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Encyclopedia entry

MHRA medicines classification

The Medicines and Healthcare products Regulatory Agency (MHRA) classifies licensed UK medicines into three tiers, set out in the Human Medicines Regulations 2012. The classification determines who can prescribe or sell the medicine, where the supply can happen, and what advertising is permitted.

The three tiers

Reclassification

MHRA can reclassify a medicine downward (POM to P, P to GSL) when sufficient real-world safety data has accumulated. Orlistat moved from POM to P in 2009. No GLP-1 weight-management medication has been reclassified, and current MHRA position is that the risk profile (pancreatitis, gallbladder events, hypoglycaemia in diabetics) does not support P-tier supply.

What sits outside the tiers

Food supplements (collagen, vitamins, minerals) are regulated by the Food Standards Agency (FSA), not the MHRA. Cosmetic products (peptide serums) are regulated under the UK Cosmetics Regulation 2013. Research peptides without UK marketing authorisation sit entirely outside the medicines classification when sold under "research use only" framing.

Related: research use only framing · ASA rules on weight-loss advertising.

Reviewed by Oliver Mackman, editorial director · last reviewed 2026-05-18