’t tell us very much. What matters is which peptide, where it came from, what we’re taking it for – and how much science we actually have to back it up.
