Where the confusion comes in

BPC-157, sometimes nicknamed the ‘wolverine peptide’, is promoted as a healer for tendons, ligaments, the gut lining and general inflammation. However, the evidence for it comes overwhelmingly from animal studies rather than robust human trials. In late 2023, the US Food and Drug Administration (FDA) placed BPC-157 in a category of compounding substances considered to carry significant safety risks, citing concerns including the potential to trigger an immune response. The FDA continues to issue warning letters to online sellers.

CJC-1295 and ipamorelin, often sold together as a ‘stack’, are growth hormone secretagogues (GHS): substances that tell the pituitary gland to release more growth hormone. In the UK, neither CJC-1295 nor ipamorelin hold marketing authorisations from the Medicines and Healthcare products Regulatory Agency (MHRA). They are not approved for any medical condition, cannot be prescribed by UK doctors, and are not available via the NHS. For otherwise healthy adults chasing fat loss, muscle gain or better sleep, the long-term safety and efficacy data simply do not exist yet.

Melanotan II, dubbed the ‘Barbie drug’ or ‘vacation peptide’, is injected or sniffed as a nasal spray to darken the skin without sun exposure. It works by mimicking a hormone that stimulates melanin production in the body, but that same mechanism can darken or increase existing moles, making early skin cancers harder to spot. It has been linked to nausea, flushing and, in rarer cases, priapism (a prolonged, often painful erection that lasts for hours). Regulators in the UK and elsewhere have repeatedly warned that it is illegal to sell Melanotan II without a prescription.

GHK-Cu, a copper-binding peptide, has some evidence for efficacy. Applied topically, a few clinical trials have shown that it can modestly improve skin firmness, density and fine lines, and dermatologists consider the underlying science to be credible. The problem is the leap that some sellers now make from a well-tolerated skincare ingredient to an injectable, systemic anti-ageing or weight loss product, for which there is no human trial evidence.