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Complete evidence-based review of weight loss medications and injections. Learn which treatments are backed by science, what results to expect, safety considerations, and how prescription medications compare to over-the-counter supplements.
Yes, prescription weight loss injections work—particularly GLP-1 medications like semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound), which achieve 15-25% average body weight loss in clinical trials. Prescription pills like phentermine and Contrave show modest results (5-10% weight loss). However, most over-the-counter weight loss pills are ineffective and not supported by quality research.
The key difference: FDA-approved prescription medications undergo rigorous clinical trials, while OTC supplements have minimal regulation and often make unsubstantiated claims.
Semaglutide, Tirzepatide
Results: 15-25% body weight loss
Phentermine, Contrave, Qsymia
Results: 5-10% body weight loss
OTC fat blocker
Results: 3-5% body weight loss
Garcinia cambogia, green tea extract pills
Reality: No significant weight loss
Hoodia, glucomannan, most OTC options
Reality: Minimal to no effect
Most supplements claiming to "boost metabolism"
Reality: Negligible metabolic effect
GLP-1 (glucagon-like peptide-1) receptor agonists mimic a natural hormone that regulates appetite, blood sugar, and digestion. They work by slowing gastric emptying, reducing hunger signals to the brain, and increasing feelings of fullness.
Clinical Trial Results:
Average 15-20% body weight loss over 68 weeks
FDA Approved:
Yes - Wegovy for weight loss, Ozempic for diabetes
Dosing:
Once-weekly injection, starting at 0.25mg up to 2.4mg
Cost:
$99-$1,350/month depending on provider and formulation
Clinical Trial Results:
Average 20-25% body weight loss over 72 weeks
FDA Approved:
Yes - Zepbound for weight loss, Mounjaro for diabetes
Dosing:
Once-weekly injection, starting at 2.5mg up to 15mg
Cost:
$99-$1,400/month depending on provider and formulation
Most prescribed weight loss pill in the US
Stimulant that suppresses appetite by affecting the central nervous system. Similar mechanism to amphetamines.
5-10% body weight loss over 3-6 months when combined with diet and exercise
Combination medication for long-term use
Combines an antidepressant (bupropion) with an opioid antagonist (naltrexone) to reduce cravings and control appetite.
5-9% body weight loss over 1 year
Combination pill with higher efficacy
Combines appetite suppressant (phentermine) with anti-seizure medication (topiramate) that affects taste and satiety.
8-10% body weight loss over 1 year
Most over-the-counter weight loss supplements are not FDA-approved for weight loss, lack rigorous clinical testing, and show minimal to no significant weight loss in quality studies. The supplement industry is largely unregulated compared to prescription medications.
Only FDA-approved OTC weight loss medication
Blocks absorption of about 25% of fat you eat. Unabsorbed fat is eliminated in bowel movements.
3-5% body weight loss when combined with low-fat diet
Claims: Blocks fat production, suppresses appetite
Reality: Multiple studies show no significant weight loss vs. placebo. May cause digestive issues.
Claims: Boosts metabolism, burns fat
Reality: Minimal effect (0.5-1 lb over months). Just drink green tea instead. High doses can damage liver.
Claims: Burns fat, increases metabolism
Reality: Zero human studies showing weight loss. Animal studies used unrealistic doses.
Claims: Natural appetite suppressant
Reality: No quality studies supporting weight loss. Most products don't contain actual hoodia.
Claims: Fiber supplement that creates fullness
Reality: Minimal weight loss (1-2 lbs). Better to eat actual fiber-rich foods.
Claims: Reduces body fat, builds muscle
Reality: Studies show 1-2 lbs loss at best. May increase insulin resistance and liver fat.
| Medication Type | Avg. Weight Loss | Cost/Month | FDA Approved | Evidence Quality |
|---|---|---|---|---|
| GLP-1 Injections (Semaglutide) | 15-20% | $99-$1,350 | ✓ Yes | Excellent |
| GLP-1 Injections (Tirzepatide) | 20-25% | $99-$1,400 | ✓ Yes | Excellent |
| Qsymia (Rx Pill) | 8-10% | $150-$250 | ✓ Yes | Good |
| Contrave (Rx Pill) | 5-9% | $100-$300 | ✓ Yes | Good |
| Phentermine (Rx Pill) | 5-10% | $30-$100 | ✓ Yes | Good |
| Orlistat/Alli (OTC) | 3-5% | $50-$80 | ✓ Yes | Moderate |
| OTC Fat Burners | 0-2% | $20-$60 | ✗ No | Poor |
FDA-approved GLP-1 injections (semaglutide and tirzepatide) are generally safe when prescribed and monitored by healthcare providers. Common side effects include nausea, diarrhea, and constipation, which usually improve over time. Serious but rare risks include pancreatitis and gallbladder problems. GLP-1s have been used for diabetes treatment for over 15 years with established safety profiles. Always consult a doctor to ensure they're appropriate for your health situation.
Many people regain some weight after stopping GLP-1 medications if they haven't established sustainable lifestyle changes. Studies show average regain of 30-50% of lost weight within 1 year of stopping. However, people who use medication as a tool to develop healthy eating habits, regular exercise, and address underlying behaviors often maintain significant weight loss. Think of GLP-1s as training wheels that help you build new habits, not a permanent solution.
GLP-1 medications are typically taken long-term (1-2+ years) for sustained weight loss and maintenance. Weight loss continues for 12-18 months, then plateaus. Some people stay on a maintenance dose indefinitely, while others slowly taper off once they've established lifestyle changes. Prescription pills like phentermine are only approved for 12 weeks, while others like Contrave can be used long-term. Discuss duration with your doctor based on your goals and response.
Compounded semaglutide and tirzepatide contain the same active ingredient as brand-name versions (Ozempic, Wegovy, Mounjaro, Zepbound) and should be equally effective when properly formulated. However, compounded medications aren't FDA-approved and quality can vary between compounding pharmacies. Choose pharmacies that are FDA-registered 503B facilities with third-party testing. Compounded versions cost $99-$350/month vs. $1,000+ for brand-name, making them accessible to more people.
Generally not recommended. GLP-1 injections are already highly effective (15-25% weight loss) and combining them with other weight loss medications increases side effects without significant additional benefit. Some doctors may prescribe phentermine short-term if GLP-1s alone aren't working, but this should only be done under close medical supervision. Never combine medications without your doctor's approval—interactions can be dangerous.
Yes. Weight loss medications work best when combined with healthy eating and regular physical activity. GLP-1s make it easier to eat less by reducing appetite, but you still need to choose nutritious foods, get adequate protein, and stay active to preserve muscle mass and maximize fat loss. Studies show people who combine medication with lifestyle changes lose 50-70% more weight than medication alone. Think of medication as a powerful tool that makes healthy habits easier to maintain.
Prescription weight loss medications undergo rigorous FDA-approval processes requiring years of clinical trials proving safety and efficacy. OTC supplements have minimal regulation, rarely have quality scientific evidence, and aren't required to prove they work before being sold. Prescription GLP-1s show 15-25% weight loss in clinical trials vs. OTC supplements showing 0-2% at best. The difference is night and day—prescription medications are evidence-based medicine, while most OTC supplements are marketed hope.
Both contain the same active ingredient (semaglutide) and work identically. The only differences are: (1) FDA approval - Ozempic is approved for type 2 diabetes, Wegovy for weight loss, (2) Maximum dose - Wegovy goes up to 2.4mg, Ozempic officially stops at 2.0mg but is often prescribed off-label at 2.4mg, (3) Insurance coverage - insurance may cover Ozempic for diabetes but not Wegovy for weight loss. Functionally, they're the same medication.
Wegovy (semaglutide) is FDA-approved for ages 12+ with obesity (BMI 95th percentile or higher). Saxenda (liraglutide) is approved for ages 12+. These should only be used under close medical supervision as part of a comprehensive weight management program including nutrition counseling and lifestyle changes. Most prescription weight loss pills are not approved for under 18. OTC supplements should be avoided in teenagers—focus on establishing healthy habits instead.
GLP-1 medications must be stopped at least 2 months before trying to conceive due to unknown effects on fetal development. They're contraindicated during pregnancy and breastfeeding. However, weight loss from GLP-1s can actually improve fertility in people with PCOS or obesity-related infertility. If you're planning pregnancy, work with your doctor to safely discontinue medication and maintain weight loss through lifestyle changes. Never take weight loss medications while pregnant or breastfeeding.
On GLP-1 injections: expect 15-20% body weight loss with semaglutide (if you weigh 200 lbs, lose 30-40 lbs) and 20-25% with tirzepatide (40-50 lbs). On prescription pills: expect 5-10% weight loss (10-20 lbs). On OTC supplements: expect 0-3% at best (0-6 lbs). Results vary based on starting weight, adherence, diet quality, exercise, and individual response. Weight loss is gradual—typically 1-2 lbs per week on GLP-1s, with results plateauing around 12-18 months.
Legitimate telehealth providers offer online consultations with licensed healthcare providers who can prescribe weight loss medications if appropriate. Look for HIPAA-compliant platforms with licensed providers, FDA-registered pharmacies, transparent pricing, and real medical oversight. CoreAge RX, for example, offers personalized GLP-1 treatment starting at $99/month with licensed providers and compounded medications from FDA-registered pharmacies. Avoid websites selling "prescription medications" without requiring a real doctor consultation—these are illegal and dangerous.
Get personalized GLP-1 treatment from licensed healthcare providers. Choose from top-rated programs with affordable pricing starting at $99/month, convenient online consultations, and expert support throughout your weight loss journey.
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