Short answer
Peptides and proteins are made from amino acids linked by peptide bonds. Peptides are generally shorter chains, while proteins are usually larger. There is no single precise length boundary; folding or a manufacturing method does not by itself define the category.
What size and structure tell you
Chemical synthesis and biological production are both used for amino-acid chains; length alone does not determine the production method. One example is chemically synthesised erythropoietin, a protein. Analytical questions are separate: chromatography assesses separated components under its stated method, mass spectrometry can support identity, and quantity needs an appropriate measurement. A purity percentage alone does not establish the amount in a vial.
BPC-157 is fifteen amino acids long. Semaglutide has thirty-one, with modifications studied in its original development work that extend its circulation half-life. Circulation half-life is not a storage instruction. For a laboratory vial, follow the selected material's supplier instructions for its exact form and formulation.
Why names like BPC-157 or retatrutide appear so quickly
Research themes help organise reading, but they do not make different materials interchangeable. BPC-157 has been studied in preclinical tissue-repair models. TB-500 is a trade name associated with thymosin beta-4 or fragment offers; match the material in a paper to the exact supplied compound before applying actin-binding or cell-migration findings. Principal receptor targets distinguish semaglutide (GLP-1), tirzepatide (GIP and GLP-1), and retatrutide (GIP, GLP-1 and glucagon). GHK-Cu is a defined complex of a tripeptide and a copper ion.
The distinction that matters more than the chemistry
Specific peptide-containing preparations are authorised prescription medicines; authorisation applies to the preparation, not every material sold under the same compound name. Our offers are intended for laboratory research. A research-only label does not by itself determine classification, which depends on the product's composition, presentation and function. This page gives no human-use protocol. The framework is set out on legal information, and the Irish specifics on are peptides legal in Ireland.
Legal information
Medicine versus laboratory reagent, what the HPRA oversees, and what a queried parcel is asked for.
Lab reports
The right place to go if you want to compare basic explanations with documents and batch-level testing.
Research summaries
Background page on research themes, terminology, and the wider site context.