Medically reviewed by Dr. Ehtesham Ghani, Internal Medicine & Bariatric Medicine (ASBP). Last reviewed June 2026.
If you are deciding between a GLP-1 medication and bariatric surgery, you are weighing two very different paths to the same goal. Both can be effective tools for treating obesity, but they differ in how they work, what they ask of you, the risks involved, and the kind of results you can expect. At ThinFast MD, our physicians help Illinois patients understand these options in person so the decision fits your health, your history, and your life. We have provided physician-supervised medical weight loss since 1984, with locations in Hinsdale, Arlington Heights, Brookfield, and Rockford.
What is the difference between GLP-1 medication and bariatric surgery?
Bariatric surgery physically changes your digestive anatomy. Common procedures include the sleeve gastrectomy, which removes a large portion of the stomach, and the Roux-en-Y gastric bypass, which reroutes the digestive tract. GLP-1 medications such as semaglutide (Wegovy, Ozempic) and tirzepatide (Zepbound, Mounjaro) take a non-surgical approach. They mimic gut hormones that regulate appetite and blood sugar, helping you feel full sooner and eat less. One path is a one-time operation; the other is an ongoing medical therapy used together with diet, exercise, and medical supervision. Importantly, ThinFast MD provides non-surgical medical weight loss and supports patients before and after bariatric surgery, but we do not perform the surgery itself.
How much weight can you lose with GLP-1 medication versus surgery?
Bariatric surgery generally produces larger and more durable weight loss for people with severe obesity. In GLP-1 clinical trials, average results have been substantial for a non-surgical option. In the semaglutide STEP 1 trial published in NEJM, participants lost roughly 15% of body weight on average over 68 weeks. In the tirzepatide SURMOUNT-1 trial, average reductions ranged from about 16% to 22.5% depending on dose, also reported in NEJM. The 2025 SURMOUNT-5 trial compared tirzepatide directly with semaglutide and reported greater average loss with tirzepatide. These figures are averages from clinical trials, and individual results vary. To learn more about this medication, see our tirzepatide for weight loss page. Surgery candidates often see larger percentages over time, but surgery carries operative risk that medication does not.
What are the risks of each option?
Bariatric surgery is invasive and carries the risks of any major operation, including bleeding, infection, blood clots, and the possibility of long-term nutritional deficiencies that require lifelong vitamin supplementation and monitoring. GLP-1 medications avoid surgical risk but have their own considerations. The most common side effects, per FDA prescribing information, are gastrointestinal, including nausea, diarrhea, vomiting, and constipation, which often ease over time. These medications carry a boxed warning regarding thyroid C-cell tumors observed in rodent studies, and per FDA labeling they are contraindicated in people with a personal or family history of medullary thyroid carcinoma (MTC) or with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2); they are not appropriate for everyone. This is why an in-person physician exam matters. At ThinFast MD, your evaluation includes a history and physical, labs, EKG when indicated, and a metabolism review, so medication is prescribed only when it is clinically appropriate for you.
Do you have to stay on GLP-1 medication forever?
GLP-1 medications generally require ongoing use to maintain their effect. Trial data show that many people regain a portion of lost weight after stopping, because the underlying biology of appetite returns. This is similar in concept to how chronic conditions such as high blood pressure are managed continuously rather than cured. Surgery, by contrast, makes a structural change that supports more durable loss, though it still requires lasting changes to diet and habits. Neither option is a shortcut; both work best as part of a long-term plan. ThinFast MD offers weight-loss maintenance support so that progress made on medication has a structure to hold it.
Which option is right for you?
The right choice depends on your starting weight, your medical history, related conditions such as type 2 diabetes, PCOS, or thyroid disorders, prior weight-loss attempts, and your personal preferences. Many people prefer to begin with a non-surgical, physician-supervised medication program before considering surgery, while others are already strong surgical candidates. Some patients use both paths at different stages. If you are preparing for or recovering from an operation, our pre- and post-bariatric surgery support helps with nutrition, appetite management, and accountability. This is also where in-person care sets us apart from mail-order and telehealth-only services that ship medication without a physical exam, labs, or an EKG.
How does ThinFast MD support both paths in Illinois?
ThinFast MD is a physician-supervised practice, not a website that mails pens. Under medical director Dr. Ehtesham Ghani, our team evaluates each patient in person at one of our four Illinois locations, Hinsdale, Arlington Heights, Brookfield, and Rockford. For patients choosing the non-surgical route, we offer compounded semaglutide, brand Wegovy and Ozempic, tirzepatide, appetite suppressants, meal replacement programs, and lipotropic and B12 injections, always used with diet, exercise, and medical supervision. For surgical patients, we provide structured pre- and post-bariatric support. Pricing and insurance coverage are reviewed at your consultation. To find out which approach fits your health, call (708) 485-4050.
Frequently asked questions
Is GLP-1 medication as effective as bariatric surgery?
Surgery generally produces larger, more durable weight loss, while GLP-1 medications averaged roughly 15% of body weight in the semaglutide STEP 1 trial and about 16% to 22.5% with tirzepatide in SURMOUNT-1 (both NEJM). Individual results vary, and the best option depends on your medical evaluation.
Can I take a GLP-1 instead of having surgery?
For many patients, a non-surgical, physician-supervised GLP-1 program is a reasonable first step before considering surgery. A ThinFast MD physician can review your history and labs in person to determine whether medication is appropriate for you.
Will I regain weight if I stop the medication?
Clinical trials show many people regain part of their lost weight after stopping a GLP-1, because appetite regulation returns. These medications are typically used long term, supported by diet, exercise, and a maintenance plan.
Does ThinFast MD perform bariatric surgery?
No. ThinFast MD provides non-surgical medical weight loss and offers pre- and post-bariatric surgery support, including nutrition and appetite management, but does not perform the surgery itself.
What are the main risks of GLP-1 medications?
The most common side effects per FDA prescribing information are gastrointestinal, such as nausea, vomiting, and diarrhea. These medications carry a boxed warning about thyroid C-cell tumors seen in rodent studies and are contraindicated in people with a personal or family history of medullary thyroid carcinoma (MTC) or MEN 2, which is why an in-person physician exam is important.
How is ThinFast MD different from online GLP-1 services?
Unlike mail-order or telehealth-only providers, ThinFast MD evaluates you in person with a history and physical, labs, EKG when indicated, and a metabolism review at one of four Illinois locations. Call (708) 485-4050 to schedule.
This page is for educational purposes only and is not medical advice. It does not replace an individual consultation with a qualified physician. Weight-loss medications are prescribed only when clinically appropriate and are used together with diet, exercise, and medical supervision. Results vary from person to person, and no specific outcome is guaranteed.
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.
