What peptides are
A peptide is a short chain of amino acids, the same building blocks that make up proteins. Most peptides in this library are between 2 and 50 amino acids long. Your body makes thousands of them, for example insulin, oxytocin and the gut hormone GLP-1.
Peptide drugs copy or modify these natural signals. Some are tightly tested medicines, such as semaglutide for diabetes and obesity. Others are lab-made fragments that have only been tested in mice and are sold online as “research chemicals”.
A few compounds in the library are not peptides at all, such as MK-677, NAD+ and Urolithin A. We include them because they are often sold or stacked with peptides, and we label them clearly.
How they work in the body
Peptides act like keys. Each one fits a specific receptor and switches on a signal: release growth hormone, slow down the stomach, calm inflammation, darken the skin. That precision is why some peptides work well as medicines.
The same precision has limits. A signal that helps one tissue can push another in the wrong direction. Growth signals do not choose which cells grow, and appetite signals do not only act on appetite. This is why the risk section on every profile gets the same space as the benefits.
How to read the evidence level
Every profile states how well the effects are shown in people. We use four levels:
| Level | What it means |
|---|---|
| Strong | Large human trials. Effects and common side effects are well described, at least for the approved use. |
| Moderate | Some human trials, but smaller, shorter or with mixed results. |
| Limited | Small or low-quality human data. Most claims rest on animal or cell studies, or on personal reports. |
| Animal only or none | No meaningful human data. Effects and safety in people are unknown. |
Two questions help with any claim you read online. First, was it tested in people, or in mice and cells? Second, how many people, for how long, and compared with what? A study of 12 people over four weeks with no control group tells you very little.
How to read the three scores
Each compound gets three separate 1 to 10 scores. They are editorial estimates based on published research, not measured values.
Effect strength
How hard the compound acts on the body when it works.
Proof level
How well that effect is shown in humans.
Risk level
How much can go wrong, including unknowns.
We keep them apart on purpose. The strongest-acting compounds are often the least tested. A single “rating” would hide that trade-off.
Safety basics
Unregulated products
Most “research peptides” sold online have no quality control. Tests of these products often find the wrong amount, impurities or a different compound.
Unknown is not safe
Animal-only data means nobody knows how the compound behaves in people over months or years.
Cancer questions
Growth-factor peptides such as IGF-1 variants, GH secretagogues, BPC-157 and TB-500 carry a theoretical risk of feeding existing cancers.
Medical supervision
Anyone using these compounds regularly needs a doctor and bloodwork, for example IGF-1, glucose and HbA1c, hormones and lipids.
If you compete in a tested sport, check the WADA status on each profile. Many peptides fall under class S0 (substances not approved for human use) or S2 (peptide hormones and growth factors).
Approval and the law
“Approved” means a regulator such as the FDA or EMA reviewed trial data for a specific use. Using an approved drug for a different goal is “off-label” and was not part of that review.
In 2023 the FDA placed several popular peptides, including BPC-157, ipamorelin and CJC-1295, on its list of bulk substances with significant safety concerns for compounding. Rules differ by country and change often. Each profile shows the status we found up to mid-2026; check current sources before relying on it.
Why viral results are not proof
Many people first hear about peptides from a video where one person runs a multi-month “protocol” and reports great results. These stories are interesting, but they cannot tell you whether a compound works. Common problems:
- No bloodwork or measurements are shown, only photos, a wearable score and how the person feels.
- Ten or more things change at once, so no result can be tied to any single compound.
- Other factors explain the change, such as testosterone therapy, a strict diet or more training.
- There is no comparison group and no follow-up, so placebo effects and normal ups and downs look like progress.
We do not publish doses, stacks or protocols. If a compound interests you, take the profile to a qualified professional and talk it through.