In 2026 peptides are firmly in the spotlight — you come across them in skincare, in the news about weight-loss research and in sports science. Yet the word “peptide” covers three completely different things, and online that information easily gets tangled. In this guide we explain clearly and with sources exactly what peptides are, which types exist and within what framework research peptides are studied.
Peptides are short chains of amino acids (typically 2–50), linked by peptide bonds — shorter than proteins. In research, research peptides such as BPC-157 and Retatrutide are studied for mechanisms around tissue and metabolism. At Peptide Lab every batch is lab-verified at ≥99% purity with a Janoshik certificate. For research purposes only.
What is a peptide?
A peptide is a short chain of amino acids linked to one another by so-called peptide bonds. Amino acids are the molecular building blocks of all life; when two or more amino acids are joined together, a peptide is formed. A peptide bond is a covalent amide bond that forms between the carboxyl group of one amino acid and the amino group of the next, releasing a water molecule.
Depending on the number of amino acids, biochemists use different terms: a dipeptide consists of two amino acids, a tripeptide of three, and longer chains are called oligopeptides or polypeptides. The order of the amino acids — the sequence — determines the properties of the peptide. It is precisely that exact sequence that makes peptides interesting as a subject of scientific research.
What is the difference between peptides, proteins and amino acids?
The distinction comes down to chain length: amino acids are the individual building blocks, peptides are short chains and proteins are long, folded chains. A handy rule of thumb: one amino acid is a single building block, a peptide consists of roughly 2 to 50 amino acids, and once a chain becomes longer than about 50 amino acids we generally speak of a protein. The boundary is not sharply defined; it is a gradual transition drawn in the literature at around ~50 amino acids.
Besides length, structure also plays a role. Proteins fold into complex three-dimensional shapes that determine their function. Peptides are shorter and more flexible, which makes them more precisely synthesisable and characterisable in research.
Illustrative. The boundary between peptide and protein sits around ~50 amino acids.
What types of peptides are there?
Broadly there are three categories: endogenous (natural) peptides, cosmetic peptides and synthetic research peptides. Endogenous peptides occur naturally and perform signalling functions — think of certain hormones. Cosmetic peptides are found in skincare products. And research peptides are synthetically produced peptides used exclusively for scientific research.
Within the research field, research peptides are usually organised by the domain in which they are studied. The overview below gives a summary — and links straight through to the relevant research category in our catalogue:
What do peptides do in scientific research?
In research, research peptides are studied for biological mechanisms such as tissue processes, metabolism and cellular signalling — strictly within a research context. It is important to emphasise that this is about research: research peptides are not medicines and no health claims are attached to them. Scientific interest focuses on different themes per peptide.
- Recovery & tissue: peptides such as BPC-157 and TB-500 are studied in preclinical research in relation to tissue and repair processes.
- Metabolism: compounds such as Retatrutide and MOTS-C are the subject of research into metabolism and energy balance.
- Growth-hormone research: CJC-1295 and Ipamorelin are studied as growth-hormone secretagogues in sports-science research.
- Ageing & longevity: Epithalon, NAD+ and SS-31 feature in research into cellular ageing.
Want to see the background and the associated peptides per research domain? Then browse our full catalogue of research peptides or dive into how we verify purity and quality.
Cosmetic peptides versus research peptides
Cosmetic peptides in creams and serums and injectable research peptides are fundamentally different products — even though the search term shares the same name. Many search results about “peptides” are about skincare: copper peptides, matrixyl and similar ingredients applied topically to the skin. That is a cosmetic application with its own legal framework.
Research peptides, by contrast, are lyophilised (freeze-dried) powders that, after reconstitution, are used exclusively for laboratory and research purposes. They are not marketed as a cosmetic product and not as a medicine. Confusing these two categories is the most common mistake online — and precisely why a clear, separate explanation matters.
How is the purity of research peptides determined?
The purity and identity of research peptides are determined with analytical techniques such as HPLC and mass spectrometry. HPLC (High-Performance Liquid Chromatography) separates the components of a sample and reveals what percentage is actually the intended peptide. Mass spectrometry (MS) then confirms the molecular identity and the exact molecular weight.
At Peptide Lab we apply a threshold of ≥99% purity and have every batch independently tested by Janoshik Analytical. The accompanying Certificate of Analysis (COA) is publicly viewable per batch, linked to the lot number on the label. That way you can trace exactly what you have in hand.
Want to know more about how to read a certificate? See our public batch lab certificates.
Are peptides safe and legal?
Research peptides are offered exclusively for laboratory and research purposes — not for human or animal consumption and not as a medicine. In public debate, peptides are sometimes portrayed as “dangerous” or as a hype. That framing often arises because research products are confused with consumer use. Within the correct framework the core is simple: research peptides are research material.
In this context, safety mainly means purity, correct laboratory handling and transparent documentation — not a dose or usage advice. Points of attention such as sterility, reconstitution with bacteriostatic water and proper storage are part of responsible research.
This information is general and intended solely for a research context. Peptide Lab supplies research peptides exclusively for laboratory and research purposes. Not for human or animal consumption, not a medicine and not medical or legal advice.
Buying peptides for research: what to look out for
When selecting a supplier, look at four things: verified purity, a public COA, batch traceability and reliable EU shipping. The quality of research material stands or falls with transparency. A supplier that publishes an independent certificate per batch and links the lot number on the label to that certificate makes reproducible research possible.
- Purity: ≥99%, determined by HPLC and confirmed by mass spectrometry.
- COA: public and batch-specific, from an independent lab such as Janoshik.
- Traceability: lot number on the label, traceable to the certificate.
- Delivery: fast, discreet EU shipping with correct packaging.
See how we implement this on the science page, or go straight to the shop with all research peptides.
Frequently asked questions about peptides
What are peptides in short?
Peptides are short chains of amino acids linked together by peptide bonds. They are shorter than proteins — typically 2 to 50 amino acids. In scientific research, so-called research peptides are studied for a wide range of biological mechanisms.
What is the difference between a peptide and a protein?
The difference is mainly chain length. Amino acids are the building blocks, peptides are short chains (2–50 amino acids) and proteins are long, folded chains of usually 50 or more amino acids. The dividing line is not exact and is drawn in the literature at around ~50 amino acids.
What types of research peptides are there?
Research peptides are often classified by the research domain in which they are studied: recovery (such as BPC-157 and TB-500), metabolism (such as Retatrutide and MOTS-C), growth-hormone research (such as CJC-1295 and Ipamorelin) and longevity (such as Epithalon and NAD+).
Are peptides the same as the peptides in skincare?
No. Cosmetic peptides in creams and serums (such as copper peptides) are formulated for topical, cosmetic use. Research peptides are lyophilised powders offered exclusively for laboratory and research purposes. They are fundamentally different products.
Are peptides safe?
Research peptides are offered exclusively for laboratory and research purposes and are not intended for human or animal consumption. In this context, safety is a matter of purity, correct handling and transparent documentation — not usage advice. Peptide Lab publishes an independent Janoshik certificate for every batch.
Are peptides legal?
Research peptides are offered within a research-only framework: for research purposes only, not as a medicine and not for consumption. They therefore fall outside regular medicinal use. This is general information and not legal advice.
Sources & further reading
Independent third-party references — for further reading, not an endorsement or partnership.
- Dr. William Seeds, MD — Peptide Protocols — Medical references on peptides in cellular medicine (SSRP Institute)
- Dr. Peter Attia, MD — Scientific analyses of longevity and a critical view of peptide and hormone hype
