What the hell is a peptide.
Short answer: a small chain of amino acids your body uses as a signal. Long answer below.
A is a short chain of amino acids linked together. Anything between 2 amino acids and ~50 is a peptide. Above 50, it's a protein.
Your body makes thousands of peptides naturally. Insulin is a . Oxytocin is a peptide. Glutathione is a tripeptide. The pituitary spends most of its day making peptide hormones that tell other glands what to do.
What we mean when we say "" on this site is a synthetic or semi-synthetic peptide that someone is injecting (or applying topically) for a non-trivial reason — weight loss, recovery, sleep, skin, longevity, libido, cognition. Some are drugs. Some are research-use-only chemicals sold legally for "research" but used by humans anyway. Some are sold by compounding pharmacies with a real prescription.
The catalog covers every meaningful one. The stack builder lets you mix them. The how-to pages explain how to actually use them. We don't sell them. We have no vendor relationships. We just read every study so you don't have to.