Care with Roscoe Nelson, MD, board-certified urologist.
What a peptide is
A short chain of amino acids. Your body runs on them: insulin is one, so is the hormone your hypothalamus releases every night to trigger growth hormone. Semaglutide and tirzepatide are peptides. So is PT-141, which I use for low desire. The category itself is ordinary. Most of what gets marketed under the name is not.
Why so few carry FDA approval
Usually not because they failed. Most are molecules the body already makes, so nobody can patent them, so nobody pays for the trials that approval requires. That gap is real, and it is where the hype lives. Compounded peptides are not reviewed the way approved drugs are, and the rules on what can be compounded change often enough that availability is a moving target.
The five questions
Before I prescribe any peptide it has to clear all five.
- Is there a mechanism I believe?
- Has it shown a benefit in placebo-controlled trials in people?
- Do we understand the safety, the dosing and what to monitor over time?
- Does the benefit justify the risk?
- Is there a better-studied way to get the same result?
Most of what is sold as peptide therapy fails the second question. The fifth eliminates most of the rest.
What I prescribe
That does not mean I avoid them. I prescribe several peptides today where the evidence and the regulatory standing hold up: the GLP-1 medications, and NAD+ and sermorelin among others. Bring me the one you are curious about, with the product name and why you want it, and we will run it through the five questions together. Asking does not commit you to anything, and I will not write for something that fails the test. Dosing belongs in the room with your history in front of me, never on a web page.
Whatever earns a place sits on top of the four things that carry most of the proven benefit for a long, healthy life: exercise, a diet that keeps you lean, real sleep and lower stress. Peptides that work make those easier. They do not replace them.