Peptides and proteins
Both are made from amino acids. Peptides are generally shorter chains, while proteins are longer and often fold into more complex structures. The boundary is useful but not perfectly fixed across every scientific context.
What peptides do in the body
Naturally occurring peptides can carry signals between cells, influence receptors or contribute to biological structures. Their effects depend on sequence, shape, stability, route of exposure and the receptor or pathway involved.
Peptide does not mean approved medicine
A peptide may be naturally occurring, synthetically manufactured, an approved medicine, an investigational drug or an unverified commercial product. These categories must not be treated as interchangeable.
The useful question
Instead of asking whether something is a peptide, ask what evidence exists in humans, whether a regulator has approved a specific product and use, what safety information is known, and what remains uncertain.