Semaglutide

How it works

A GLP-1 agonist: it releases insulin when blood sugar is high, lowers glucagon, slows down the stomach and acts on the brain’s appetite centers.

What it is used for

Type 2 diabetes (Ozempic), long-term weight management (Wegovy) and lowering cardiovascular risk.

What the evidence says

In the STEP trials, people lost about 15% of their weight in 68 weeks. The SELECT trial showed 20% fewer heart attacks and strokes in people with obesity.

Side effects and cautions

Nausea, vomiting, diarrhea and constipation are common. Gallbladder problems and pancreatitis are possible. Not for people with a history of medullary thyroid cancer or MEN2. Some muscle is lost along with fat, and weight usually returns after stopping.

Half-life

About 1 week (label)

Makes sense for

• Adults with obesity, or overweight with a weight-related condition
• Type 2 diabetes

Does not make sense for

• Type 1 diabetes
• A history of pancreatitis
• Medullary thyroid cancer or MEN2
• People at a healthy weight

Boost the effect

• High-protein meals (about 1.2–1.6 g per kg of body weight a day): help keep muscle while you lose weight
• Strength training 2–3 times a week: protects muscle and strength
• Plenty of water and fiber: ease the usual constipation and nausea