- Peptides are short chains of amino acids that signal specific actions in the body.
- Evidence varies widely. Some peptides are FDA-approved drugs; others have mostly animal data.
- Safe peptide therapy starts with labs, a physician review and ongoing monitoring.
Peptides are everywhere online, promising better recovery, sleep, skin and body composition. Some of that is backed by solid research. Some isn't. Here are straight answers to the questions people ask most.
Insyght physicians review 100+ biomarkers before recommending any peptide, then track how your body responds.
What exactly is a peptide?
A peptide is a short chain of amino acids, the same building blocks as protein. Your body makes thousands of them. Insulin and GLP-1 are peptides. Peptide therapies use natural or lab-made versions to send a targeted signal, like "release growth hormone" or "reduce appetite."
Which peptides are most common?
| Peptide | Main use people seek | How it's given | FDA status |
|---|---|---|---|
| Semaglutide / tirzepatide | Weight loss, blood sugar | Weekly injection | FDA-approved |
| PT-141 (bremelanotide) | Low sexual desire | Injection as needed | FDA-approved for a specific use in women |
| CJC-1295 + Ipamorelin | Growth hormone support, sleep, recovery | Injection | Not FDA-approved |
| BPC-157 | Tissue and gut repair | Injection or oral | Not FDA-approved |
| Thymosin alpha-1 | Immune support | Injection | Not FDA-approved in the US |
How strong is the evidence?
| Peptide | Best evidence so far |
|---|---|
| Semaglutide / tirzepatide | Large randomized trials in humans |
| PT-141 | Randomized trials in humans |
| CJC-1295 / Ipamorelin | Small human studies |
| BPC-157 | Mostly animal studies |
| Thymosin alpha-1 | Human trials, mainly outside the US |
Are peptides legal?
FDA-approved peptides are legal with a prescription. Rules for compounded peptides have changed several times, and the FDA has restricted some, including BPC-157, from standard compounding. A physician should only prescribe peptides that can be sourced legally from a licensed pharmacy.
What are the side effects?
They depend on the peptide. Common ones include injection-site redness, nausea, flushing, water retention and changes in blood sugar. Growth hormone peptides can raise IGF-1 and glucose. That's why labs before and during therapy matter.
How does physician-guided peptide therapy work at Insyght?
- Test: one blood draw measures 100+ biomarkers.
- Review: a physician reads your results and goals.
- Plan: if a peptide fits, you get a clear dose, schedule and expected timeline.
- Monitor: follow-up labs show whether it's working and staying safe.
Peptide myths vs. facts
| Myth | Fact |
|---|---|
| "Peptides are natural, so they're safe." | Natural doesn't mean risk-free. Dose, source and your health all matter. |
| "Research peptides online are the same thing." | "Research use only" products aren't made for people and can be mislabeled or contaminated. |
| "You'll feel results in days." | Most peptides take weeks to months to show clear effects. |
| "One peptide works for everyone." | The right choice depends on your labs, goals and history. |
Frequently asked questions
How long do peptides take to work?
Do I need bloodwork before peptide therapy?
Are oral peptides as good as injections?
Insyght combines a 100+ biomarker panel with physician review, so any peptide plan is built on your own results. $199 a year.
Keep reading
How we read 100+ biomarkers against optimal, not just the population average.
The panelWhat we testEvery biomarker in the Insyght Core Panel, across 10 body systems.
60 secondsThe Baseline CheckEight questions to see which of your systems deserves a closer look.
