Semaglutide Injection (Ozempic/Wegovy)

Overview

Semaglutide injection (Ozempic for diabetes, Wegovy for weight management) is a long-acting GLP-1 receptor agonist with a roughly 7-day half-life, enabling once-weekly subcutaneous dosing. A C18 fatty diacid chain binds serum albumin, extending circulation time far beyond native GLP-1 (which DPP-4 degrades within minutes). It mimics the incretin hormone GLP-1, stimulating glucose-dependent insulin release, suppressing glucagon, slowing gastric emptying, and reducing appetite through central pathways. The standard titration escalates every 4 weeks (0.25 to 0.5 to 1.0 to 1.7 to 2.4 mg for Wegovy) to manage gastrointestinal side effects. Steady state is reached after approximately 5 weeks at each dose level. Clinical trials showed up to 15% weight loss at 68 weeks. Key harm-reduction concerns include dose-dependent nausea and vomiting, delayed gastric emptying affecting oral medication absorption, muscle loss without adequate protein and resistance training, and the critical importance of patient titration to avoid severe GI effects.

Pharmacokinetic summary

Model tier

Advanced (t½ + Cmax + Tmax + F)

Half-life

7 days

Cmax

2879.1 nmol/L

Tmax

1.3 days

Bioavailability

89%

Typical dose

0.25–2.4 mg