When Is GLP-1 Suitable?

BMI criteria for GLP-1

International guidelines for GLP-1 therapy for weight loss use one primary criterion: a BMI of 30 kg/m² or higher. The aim is structural improvement of cardiometabolic health, not just cosmetic weight loss.

At a BMI between 27 and 30 (overweight, not formal obesity), GLP-1 is also indicated provided there is one or more weight-related comorbidities. This mirrors the international criteria for pharmacological treatment according to EASO and the ADA.

At a BMI below 27, GLP-1 is not medically indicated for weight loss. Off-label prescribing in this group is discouraged by most doctors because the risk is disproportionate to the possible benefit.

Comorbidity as an additional indication

Weight-related conditions that count as comorbidity: type 2 diabetes or prediabetes, hypertension (blood pressure >140/90), dyslipidaemia (raised LDL or triglycerides, low HDL), obstructive sleep apnoea, non-alcoholic fatty liver disease (MASLD), polycystic ovary syndrome (PCOS), osteoarthritis in weight-bearing joints, cardiovascular disease, asthma, and chronic pain caused by weight.

In confirmed type 2 diabetes, semaglutide (Ozempic) or tirzepatide (Mounjaro) is even first choice after metformin if HbA1c is insufficiently controlled. The indication is then primarily glucose regulation, with weight loss as a welcome side effect.

Contraindications

Absolute contraindications for GLP-1: a personal or family history of medullary thyroid carcinoma, multiple endocrine neoplasia type 2 (MEN2), pregnancy and breastfeeding, and hypersensitivity to the active substance or excipients.

Severe gastroparesis (delayed gastric emptying due to neuropathy or surgery) is a contraindication because GLP-1 slows gastric emptying further. This also applies to recent bariatric surgery (<6 months ago), unless otherwise agreed with the surgeon.

In active pancreatitis or recent pancreatitis (<12 months), GLP-1 is not recommended. Previous pancreatitis without recurrence is a relative contraindication in which the pros and cons are weighed up.

Relative contraindications

Relative contraindications are situations in which GLP-1 is possible, but with extra caution and monitoring: severe renal impairment (eGFR <30), a history of gallbladder disease, diabetic retinopathy (rapid weight loss can cause temporary worsening), a history of eating disorders, severe depression or suicidality.

At a BMI <23 after previous overweight (for example after significant weight loss), there must be a clear medical indication to start or continue GLP-1; cosmetic use outside the indication is discouraged.

Special populations

Pregnancy and breastfeeding: GLP-1 must not be used. Women who wish to become pregnant are advised to stop at least 2 months before conception. GLP-1 has no contraceptive effect, so adequate contraception during use is important.

Children and adolescents: Saxenda and Wegovy are formally registered from the age of 12 for adolescent obesity. Other GLP-1 medicines have so far been studied only to a limited extent in this group.

Older adults over 75: GLP-1 is also effective and safe in older people, provided there is no cognitive decline, malnutrition or sarcopenia. Extra monitoring of protein intake and muscle mass is advisable.

People with a history of eating disorders (anorexia, bulimia): prescribe with great caution, usually only in specialised settings with psychotherapeutic support.

Assessment at Go Leaner

At Go Leaner you go through an intake consultation with a BIG-registered doctor in which BMI, waist circumference, cardiovascular risk, lab values and medical history are assessed. We always ask about previous treatments, medication use, comorbidity and any wish to become pregnant.

Based on this assessment, we advise for or against GLP-1 therapy and which medicine and dose are most appropriate. If GLP-1 is not indicated, we discuss alternatives such as a combined lifestyle intervention (GLI), nutritional therapy or referral to an obesity centre.