In brief: GLP-1 receptor agonists (GLP-1 RAs) are FDA-approved injectable medications that reduce appetite and slow digestion to support meaningful weight loss in qualifying adults. In clinical trials, participants using these medications alongside lifestyle changes lost an average of 10–15% of body weight. Treatment is available at OC Weight Loss & Med Spa in Mission Viejo, CA, under the supervision of Dr. Nezar Dahdal, MD, and requires an initial medical evaluation to confirm candidacy. Results vary by individual, and the medications carry important safety considerations — including a boxed warning regarding thyroid tumors — that your provider will review with you.
Medically reviewed by the clinical team at OC Weight Loss and Med Spa. Last updated: June 12, 2026.
What Are GLP-1 Receptor Agonists?
GLP-1 receptor agonists are a class of injectable medications that mimic glucagon-like peptide-1, a hormone the gut naturally releases after eating. Originally developed to manage type 2 diabetes, these drugs were subsequently found to produce substantial weight loss, leading the FDA to approve specific formulations for chronic weight management in adults with obesity or weight-related health conditions.
Semaglutide (brand names Ozempic for diabetes, Wegovy for weight management) and liraglutide (Saxenda) are the most widely studied agents in this class. Tirzepatide (Zepbound), which targets both GLP-1 and GIP receptors, received FDA approval for weight management in 2023 and has shown higher average weight-loss outcomes in trials. Your provider will discuss which agent, if any, is appropriate for your medical profile.
How GLP-1 RAs Support Weight Loss
These medications work through several complementary mechanisms:
- Appetite reduction. GLP-1 RAs act on receptors in the hypothalamus to reduce hunger signals, so patients typically feel satisfied with smaller meals.
- Slowed gastric emptying. Food moves through the stomach more slowly, prolonging the feeling of fullness after eating.
- Blood sugar regulation. By stimulating insulin release in a glucose-dependent manner, these agents also help stabilize blood sugar — a meaningful benefit for patients with prediabetes or type 2 diabetes.
- Behavioral reinforcement. Reduced hunger makes it easier to maintain a lower-calorie diet, which amplifies the medication’s effect when combined with lifestyle changes.
In the STEP clinical trial program for semaglutide 2.4 mg, participants lost an average of approximately 15% of body weight over 68 weeks when combined with lifestyle intervention. Individual results vary.
Who May Qualify
FDA-approved weight-management indications for GLP-1 RAs generally include adults who meet one of the following criteria:
- BMI of 30 or above (classified as obesity)
- BMI of 27 or above with at least one weight-related health condition, such as hypertension, type 2 diabetes, or high cholesterol
Candidacy is always determined at a medical consultation. Your provider at OC Weight Loss & Med Spa will review your full health history, current medications, and treatment goals before recommending a specific medication and dose.
What to Expect During Treatment
GLP-1 RAs are typically administered as a once-weekly subcutaneous injection in the abdomen, thigh, or upper arm. Most patients self-inject at home after a brief training session at the clinic.
Dosing follows a titration schedule — starting low and increasing gradually over several weeks — to minimize gastrointestinal side effects and allow the body to adjust. Regular follow-up appointments allow your provider to monitor progress, adjust the dose, and address any concerns.
These medications work best as part of a broader program. At OC Weight Loss & Med Spa, care is supervised by Dr. Nezar Dahdal, MD, a board-certified internist, and delivered by Lindsay Short, NP, a board-certified Nurse Practitioner (UCLA, Columbia MSN). The program integrates medication management with nutritional guidance and ongoing support.
Safety, Side Effects, and Who Should Not Use GLP-1 RAs
GLP-1 RAs are prescription medications with a defined safety profile. Understanding the risks is an important part of the decision to start treatment.
Common side effects include nausea, vomiting, diarrhea, constipation, and abdominal discomfort. These are most pronounced during the dose-escalation phase and typically lessen over time. Eating smaller, lower-fat meals and staying well hydrated can help manage them.
Boxed warning — thyroid C-cell tumors. In animal studies, GLP-1 RAs caused thyroid C-cell tumors at clinically relevant exposures. It is not known whether this risk translates to humans, but these medications are contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Your provider will screen for these conditions before prescribing.
Other important contraindications and precautions:
- Pancreatitis. GLP-1 RAs have been associated with acute pancreatitis. Patients with a history of pancreatitis are generally not candidates.
- Gallbladder disease. Rapid weight loss with any method can increase gallstone risk; GLP-1 RAs may contribute an additional risk. Notify your provider of any prior gallbladder issues.
- Pregnancy and breastfeeding. These medications should be discontinued at least two months before a planned pregnancy and are not used during pregnancy or breastfeeding.
- Diabetic retinopathy. Rapid glucose improvement in patients with diabetes has been associated with worsening of diabetic retinopathy in some cases; closer monitoring may be needed.
- Drug interactions. Because gastric emptying slows, the absorption of oral medications may be affected. Inform your provider of all medications and supplements you take.
This is not a complete list of risks. Your provider will review the full prescribing information with you at your consultation.
Frequently Asked Questions
How quickly do GLP-1 RAs produce noticeable weight loss?
Most patients begin noticing reduced appetite within the first few weeks. Measurable weight changes are typically visible within the first month of treatment, though progress accelerates as the dose increases. Clinical trial data suggest the most significant losses occur between weeks 12 and 36. Individual results vary considerably based on starting weight, diet, activity level, and adherence.
Will I regain weight if I stop the medication?
Research shows that a meaningful portion of lost weight is typically regained within one to two years of stopping a GLP-1 RA, particularly if lifestyle habits have not changed. This reflects the underlying biology of obesity, not a failure of effort. Your provider can discuss long-term maintenance strategies, which may include continued medication, periodic check-ins, or other approaches tailored to your goals.
Is the medication covered by insurance?
Coverage varies significantly by insurance plan and the specific medication prescribed. Wegovy and Zepbound have broader coverage for obesity than Ozempic, which is primarily approved for diabetes. OC Weight Loss & Med Spa offers flexible financing through Cherry and CareCredit to help make treatment accessible where insurance does not fully cover the cost. Our team can help review your options during your consultation.
Do I need to follow a specific diet while on GLP-1 RAs?
There is no single mandated diet, but patients generally do best eating smaller, balanced meals that are lower in fat and refined sugar. Large, high-fat meals can worsen nausea during the early weeks of treatment. Your provider or care team will offer practical nutritional guidance as part of your program at OC Weight Loss & Med Spa.
How is treatment at OC Weight Loss & Med Spa different from getting a prescription online?
In-person care allows for a thorough medical evaluation, physical exam findings, and ongoing monitoring that a remote encounter may not capture. Dr. Dahdal and Lindsay Short, NP, oversee each patient’s program directly, adjusting treatment based on how the patient is responding — not just a self-reported questionnaire. Patients in Mission Viejo and surrounding South Orange County benefit from consistent, relationship-based care rather than a transactional prescription model.
Schedule a Free Consultation in Mission Viejo
If you are considering GLP-1 receptor agonist therapy for weight management, the first step is a medical evaluation to determine whether you are a candidate and which medication, if any, fits your health profile. OC Weight Loss & Med Spa offers free consultations at our Mission Viejo clinic, Monday through Friday 9 a.m.–5 p.m. and Saturday 9 a.m.–1 p.m. Financing through Cherry and CareCredit is available.
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