What is the onset of action for Ozempic (semaglutide) and is a preliminary increase in appetite ever reported?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 5, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Research

Ozempic (semaglutide) typically begins to work within the first week of treatment, but its full therapeutic effect may take 4-8 weeks to develop as the dose is gradually increased according to the standard titration schedule, as supported by the most recent study 1. Most patients start at 0.25 mg once weekly for 4 weeks, then increase to 0.5 mg weekly, with possible further increases to 1 mg or 2 mg weekly if needed for glycemic control. Regarding appetite, Ozempic generally decreases rather than increases appetite, as this is one of its primary mechanisms for promoting weight loss, with studies showing a weight loss of about 12-15% 1. However, some patients may experience a temporary increase in appetite when the medication is wearing off toward the end of the weekly dosing interval, sometimes called the "Ozempic wearing off" phenomenon. This occurs because semaglutide levels in the blood decrease over time after injection, potentially leading to a brief rebound in appetite before the next scheduled dose, as described in a study on the pharmacokinetics of semaglutide 2. If this occurs, it's essential to maintain consistent weekly dosing and discuss with your healthcare provider, who might adjust your treatment plan. The appetite-suppressing effect of Ozempic works through its action on GLP-1 receptors in the brain that regulate hunger signals and slow gastric emptying, helping you feel fuller longer, as explained in a review of GLP-1 receptor agonists 3. Key points to consider:

  • Ozempic's onset of action is within the first week, with full effect at 4-8 weeks
  • Appetite is generally decreased, but temporary increases can occur at the end of the dosing interval
  • Semaglutide's action on GLP-1 receptors promotes weight loss and reduces appetite
  • Consistent dosing and potential adjustments by a healthcare provider are crucial for managing appetite and therapeutic effects.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.