What Are Peptides? A Complete Guide for South African Researchers

"Peptides" gets used as a catch-all term covering everything from skincare ingredients to injectable metabolic research compounds, which makes it a confusing starting point if you're new to the space. Here's the grounding you need before any of the specific comparisons make sense.

What a peptide actually is

A peptide is a short chain of amino acids linked together by peptide bonds — the same chemical bond that links amino acids in any protein. The distinction is purely one of length: chains of roughly 2 to 50 amino acids are generally called peptides, while longer, more complex folded chains are called proteins. A dipeptide has 2 amino acids, a tripeptide has 3 (KPV, discussed elsewhere on our blog, is a tripeptide), and so on up to the oligopeptide and polypeptide range.

This size matters practically. Small peptides are simple enough to synthesize precisely and study for a specific, targeted biological signal, whereas full proteins are structurally complex and much harder to characterize or manufacture consistently. That's a large part of why peptides specifically — rather than full proteins — dominate this research field.

The main research categories

Research peptides broadly cluster into a handful of categories based on what they're studied for:

• Metabolic / GLP-1 family — GLP-1, GIP, and glucagon receptor agonists studied for appetite regulation and glucose metabolism. See our Retatrutide vs. Tirzepatide comparison and Tirzepatide vs. Semaglutide comparison.
• Healing & recovery — compounds like BPC-157 and TB-500, studied for tissue repair. See our BPC-157 in South Africa guide.
• Growth hormone axis — GHRH analogs and secretagogues like Tesamorelin and CJC-1295/Ipamorelin.
• Cognitive & neuroprotective — Semax, Selank, and related compounds. See our brain peptides research overview.
• Mitochondrial & longevity — MOTS-C and related mitochondrial-derived peptides. See our MOTS-C research overview.
• Skin & cosmetic — copper peptides like GHK-Cu, studied for collagen synthesis and wound healing.

How peptides are typically administered

Most injectable research peptides arrive as a lyophilised (freeze-dried) powder that needs reconstituting with bacteriostatic water before use — we cover exactly how long a vial stays good before and after that step in our peptide vial shelf life guide. Some smaller peptides are dosed intranasally instead, which uses a completely different absorption route — see our brain peptides piece for how that works.

Legality and sourcing in South Africa

Research peptides are not registered finished medicines under the Medicines and Related Substances Act, and are sold for research purposes. Accessing them for actual use in South Africa generally happens through one of two routes: a GP-supervised compounding pathway, or direct purchase for research use. Whichever route you take, the sourcing floor should be the same regardless of compound:

1. Third-party HPLC purity testing, ideally ≥99%
2. A lot-matched Certificate of Analysis (COA) — not a generic one that doesn't correspond to your actual vial
3. Cold-chain shipping for lyophilised vials
4. Clear, accurate labelling — no vague or unverifiable claims

Where to go from here

If you already know which category you're researching, our comparison and deep-dive articles above are the faster path in. If you're still getting oriented, our Research Hub has the full peptide database, dosing calculators, and citation library, and our shop lists everything currently available with full purity documentation.