Peptides in the UK: the honest guide
What peptides are, which ones people mean, what is legal, what is safe, how they are taken and stored, and how to buy without being fooled. Written by a UK company that makes two of them and sells none of the rest.
Start here
A peptide is a short chain of amino acids. The word now covers prescription weight-loss injections, research vials sold "not for human use", nootropic nasal sprays, and collagen powder, and the rules, risks and evidence for each are completely different. What are peptides? sorts the categories.
The law
Four tiers: licensed medicines (semaglutide, tirzepatide) on prescription only; unlicensed research peptides (BPC-157, TB-500, GHK-Cu, ipamorelin) legal to buy and possess; nootropic peptides (Semax, Selank) sold as supplements; and a short controlled list around growth hormone. Are peptides legal in the UK? has the table. Sport has its own list; most research peptides are WADA-banned.
Safety
Decided by the molecule, the source and the dose, in that order. The commonest harm in the UK is counterfeit GLP-1 pens and un-assayed research vials, not the peptides themselves. Are peptides safe? gives the side effects by category and a five-point check.
The peptides people search for
Semaglutide, tirzepatide and retatrutide (weight loss; prescription-only or unlicensed). BPC-157 (tissue repair; animal data, no human trials). GHK-Cu (skin; good topical evidence, none injected). Semax (attention and memory; one human study, decades of use). Selank (stress and composure). We make the last two as finished nasal sprays and do not sell the others.
Buying, reconstituting, dosing, storing
Research peptides in the UK explains what a certificate of analysis should show and six questions for any vendor. How to reconstitute peptides covers bacteriostatic water and technique; the peptide calculator turns vial size, water and dose into syringe units or spray counts; peptide storage covers the fridge rules. Oral, nasal or injectable explains why the route matters. Peptide therapy in the UK separates regulated clinics from vial resellers.
Our position
COGENT exists because the UK peptide market sold powder with no testing and left buyers to work out the rest. We make Semax and Selank as assayed, preserved, metered sprays with the batch certificate published, and we write about the rest of the field honestly because the people searching for it deserve better than a vendor forum. If that standard can be met for another peptide in future, we will make it. If it cannot, we will not.
Peptides in the UK
Most are legal to possess. Licensed peptide medicines such as semaglutide need a prescription; research peptides such as BPC-157 are legal to buy but sold "not for human use"; nootropic peptides Semax and Selank are sold as supplements; a few growth-hormone compounds are controlled. Full guide.
Licensed peptide medicines from a pharmacy with a prescription. Research peptides from UK vendors selling vials "for research"; quality varies and a batch certificate is the minimum. Finished nootropic peptide sprays from COGENT (Semax now, Selank soon).
It depends on the peptide, the source and the dose. Licensed medicines have known profiles; research peptides mostly have animal data only; the commonest real-world harm is counterfeit or contaminated product. Safety guide.
Semax is the only peptide with a controlled human study in healthy adults showing improved attention and memory across a working day. It is taken as a nasal spray. Semax guide.
Concentration is the vial amount divided by the water added; the dose is then a volume of that solution. Our peptide calculator gives syringe units or spray counts from the numbers on your vial.
Powder: fridge or freezer. Reconstituted: fridge, use within weeks. Finished preserved sprays: room temperature in use. Storage guide.
Yes to buy and possess; it is unlicensed and sold as a research chemical, and it is banned in tested sport. BPC-157 in the UK.
It has no licence anywhere, so it is legal to possess but every UK sale is of an unlicensed, untested product. Semaglutide and tirzepatide are prescription-only. GLP-1 peptides in the UK.
Every peptide guide
What are peptides? Hormones, medicines, research vials and nootropics
Short chains of amino acids, and a word that now covers five different markets. The categories, what each does, and how they are taken.
Are peptides legal in the UK? The four categories explained
Prescription GLP-1s, research peptides sold 'not for human use', nootropic peptides sold as supplements, and the few that are controlled.
Are peptides safe? Side effects by category
Why the answer depends on the molecule, the source and the dose, and a five-point check before using any of them.
Research peptides in the UK: what 'not for human use' means
How the vial market works, how to read a certificate of analysis, and six questions for any supplier.
How to reconstitute peptides (and where to buy bacteriostatic water in the UK)
Water type, the method step by step, making a nasal spray, and the mistakes that waste a vial.
How to store peptides: powder, solution and finished sprays
Fridge or freezer, for how long, the signs of degradation, and travelling with them.
BPC-157 in the UK: evidence, legal status and why we don't sell it
The most searched research peptide: extensive animal data, almost no human trials, legal to possess, banned in sport.
GHK-Cu in the UK: the copper peptide with evidence on skin and none injected
What it is, the topical trials, the injectable claims, and its legal status.
GLP-1 peptides in the UK: semaglutide, tirzepatide and retatrutide
Prescription-only where licensed, unlicensed where not, and the most counterfeited medicines in the country.
Oral, nasal or injectable: how peptides get into the body
Why most are injected, why Semax and Selank are sprays, which few survive the gut, and a table by peptide.
Peptide therapy in the UK: regulated clinics vs vial resellers
How to tell licensed prescribing from research vials with a consultation fee, and the questions to ask.
Peptide nasal sprays explained: why peptides go up the nose
Why a capsule would not work, how the nasal route reaches the brain, and what a good peptide spray needs.