Peptides 101
Peptides are short chains of amino acids — the building blocks of proteins. They are distinct from full proteins in length and structural complexity, and from small-molecule drugs in their mechanism of action and pharmacokinetic profile. Many peptides occur naturally in the body and serve signaling functions.
The body uses peptides extensively in cellular communication — as hormones, neurotransmitters, growth factors, and immune modulators. Research interest in synthetic or isolated peptides focuses on whether exogenous administration can influence biological signaling in measurable ways.
| Category | Description | Example |
|---|---|---|
| Peptide | 2–50 amino acids, specific signaling function | BPC-157, Selank |
| Protein | 50+ amino acids, complex 3D structure | Insulin, growth hormone |
| Hormone | Peptide or steroid; endocrine signaling | GLP-1, testosterone |
| Small-molecule drug | Non-peptide, synthetic chemical compound | Metformin, rapamycin |
Evidence Posture Key
Every compound in the Peptide Library is labeled with an evidence tier. Understanding these tiers is essential to reading the science accurately.
| Tier | What it means | What it does not mean |
|---|---|---|
| In vitro | Effects observed in cell or tissue culture | Does not predict human effects |
| Animal | Effects observed in rodent or other animal models | Does not establish human safety or efficacy |
| Mechanistic | Proposed mechanism based on known biology | Not demonstrated in controlled trials |
| Early human | Small, pilot, or open-label human studies | Not confirmatory; subject to bias |
| Approved drug class | A related FDA-approved drug provides class evidence | Does not validate compounded versions |
| FDA-approved product | This specific formulation is FDA-approved | Approval does not extend to compounded or off-label use |
| Investigational only | No human evidence; research use only | Should not be inferred as safe or effective |
Peptide Categories
Peptides researched in the longevity and regenerative medicine space span a broad range of biological mechanisms. The categories below are educational frameworks — not indications or treatment categories.
- Metabolic / incretin-related — GLP-1, GLP-2, Retatrutide, Cagrilintide
- Mitochondrial / energy signaling — MOTS-C, NAD+ adjacent compounds
- Tissue-response / extracellular matrix — BPC-157, TB-500, GHK-Cu
- Immune / inflammatory signaling — KPV, GHK-Cu, secretome-adjacent
- GH-axis / endocrine signaling — CJC-1295, Ipamorelin, IGF-1 LR3
- Longevity / cellular aging — Epitalon, MOTS-C, Pinealon
- Melanocortin pathway — PT-141, MT-2
- Neurological / cognitive — Semax, Selank, Dihexa
Regulatory Watch
| Concept | Plain-language explanation |
|---|---|
| FDA approval | A specific drug product reviewed and approved by the FDA for defined indications, dosing, and manufacturing. Applies to the approved product only. |
| 503A compounding | Pharmacy-based compounding for individual patient prescriptions. Subject to state board oversight. Cannot copy commercially available approved drugs. |
| 503B outsourcing facilities | Larger-scale compounding facilities registered with the FDA. May produce drugs without patient-specific prescriptions. Subject to cGMP standards. |
| Bulk drug substance lists | FDA-maintained lists of substances that may or may not be used in compounding. Category 1 = under review. Category 2 = FDA recommends against use. |
| PCAC | Pharmacy Compounding Advisory Committee. Reviews nominated bulk substances. Next key review: July 23–24, 2026. |
Peptide Library
A reference library of compounds researched in the longevity and regenerative medicine space. Dosing, reconstitution, and treatment protocols are excluded from public pages and available in the gated clinician layer only.