The other side: why doctors and patients defend peptides

Why we are publishing this

On this blog we have reported alerts, negative trials and FDA criticism. We want to be transparent in both directions. A regulator criticizing the lack of data on a peptide does not mean peptides do not work, or that the people who use or prescribe them are wrong. It means the formal evidence does not exist yet. Here is the other side of the debate.

Peptides are already front-line medicine

Since insulin, more than 80 peptide drugs have reached the market for diabetes, cancer, osteoporosis, multiple sclerosis, HIV and chronic pain¹. Some of the biggest medical advances of this decade are peptides:

• Semaglutide: in STEP 1, −14.9% body weight at 68 weeks³; in SELECT, with 17,604 adults with cardiovascular disease and overweight without diabetes, 20% less cardiovascular death, heart attack or stroke².
• Tirzepatide: −20.9% body weight in the SURMOUNT-4 lead-in⁴.
• Bremelanotide (PT-141): FDA-approved for acquired, generalized hypoactive sexual desire disorder in premenopausal women⁹.
• Elamipretide (SS-31): accelerated approval in 2025 for Barth syndrome¹⁰.
• Tesamorelin: approved; in a pooled analysis of two phase 3 trials with 806 HIV patients with excess abdominal fat, the treatment effect on visceral adipose tissue was −15.4% vs placebo at 26 weeks¹¹.

What the doctors who voted yes said

At the July 2026 FDA committee, a majority voted to add six of the seven peptides reviewed to the 503A list; emideltide fell short (6 yes, 7 no). The reasons given by several clinicians who voted yes, according to Healio⁵:

• Access: "I think it's about patient access. That's where I'm coming from." And on KPV, for patients "who don't have any options besides what we have available".
• Real demand: "Nobody put a finished product on a shelf. We took a decision that patients are already making…" And: "Our patients want peptides."
• The gray market: "The FDA has zero control over that channel." One voter cited a patient whose "research-grade" product turned out to be laced with MDMA: "That's not protecting the American people."
• An unmet need: for emideltide, "a legitimate role in individualized patient care that FDA products do not fully serve at this time".

The core reasoning is pragmatic: patients already use these peptides. If the regulated route bans them, they buy them on the gray market, with no doctor, no pharmacy and no controls. Allowing them in compounding pharmacies with a prescription, they argue, is less risky than pretending they do not exist⁵⁶.

The patent problem

An argument that rarely makes headlines: according to McDermott's analysis, supporters noted that the simple structure of these peptides and their long history of use make them hard to patent, and without a patent there is no commercial incentive to pay for the phase 3 trials a formal approval requires⁶. Supporters also pointed to "long histories of use by licensed practitioners" and said inclusion would allow "greater regulatory scrutiny and standards to minimize the risks associated with the current gray market"⁶. Seen this way, the lack of large trials does not prove a peptide is useless: it may reflect that no one has a business model to study it.

The preclinical signal is real

Critics are right that human trials are missing. But supporters have a point too: the lab signal is not made up. In the most recent systematic review of BPC-157 (35 preclinical studies and 1 clinical study), the peptide was associated with better functional, structural and biomechanical outcomes in animal models of muscle, tendon, ligament and bone injury¹². Full-length thymosin beta-4 improved severe dry eye in a small phase 2 trial (9 patients)¹³. GHK-Cu was associated with better closure of diabetic ulcers¹⁴. Kisspeptin-54 triggered oocyte maturation in IVF in 60 women at high risk of ovarian hyperstimulation, and none developed moderate, severe or critical hyperstimulation syndrome¹⁵. These are signals that justify more study, not dismissal.

Politics changed too

US Health Secretary Robert F. Kennedy Jr. said publicly: "I'm a big fan of peptides… I've used them myself and with really good effect on a couple of injuries"⁸. In April 2026 the FDA announced it would remove these peptides from its restrictive list and send them to its advisory committee for review; critics doubt that review will be rigorous⁸.