What are peptides? Inside the ‘biohacker grey market’ of inj…

‘What are peptides?!’ This thought might pop into your head if you take even the quickest scroll through the top beauty trends on TikTok on your nightly doomscroll. While topical peptides like copper and argireline — which can promote collagen, enhance skin firmness and encourage repair — have been in our skincare serums and lotions for years now, a dangerous new trend is rising where people are injecting themselves with peptides that aim to influence everything from shinier, thicker hair to glowing skin — but at a huge risk to their health.

Similar to how GLP-1s like Ozempic and Mounjaro work, these peptides are being injected by those in the pursuit of beauty — but often, the injectables are illegally sourced and even labelled as ‘not safe for human consumption’. They also have ties to biohacking and the far-right-influenced ‘looksmaxxing’ trend. How did we get here? Below, we explain everything you need to know about the injectable peptides.

What are injectable peptides?

There’s often some confusion over the term ‘peptides’, as we see the word all the time on our skincare products at home and in shops. Topical peptides (that is, peptides incorporated into our serums) are largely safe and beneficial for skin — but some injectable peptides, that are unapproved for human use in the UK, are being increasingly used to support beauty goals like better skin and hair, as well as general wellness and longevity. While some peptides have been used to treat medical conditions for more than a century, including insulin, one of the first peptide hormones to be discovered that helps people with Type 1 diabetes and some with Type 2 manage their blood sugar levels, there are many that are unstudied and unregulated for humans to use.

The most commonly used peptide injectables for beauty goals — which often have long-winded, alphanumeric names like BPC-157, GHK-Cu, or TB-500 — are made up of short chains of amino acids that naturally occur in the body, and are administered subcutaneously, usually by injecting fat around the stomach area, to stimulate collagen production, improve elasticity, and promote tissue repair at a deep, cellular level. Often, these injectable peptides are mixed and matched, in what’s known as a ‘stack’, with people clambering to find out what certain influencers’ unique ‘stack’ is, in aims to achieve a similar look. They essentially act as ‘messengers’, instructing the brain to release certain hormones to support certain biological processes, such as increasing collagen production. But this beauty method, which intrudes on your body’s natural processes, is untested in humans — meaning users are essentially guinea pigs for a new and unregulated type of drug.

In the age of biohacking and ‘looksmaxxing’ through wellness trends like supplements, morning sheds and baby Botox, injectable peptides are the latest in a long line of quick hacks that aim to give results almost immediately. But at what cost?

The dangers of using injectable peptides

“Whilst it’s great to see people taking a proactive approach to their health and considering the importance of longevity and positive ageing, the increased use of injectable peptides is very concerning,” shares Dr Ben Taylor-Davies, co-founder of award-winning The Stockbridge Clinic, who is passionate about beauty industry regulation. “Peptides such as GHK-Cu and BPC-157 have no data to support their safety for human use, unlike prescription medicines, which have undergone rigorous clinical trials to establish safety and understand their effects on the human body.

“Research-only peptides carry significant risks, many of which we may not even be aware of in terms of long-term health impact. Until we have clinical research studying the safety and efficacy of these substances for human use, which will likely result in them becoming prescription-only medicines, it is simply not safe to inject these products in the pursuit of health, longevity or beauty,” he says.

In early 2026, regulators in the United States fined a doctor and a pharmacist $10,000 for offering peptide injections at an anti-ageing conference, which left two women who received the injections having to be hospitalised and intubated to help them breathe. There are yet to be any serious cases in the UK, but with the trend sweeping the US — according to a report by The Guardian, workers of the big tech companies in San Francisco are known to enjoy ‘peptide raves’ with partygoers ‘entertained by a lab-coated man demonstrating how to inject liquid peptides’ — it doesn’t seem like it’ll be long until we start seeing the repercussions in the UK, too.