From the FDA Drug Label
Maximum concentration of semaglutide is reached 1 to 3 days post dose.
The onset of action for the first dose of Semaglutide injection is not explicitly stated in the provided drug labels. However, based on the information that the maximum concentration of semaglutide is reached 1 to 3 days post dose, it can be inferred that the onset of action may occur within this timeframe.
- Onset of action: 1 to 3 days post dose
- Key points:
- Maximum concentration reached in 1 to 3 days
- No explicit statement on onset of action 1
From the Research
Semaglutide begins working in the body shortly after injection, but patients typically notice clinical effects within 2-4 weeks after the first dose, as the medication reaches peak blood levels within 1-3 days following subcutaneous administration, though the full glucose-lowering effect builds gradually over time. The medication works by mimicking the incretin hormone GLP-1, which stimulates insulin secretion when blood glucose is high, suppresses glucagon release, slows gastric emptying, and reduces appetite through central nervous system effects. According to the most recent study 2, once-weekly semaglutide resulted in significant reductions in weight, body mass index (BMI), and glycated hemoglobin (HbA1c) outcomes from baseline to 1 year post-index, with mean changes in weight (kg) of -4.4, BMI (kg/m2) of -1.5, and HbA1c (%) of -1.5. Some key points to consider when prescribing semaglutide include:
- The medication has a half-life of 7 days, and it would reach steady state in 4-5 weeks, as reported in the study 3.
- Semaglutide can delay gastric emptying and may impact the absorption of oral medications, as noted in the study 3.
- The full metabolic and weight management benefits of semaglutide typically develop over several weeks to months of consistent use, with maximum effects seen after dose titration is complete, as described in the study 4.
- Patients should understand that while some may experience early effects on appetite or fullness, the full benefits of semaglutide may take time to develop, as discussed in the study 5.