Do weight loss pills work?

Effectiveness of weight loss pills

Prescription medications can help with long-term weight loss — with the right lifestyle changes. Without medication, "(people often regain) 50% of lost weight within two years, and 80% within five years," Dr. Richele Corrado, an obesity medicine physician at Revolution Medicine, Health & Fitness, noted. These pills help counter the body's natural tendency to regain weight.

Once in your system, these medications work through various pathways to control hunger and metabolism. “Phentermine is a norepinephrine reuptake inhibitor. … They work as appetite suppressants,” explained Dr. Evan Nadler, a childhood obesity treatment pioneer and founder of Obesity Explained. Some target brain chemistry to reduce appetite, while others, like orlistat, block fat absorption in your digestive system.

If you’re considering obesity pills, skip the supplement aisle and consult your doctor. Research consistently shows that prescription pills outperform non-prescription ones. Dr. Corrado said over-the-counter pills, such as Alli, often result in “less than 3% total body weight loss.” And Dr. Nadler stated bluntly, “I’m not aware of over-the-counter options that work at all.”

Even with prescription medications, results vary from person to person. This variation stems from your genetic makeup, which influences how your body processes and responds to these medications. Diet and exercise habits impact results, too. “(Outcomes) are relatively durable if (you make) lifestyle changes in conjunction with their use,” Nadler emphasized.

Safety concerns and side effects

“Obesity medications are effective, with decades of clinical use supporting their safety,” Corrado said. However, not all weight loss pills are equally safe for everyone. “Phentermine has cardiovascular side effects, (so you must use it) with caution or not at all (if you have) high blood pressure,” Nadler cautioned.

Medical conditions can limit which weight loss pills work safely for you. For example, you should avoid phentermine if you have severe anxiety or hyperthyroidism. Nadler emphasizes the importance of taking anti-obesity medication only under the supervision of a health care professional.

Where you get your weight loss pills also matters. “FDA-approved medications have undergone appropriate regulatory oversight and list the contraindications on the package inserts,” Dr. Nadler pointed out. “But those that may be available from compounding pharmacies have not.” This distinction highlights why you should get pills only through licensed health care providers.

Common side effects vary by medication but often include the following:

• Digestive issues (e.g., nausea, constipation, diarrhea)
• Dry mouth
• Headaches and dizziness
• Mood changes
• Sleep disturbances
• Vomiting

“(These side effects) are generally manageable with guidance and close follow-up from a health care provider,” Corrado noted. Most diminish over time as your body gets used to the medicine.

A word of warning

Avoid weight loss pills if you’re pregnant or planning to become pregnant, have uncontrolled blood pressure, severe heart disease, a history of medullary thyroid cancer or multiple endocrine neoplasia. Discuss your complete medical history with your doctor, who can then prescribe the safest and most effective approach.

Alternatives to weight loss pills

“Bariatric surgery is the safest (alternative for) significant and sustained weight loss,” said Nadler. Procedures including gastric bypass and sleeve gastrectomy modify your digestive system to limit food intake or absorption, delivering substantial results that pills often can’t match.

Some patients find intensive behavioral therapy for obesity helpful. This addresses the psychological aspects of weight management. Working with a therapist will help you identify emotional eating patterns, develop coping strategies for stress without food and build a healthier relationship with eating.

Temporary devices are another possible solution. According to Corrado, gastric balloons are “effective alternatives or adjuncts to obesity medications.” These non-surgical interventions help you feel fuller faster while you work on healthier eating habits.

Finally, balanced meals and regular physical activity are critical for managing weight, maintaining muscle mass and reducing the risk of conditions such as heart disease and diabetes. But alone, Corrado noted, these efforts typically yield just “2% to 10% total body weight loss.” Nadler suggested they might drop five to seven pounds at most.

Pro tip

Most patients see promising results with a comprehensive approach. Create a holistic plan by combining the right weight loss medication options with diet and exercise. This strategy tackles the biological factors (e.g., metabolism and hunger hormones) and the everyday habits that affect your weight.

» COMPARE: Weight loss medication options

Consulting your doctor

Talking to your doctor about obesity treatment can be incredibly daunting. To make it easier, research available medications and their potential benefits for your situation before booking your appointment. The Obesity Action Coalition is a great place to start.

After becoming familiar with what’s out there and what could work for you, prepare specific questions for the doctor:

• What weight loss medication or treatment(s) might work best for my body? Why?
• What side effects should I expect to experience, and for how long?
• What kind of weight loss results may I realistically expect?
• How will these pills interact with my current medications? (if you’re taking any)
• Will my insurance cover this medication, and if not, what are the costs?
• How long would I need to take this medication?
• What lifestyle changes should I make to see the best results with medical treatment?

Nadler encourages advocating for yourself during the appointment. “If you want an anti-obesity medication, (you) should definitely bring it up,” he urged. Share your weight loss history, including previous efforts and challenges. This information helps your doctor understand your journey and create a personalized treatment plan.

Pro tip

“Some providers won’t prescribe weight loss drugs no matter what. So, be prepared to ask for a referral or find a specialist yourself,” Nadler advised. Resources such as the American Board of Obesity Medicine provide directories to help you find obesity medicine specialists in your area.

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