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Metabolic

Tirzepatide

Mounjaro · Zepbound

The drug behind Mounjaro, and the most-used GLP-1 among people paying privately in the UK. It works like semaglutide but hits two hormone pathways instead of one, which is generally why the weight loss tends to be larger.

Dual / — the most-prescribed drug in the UK private market.

How well studied

Tier Guide: A = Well studied, B = Some good studies, C = Early evidence & D = Barely studied

AHow well studiedWell studied

Backed by large human trials — we have solid data on how it works and what it does.

How it works

Copies two different gut hormones at once instead of one, which is why appetite tends to drop more than it does with single-pathway drugs.

Activates two gut pathways ( and ) simultaneously for stronger appetite and metabolic effects than single-pathway drugs.

Reported benefits

  • Largest weight loss of any licensed UK drug (~20% average in trials)
  • Improves blood glucose control
  • Improves lipid markers

Who it's typically used for

Adults with obesity or overweight with a weight-related comorbidity; type 2 diabetes

Timeline to results

Appetite change within days; meaningful weight loss visible by week 8-12; full effect over 12+ months of titration

Dosage

Approved dose

Titrated from 2.5mg to 15mg weekly per MHRA label, under prescriber supervision

Side effects

  • Nauseacommon, especially during dose escalation
  • Diarrhoeacommon
  • Vomitingless common
  • Injection site reactionsoccasional

Getting it in the UK

Getting it in the UKA doctor can prescribe it

A doctor can prescribe this the normal way, like anything from a pharmacy — officially checked and approved for this use.

MHRA: the UK government body that checks a medicine is safe and actually works before doctors are allowed to prescribe it.

Content freshness

Last reviewed
11 Aug 2026
Regulatory status last checked
11 Aug 2026