Do Weight Loss Pills and Injections Work?

Let's cut to the chase: FDA-approved prescription weight loss medications do work, and some work remarkably well. But there are important caveats: • Results vary significantly between different medications • They work best when combined with lifestyle changes • They typically need to be taken long-term • They don't work equally well for everyone • They come with side effects and costs The most effective modern medications—GLP-1 receptor agonists like semaglutide and tirzepatide—have changed what's possible with pharmaceutical weight loss. But older medications also have their place for certain patients.

GLP-1 receptor agonists represent the most significant advance in obesity treatment in decades. Semaglutide (Wegovy, Ozempic): The STEP clinical trials demonstrated average weight loss of 15-17% of body weight over 68 weeks. Some patients lost over 20%. This rivals results typically seen only with bariatric surgery. Tirzepatide (Zepbound, Mounjaro): Even more impressive, the SURMOUNT trials showed average weight loss of 20-26% of body weight. Tirzepatide is a dual GIP/GLP-1 agonist, which may explain its enhanced effectiveness. How they work: • Reduce appetite and food cravings • Slow stomach emptying, increasing fullness • Improve blood sugar regulation • May affect brain reward pathways related to food These medications represent a paradigm shift—obesity is increasingly recognized as a chronic medical condition that responds to medical treatment, not simply a failure of willpower.

Before GLP-1 medications, several other prescription options were available. They're still used, though generally considered less effective: Phentermine: • One of the oldest weight loss drugs (since 1959) • Appetite suppressant (stimulant) • Typically 5-10% weight loss • Only approved for short-term use (12 weeks) • Can increase heart rate and blood pressure Phentermine-Topiramate (Qsymia): • Combination medication • Average 7-10% weight loss • Can be used long-term • Side effects include cognitive issues, tingling, dry mouth Naltrexone-Bupropion (Contrave): • Combination affecting reward pathways • Average 5-8% weight loss • Can help with food cravings • Not for those with seizure disorders Orlistat (Xenical, Alli): • Blocks fat absorption • Modest weight loss (3-5%) • Significant GI side effects • Available over-the-counter as Alli

Clinical trial data gives us the clearest picture of what to expect: Response rates matter: Not everyone responds to weight loss medications. In clinical trials, typically 30-50% of participants don't achieve meaningful weight loss (usually defined as >5% of body weight). However, the response rate for GLP-1 medications is higher than older options. Placebo-adjusted results: When you see headlines about weight loss percentages, understand that some weight loss occurs even with placebo (diet and exercise alone). The medication's true effect is the difference between drug and placebo groups. Long-term maintenance: Most studies show weight regain after stopping medication. This doesn't mean the medications don't work—it means obesity is a chronic condition often requiring ongoing treatment, similar to high blood pressure or diabetes. Real-world vs. clinical trial results: Clinical trial participants often receive more support and monitoring than typical patients. Real-world results may be somewhat lower, though still clinically meaningful.

FDA-approved weight loss medications are intended for: Medical eligibility: • BMI ≥30 (obesity), OR • BMI ≥27 with at least one weight-related health condition (diabetes, high blood pressure, high cholesterol, sleep apnea, etc.) Best candidates: • Those who have tried diet and exercise without adequate results • People with weight-related health conditions that would improve with weight loss • Individuals committed to lifestyle changes alongside medication • Those who can afford and access the medications Not ideal for: • People looking for a quick fix without lifestyle changes • Those with certain medical conditions (varies by medication) • Pregnant or breastfeeding women • People with a history of eating disorders (requires careful evaluation)

Effectiveness is only part of the equation—cost is a major barrier for many: Brand-name GLP-1 medications: • Wegovy: ~$1,300-1,400/month without insurance • Zepbound: ~$1,000-1,100/month without insurance • Insurance coverage varies widely Compounded alternatives: • Compounded semaglutide: $200-500/month • Less regulated than brand-name medications • Quality varies between pharmacies Older medications: • Phentermine: $30-100/month (generic available) • Qsymia: $200-300/month • Contrave: $100-300/month • Orlistat (Alli): $50-70/month OTC The cost-effectiveness calculation includes not just the medication price, but potential savings from improved health—fewer diabetes medications, lower cardiovascular risk, reduced joint problems, and better quality of life.

All medications come with potential downsides: GLP-1 medications common side effects: • Nausea (very common, usually improves) • Vomiting • Diarrhea or constipation • Fatigue • Headache GLP-1 serious but rare risks: • Pancreatitis • Gallbladder problems • Thyroid tumors (warning based on animal studies) Stimulant-based medications: • Increased heart rate • Elevated blood pressure • Insomnia • Anxiety • Potential for dependence Fat absorption blockers: • Significant GI effects • Oily stools • Urgency • Vitamin deficiency risk Most side effects are manageable and many decrease over time. Your healthcare provider can help you weigh risks against benefits for your specific situation.

The supplement industry makes billions selling weight loss products, but the evidence is largely disappointing: Caffeine/stimulants: Modest, temporary effects. Not recommended in high doses. Green tea extract: Minimal effect, some liver concerns at high doses. Garcinia cambogia: No convincing evidence of effectiveness. Raspberry ketones: No human evidence supporting weight loss claims. "Fat burners": Marketing terms with no regulatory meaning. CLA (Conjugated Linoleic Acid): Very modest effects if any. The key difference: Prescription medications undergo rigorous FDA approval requiring proof of safety and effectiveness. Supplements have no such requirement—they only need to not be actively harmful. If a supplement worked as well as claimed, it would be a prescription drug.

Maximize your results with these strategies: Combine with lifestyle changes: Medications work best alongside improved diet and increased physical activity. Studies consistently show better outcomes with combined approaches. Follow the prescribed protocol: Take medications as directed. For GLP-1s, proper titration schedules help minimize side effects and optimize results. Track your progress: Monitor weight, measurements, and how you feel. This helps identify what's working and allows for adjustments. Address barriers: Work with your healthcare team on challenges like side effects, cost, access, or lifestyle factors. Set realistic expectations: Even highly effective medications don't make everyone thin. A 15-20% weight loss is excellent and provides significant health benefits. Plan for the long term: Weight loss medications are typically most effective when continued indefinitely. Discuss long-term plans with your provider.