Medically reviewed by Dr. Ehtesham Ghani, Internal Medicine & Bariatric Medicine (American Society of Bariatric Physicians). Last reviewed June 2026.
At ThinFast MD, tirzepatide (the active medication in Zepbound® and Mounjaro®) is prescribed and monitored by a physician as part of a complete, individualized weight-loss program — not mailed out without oversight. We’ve helped patients lose weight safely since 1984, with in-person evaluation at our Hinsdale, Arlington Heights, Brookfield, and Rockford, IL locations.
What is tirzepatide?
Tirzepatide is a once-weekly injectable medication that activates two gut hormone receptors — GIP and GLP-1. Together these help reduce appetite, slow stomach emptying, and improve how your body manages blood sugar, making it easier to eat less and lose weight when combined with diet, exercise, and medical support.
How well does tirzepatide work?
In clinical trials, adults taking tirzepatide alongside lifestyle changes lost roughly 15–21% of body weight on average over about 72 weeks, depending on dose. In the head-to-head SURMOUNT-5 trial (NEJM, 2025), tirzepatide produced greater average weight loss than semaglutide (about 20% vs. 14%). Individual results vary, and medication works best as part of a supervised program — it is not a guarantee of any specific result.
Tirzepatide vs. semaglutide — which is right for you?
Both are effective. Tirzepatide has shown higher average weight loss in trials, while semaglutide has a longer track record and may suit different patients and budgets. The right choice depends on your health history, goals, tolerance, and coverage — which our physician reviews with you at your visit.
Who is a candidate?
Tirzepatide is generally considered for adults with a BMI of 30 or higher, or 27 or higher with a weight-related condition such as high blood pressure, type 2 diabetes, or sleep apnea. Every candidate receives a medical evaluation — history and physical, lab work, and a metabolism review — before any medication is prescribed.
Side effects and how we manage them
The most common side effects are gastrointestinal — nausea, constipation, or diarrhea — and are usually mild and temporary. We start at a low dose and increase gradually (titration), and support you with nutrition guidance and protein/resistance-training advice to help preserve muscle. Because you’re monitored in person, we can adjust your plan if needed.
Physician-supervised care since 1984
Unlike mail-order GLP-1 services, ThinFast MD provides a real medical exam, in-office support, and a board-certified bariatrician overseeing your care. Pricing and insurance options are reviewed transparently at your consultation.
Frequently asked questions
How much weight can you lose on tirzepatide?
In trials, average loss was about 15–21% of body weight over ~72 weeks with diet and exercise, depending on dose. Individual results vary.
Is tirzepatide better than semaglutide?
The SURMOUNT-5 head-to-head trial showed greater average weight loss with tirzepatide, but the best option depends on your individual health, tolerance, and goals.
How much does tirzepatide cost?
Cost depends on dose and whether you use insurance or a cash program. We review your options transparently at your consultation — call (708) 485-4050.
What are the most common side effects?
Mostly mild, temporary gastrointestinal effects such as nausea or constipation, minimized by gradual dose increases and medical support.
Do I qualify for tirzepatide?
Generally a BMI of 30+, or 27+ with a weight-related condition, after a medical evaluation. The only way to know is a consultation with our physician.
This page is for general education and is not medical advice. Weight-loss medications are prescribed only when clinically appropriate and used with diet, exercise, and medical supervision. Results vary by individual.
Find your nearest ThinFast MD clinic
We serve patients across the Chicago suburbs and Rockford. Choose your nearest location — Hinsdale, Arlington Heights, Brookfield, or Rockford — or call (708) 485-4050 to book. See all service areas.
