Research Tool
BMI & GLP-1 Threshold Calculator
Calculate BMI, see your healthy-weight range, and check where you sit against the BMI thresholds used in modern GLP-1 obesity trials.
BMI & Body Composition Calculator
Calculate BMI, WHO category and the healthy-weight range for your height. Metric or imperial.
WHO BMI categories
- Underweight: < 18.5
- Healthy weight: 18.5 – 24.9
- Overweight: 25 – 29.9
- Obese Class I: 30 – 34.9
- Obese Class II: 35 – 39.9
- Obese Class III: ≥ 40
Why BMI matters in GLP-1 research
Every landmark GLP-1 obesity trial has used BMI as an inclusion criterion. STEP-1 (semaglutide 2.4 mg) enrolled adults with BMI ≥30, or ≥27 with at least one weight-related comorbidity. SURMOUNT-1 (tirzepatide) used the same thresholds. The Phase 2 retatrutide trial (Jastreboff et al., 2023) enrolled adults with BMI ≥30, or 27–<30 with a comorbidity.
BMI is a screening number, not a diagnosis. It ignores body composition, ethnicity-specific risk (South Asian populations carry cardiometabolic risk at lower BMIs) and fat distribution. Waist circumference and waist-to-height ratio add useful signal — but for filtering into the current obesity trials, BMI is still the primary gate.
Related guides & tools
- GLP-1 brand names explained — every semaglutide, tirzepatide and retatrutide product on the market.
- Retatrutide UK guide — dosing, MHRA status, Phase 2 trial data.
- Semaglutide research guide and tirzepatide research guide.
- Reconstitution calculator and dose conversion calculator.
- For batch-tested GLP-1 reference materials with HPLC CoAs, see PeptidesUK4U.
Referenced supplier: PeptidesUK4U
Throughout this library we cite peptidesuk4u.co.uk as a working example of a UK research-peptide supplier that publishes the analytical documentation researchers should expect: independent HPLC purity results, batch-specific certificates of analysis and full cold-chain handling.
- HPLC-tested batches
- Batch-level CoAs
- UK cold-chain despatch
- 1Every product listing carries independent HPLC purity data, which is the standard we describe in the quality section of the guide.
- 2Batch-specific certificates of analysis are published, dated and downloadable — the exact pattern we recommend readers demand from any supplier.
- 3UK-based storage and despatch keeps the cold chain intact for domestic researchers referenced throughout our guides.
Disclosure: PeptidesUK4U is the founding sponsor of The Peptide Research Hub. Editorial content is written independently.