How long does it take Mounjaro (tirzepatide) to start working?
Mounjaro® starts to work as soon as you take your first dose, but not everyone notices an effect immediately. The dose of the medication is gradually increased each month so that the body can adjust to the medication while reducing the risk of more severe side effects that can occur if a higher dose is taken too soon.
Specifically concerning Mounjaro weight loss, some patients notice an immediate reduction in appetite, while others require higher doses to see effects. The rate at which someone loses weight depends on numerous factors including caloric intake, age, activity level, and other medications a person may be taking. Therefore, there is not a standard expected rate of weight loss. A study found that by week 24 patients taking the higher doses of Mounjaro (10 mg and 15 mg) had lost on average close to 15% of their starting body weight. Keep in mind that Mounjaro is currently only FDA-approved for treatment of type 2 diabetes to lower blood sugar levels and can start to lower blood sugar levels soon after starting. A study found that by 40 weeks the average hemoglobin A1c (a marker for blood sugar control) dropped by 2.11% in patients with diabetes taking the highest dose of their Mounjaro prescription.
Lauren Lemieux, MD, FACP, ABOM diplomate
Dr. Lauren Lemieux completed her Internal Medicine residency and fellowship in Clinical Nutrition at UCLA. She is board certified in Internal Medicine and diplomate of the American Board of Obesity Medicine, and as a Physician Nutrition Specialist. She is also a fellow of the American College of Physicians. Dr. Lemieux is passionate about helping her patients reach their health goals using personalized nutrition, lifestyle and weight management strategies.
