GLP-1 Medications Explained: Ozempic, Wegovy, Mounjaro, Zepbound
GLP-1 medications are the biggest advance in weight management in decades — but the marketing has outrun the education. Here's the physician view.
How they actually work
GLP-1 (glucagon-like peptide-1) is a hormone your gut releases when you eat. It slows stomach emptying, signals the pancreas to release insulin appropriately, and signals the brain that you're satisfied. In people with obesity and type 2 diabetes, the natural GLP-1 response is blunted.
Semaglutide (Ozempic, Wegovy, Rybelsus) and tirzepatide (Mounjaro, Zepbound) are long-acting analogues of these hormones. Tirzepatide adds action on GIP, a related hormone, which explains its stronger weight-loss effect in trials.
Who benefits most
Health Canada indications for weight management typically require a BMI ≥ 30, or ≥ 27 with at least one weight-related condition (type 2 diabetes, hypertension, dyslipidemia, sleep apnea). Off-label use outside these criteria exists but should be discussed transparently.
Patients with type 2 diabetes, prediabetes with high HbA1c, non-alcoholic fatty liver disease, PCOS, or significant sleep apnea tend to see the largest metabolic wins in addition to weight change.
Side effects worth knowing
Most side effects are gastrointestinal — nausea, reflux, constipation or diarrhoea. They typically appear during dose escalation and improve as the body adapts, which is why slow titration matters.
Serious but rare risks include pancreatitis, gallbladder disease, and — in tirzepatide — accelerated diabetic retinopathy in poorly controlled diabetes. A personal or family history of medullary thyroid cancer or MEN2 is a contraindication.
The most under-discussed risk is muscle loss: with any large weight loss, roughly 20–40% of what you lose can be lean mass unless you actively protect it with adequate protein (1.6+ g/kg/day) and resistance training.
What proper monitoring looks like
Baseline labs: CBC, comprehensive metabolic panel, HbA1c, TSH, lipid panel, urinalysis.
3-month check-in: weight, waist, blood pressure, tolerability, dose adjustment. Repeat HbA1c if diabetic.
6-month labs: repeat metabolic and lipids to document improvement, ferritin/B12 to catch nutrition gaps.
Annual: full re-assessment. If treatment goal reached, discuss maintenance dose vs slow taper vs continued therapy.
Frequently asked questions
How much does GLP-1 treatment cost in Quebec?+
Retail costs vary from roughly $250 to $500+ per month depending on the medication and dose. Private insurance coverage varies; some plans cover it for type 2 diabetes but not for weight management alone. Discuss with your insurer.