The most-researched peptides of 2026, ranked by evidence

Twelve peptides people ask about most, sorted by how much human evidence stands behind them, from approved drugs down to compounds with almost no human data.

"Peptide" covers everything from Ozempic to vials sold online with a "not for human use" label. Those products don't have the same quality of evidence behind them. This list ranks a dozen of the most-discussed peptides on MyPeps by one question: how much good human evidence is there?

How our 1–5 evidence scale works

Every peptide page on MyPeps has an evidence score. Here is roughly what each level means:

5: Approved, with large trials. Regulators approved it after big randomized controlled trials (RCTs), in which people are randomly given the drug or a placebo.
4: Strong human trials. Large or multiple RCTs exist. It is either not yet approved, approved outside the US, or approved only for a narrow use.
3: Some human data. Small or older human trials, or bigger trials with mixed or negative results.
2: Mostly animal data. Most of the evidence is from animal or cell studies, with tiny or uncontrolled human reports at most.
1: Little or none. Almost no published research, or only lab studies.

The score measures how much is known, not whether something works or is safe. A level-5 drug still has real side effects, and a research vial of an approved molecule is not the approved product.

Level 5: approved drugs with large trial programs

1. Semaglutide (Ozempic, Wegovy). Probably the best-studied peptide on this list. In the STEP-1 trial, people lost about 15% of their body weight over 68 weeks on 2.4 mg. The SELECT trial, with more than 17,000 people, found a 20% lower risk of major heart events in adults with heart disease and overweight.

2. Tirzepatide (Mounjaro, Zepbound). Approved after the large SURPASS and SURMOUNT programs. In SURMOUNT-1, the top dose produced about 21% weight loss at 72 weeks. In SURMOUNT-5, a head-to-head trial, tirzepatide beat semaglutide: 20.2% versus 13.7% weight loss.

3. Tesamorelin (Egrifta). The FDA approved it in 2010 to reduce excess belly fat in people with HIV-related lipodystrophy. That was based on two phase 3 trials with 816 people, in which abdominal fat fell by about 15–17% compared with placebo. Evidence for other uses, such as general fat loss or anti-aging, is much thinner.

Level 4: strong human trials, but limited or no approval

4. Retatrutide. Not approved anywhere yet, but it has a large phase 2 trial and several positive phase 3 trials (the TRIUMPH program). People in those trials lost up to 28.3% of their body weight at 80 weeks. Lilly plans to file with the FDA in early 2027. Long-term safety data is still being collected.

5. Cagrilintide. A long-acting version of amylin, a hormone that helps signal fullness. In the phase 3 REDEFINE 1 trial, cagrilintide alone produced about 11.5% weight loss at 68 weeks. Combined with semaglutide (as CagriSema) it reached 20.4%, or 22.7% among people who stayed on treatment. It is not approved on its own.

6. PT-141 (bremelanotide). The FDA approved it in 2019 as Vyleesi, for low sexual desire in premenopausal women. That was based on two 24-week trials with 1,247 women. The effect was modest. We rate it 4 rather than 5 because the approval is narrow and the data in men is much smaller.

7. Thymosin alpha-1. Approved in a number of countries outside the US (as Zadaxin), with several RCTs in hepatitis and sepsis. The results are mixed. A large phase 3 sepsis trial in China with 1,106 adults found no difference in 28-day death rates compared with placebo.

Level 3: some human data

8. GHK-Cu. A copper peptide with several small human studies, mostly of skin creams and cosmetics. Data on injecting it comes mainly from animal and lab studies.

9. AOD-9604. A fragment of growth hormone that was developed as an obesity drug. It was tested in hundreds of people and seemed well tolerated. However, its largest trial, a 24-week phase 2b study in 536 people, found no meaningful weight loss compared with placebo, and development stopped in 2007. It shows that "tested in humans" and "works in humans" are not the same thing.

Level 2: mostly animal data

10. BPC-157. Well over a hundred animal studies, mostly from one research group, report faster tissue healing. In its 2026 review, the FDA counted five small clinical studies with a few dozen people in total, mostly without placebo groups. The FDA said there is not enough safety information to describe its safety profile. It is banned by WADA. Our BPC-157 page has the details.

11. TB-500. TB-500 is a short fragment of thymosin beta-4. The full-length protein has had some early human trials, for example in eye and wound healing. The fragment sold as TB-500 has mostly animal and anecdotal support. It is also banned in sport.

Level 1: little or no human research

12. IGF-1 LR3. Made as a lab reagent for growing cells. We know of no human clinical trials of this modified form. The human data people sometimes quote is for mecasermin, a different, approved form of IGF-1.

What the ranking does and doesn't tell you

The molecule is not the product. Semaglutide's level-5 evidence comes from Novo Nordisk's manufactured drug. An unregulated vial of "semaglutide" or "retatrutide" was never tested in those trials.
Approval is for specific uses. Tesamorelin's approval covers fat linked to HIV lipodystrophy, not general weight loss.
Low scores mean unknown, not proven harmful. They also don't mean safe. With level-2 peptides, nobody has measured the risks properly in people.

You can sort every peptide on MyPeps by evidence level from the main peptide list. Each peptide page also tags every claimed benefit as human, animal, lab or anecdotal.

This is educational information, not medical advice.