What peptides are
Amino acids are the building blocks. When amino acids link together, they form peptide bonds. Short chains are commonly called peptides, while longer folded chains are usually called proteins. The line is not the whole story, because biological activity depends on structure, receptor binding, dose, route, and context.
Your body makes many endogenous peptides. Some act like hormones, some help transmit signals, and some participate in immune, metabolic, or nervous system processes. Medical and research peptides are designed to mimic, modify, or study those signals.
A peptide is just a short chain of amino acids. "Peptide therapy" is many different categories, doing many different things.
Why the category gets confusing
The word peptide appears in skin care, nutrition, bodybuilding, endocrinology, and drug development. Collagen peptides in a protein powder are not the same thing as a prescribed injectable peptide. A peptide listed on a vial from an online vendor is not automatically a medication. A compounded peptide is also not the same as an FDA-approved drug product.
Terms worth knowing
- Receptor: a cellular target that a peptide may bind to and activate or block.
- Half-life: how long it takes for the amount of a compound in the body to fall by about half.
- Bioavailability: how much of a compound reaches circulation in active form.
- Stability: whether a compound keeps its strength, quality, and purity under labeled storage conditions.
- Compounded medication: a patient-specific preparation made by a pharmacy when clinically appropriate.
What this means for patients
If you are researching peptide therapy, the safest starting point is not a list of popular compounds. It is a provider conversation about your goal, health history, contraindications, and whether a prescription therapy makes sense. From there, read about online peptide therapy, sourcing and ordering, and results timelines.
Sources