Counterfeit medicines are most commonly distributed through on-line pharmacies, most of which are hosted outside of the UK. The WHO estimates that up to 50% of medicines sourced from websites that conceal their physical address are counterfeit. This is known as the unregulated supply chain. It should be clearly understood that there are no guarantees of the safety, quality or efficacy of medicines purchased in this way. Many of these websites are advertising and supplying the medicines illegally, with inadequate consultation, no prescriptions and often no involvement of qualified healthcare professionals.

Counterfeit medicines are less frequently, but perhaps more worryingly, discovered in the regulated supply chain, that is through licensed wholesalers, parallel traders and pharmacies. Incidents have steadily increased since 2004, with counterfeit medicine reaching patients on 9 occasions necessitating batch recalls, and discovered at wholesale level on a further 5 occasions. Despite the relatively few occasions when this has occurred, when compared to the enormous scale of the UK market, any incident of a counterfeit medicine being supplied unwittingly to a member of the public by a pharmacist is dangerous and unacceptable.