A physician explainer published by Hartford Hospital argues that "peptide therapy" has become a marketing category rather than a single treatment, covering products with wildly different levels of evidence behind them. Joe Li, DO, of Hartford HealthCare Medical Group says not every product sold under the label comes with the same research or oversight.

Peptides are chains the body makes naturally to help systems communicate, involved in appetite, blood sugar, growth and metabolism. Li describes peptide medications as designed to copy or influence signals that already exist in the body, which he says can make them useful for certain conditions without making every marketed product safe or effective.

The approved end of the shelf

Peptide-based drugs are not new to medicine. Insulin is the familiar example, and Li points to GLP-1 medications such as semaglutide and tirzepatide as the more recent ones, both working by mimicking or activating naturally occurring peptide signals.

The distinction the piece keeps returning to is a good one. FDA approval attaches to a specific medication for a specific use, so an injection described as peptide therapy has not necessarily been through anything resembling that process.

What the clinics are selling instead

Wellness clinics and online sellers advertise peptide injections for slow workout recovery, poor sleep and changes in body composition. BPC-157 turns up marketed for tendon, ligament and muscle injuries, while ipamorelin and CJC-1295 are promoted for growth hormone, muscle and signs of aging.

None of those uses, Li says, have been supported by the level of human research an FDA approval requires. Much of the available research on the wellness peptides was done in labs or animals, and he says strong human studies are what tell you whether a treatment offers meaningful benefit and to whom.

The stacking problem

Some clinics recommend combining several peptides, a practice the article calls peptide stacking. That adds uncertainty on top of uncertainty, because the combination may have no established dose or safety record at all.

Li also raises what is physically in the vial. Compounded drugs are not FDA-approved, and he notes that poor compounding can produce contamination or incorrect amounts of active ingredient, an assurance you do not get buying from an unregulated website.

Bottom line

Li's advice to patients is to describe the symptom to a doctor before picking a product, since fatigue and slow recovery have many causes. The open question the piece leaves is not whether peptides do anything, insulin settles that, but how much of the wellness catalog will ever be tested in people.