There is no single universal “WhichPeps classification of science”. These labels help readers see what kind of entity they are looking at and prevent adjacent compounds from being mislabelled as peptides.
Peptide
A chain of amino-acid residues linked by peptide bonds. The evidence may range from basic laboratory biology to established medicine depending on the entity.
Peptide analogue / modified peptide
A peptide-like molecule intentionally modified from a reference/native peptide to change properties such as stability, target activity or exposure.
Peptide hormone / hormone analogue
A peptide involved in endocrine signalling, or an analogue designed around a hormone pathway.
Protein / growth-factor-related biologic
A larger protein/biologic or growth-factor-related entity that belongs in the research ecosystem but should not be casually called a peptide.
Small molecule
A lower-molecular-weight chemical compound that may be researched alongside peptides but is structurally not a peptide.
Metabolite / cofactor
An endogenous metabolic molecule or cofactor that can appear in longevity/metabolic discussions without being a peptide.
Other research compound
Mixtures, blends or adjacent entities that need an explicit classification rather than being forced into a peptide label.
Why WhichPeps keeps them together
Real users search by goals, brand names, online nicknames and communities rather than perfect biochemical categories. Discovery can therefore span related entities while the canonical profile preserves scientific identity.
Examples from the current library
| Entity | Type | Why the label matters |
|---|---|---|
| BPC-157 | Peptide | Evidence is mainly preclinical; “peptide” does not imply clinical efficacy. |
| Semaglutide (injectable) | Peptide analogue | Approved evidence is product/formulation/indication specific. |
| 5-Amino-1MQ | Small molecule | It is frequently discussed in the same market but is not a peptide. |
| NAD+ | Metabolite/cofactor | Biochemical relevance does not make it a peptide. |
| GHK-Cu + BPC-157 + TB-500 blend | Mixture/blend | Component evidence does not establish efficacy or safety of the blend as a combined product. |