Exclusive: Guardian investigation finds several clinics making potentially unlawful claims about benefits of unregulated therapies

• What are peptides, are they safe and is there evidence to back up the hype?

The medicines regulator is investigating whether UK clinics are breaking the law by making claims about the benefits of unregulated, experimental peptide therapies, the Guardian can reveal.

Interest in experimental peptides has boomed in recent years. The substances are delivered by injection and are touted by sellers, influencers and even some medics as aiding everything from anti-ageing to recovery from injury.