How fast does semaglutide start to work?

When you start taking semaglutide, whether for weight management or blood sugar control, it can take some time before you notice the medication’s effects. We spoke to Dr. Felix Gussone, MD, about how fast semaglutide starts to work.

Semaglutide is the active ingredient in popular diabetes and weight loss drugs, such as Ozempic (approved for type 2 diabetes), and Wegovy and Saxenda (approved for weight loss).

Once you inject semaglutide, it starts working on receptors in your body soon after the first dose. But that doesn’t mean that you’ll see results right away. If you’ve just started taking semaglutide, either to control blood sugar levels, to lose weight, or both, it might take a bit longer until you see your weight going down, and your blood sugar control improving. 

If you’re taking semaglutide for weight loss, it is possible that you’ll have less of an appetite after a couple of weeks of continuous use of semaglutide, but significant weight loss takes a little bit longer. Weight loss is a complex process, and how fast you lose weight on semaglutide varies, with some people experiencing initial weight loss within a few weeks, and others seeing results closer to the eight-week mark. A clinical trial with people who combined semaglutide with a healthy diet and exercise lost an average of over 4% of their body weight after eight weeks. Those who took the highest dose of semaglutide (2.4 mg per week) lost an average of 10.6% of their body weight in the first 20 weeks of treatment. If you’re taking semaglutide to control diabetes type 2, it also may take several weeks to achieve the full effect. According to the manufacturer of semaglutide, the concentration of the drug in the blood stream typically reaches a steady level after 4 to 5 weeks of once-weekly use. 

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Current version

October 27, 2023

Written by

Felix Gussone, MD

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.