Weight loss medication comparison chart
Every FDA-approved weight loss medication at PEAK, compared side by side.
The complete comparison
Five FDA-approved weight loss medications. Different mechanisms, different price points, different strengths. Here's how they stack up across every factor that matters.
| Wegovy semaglutide | Zepbound tirzepatide | Phentermine phentermine HCl | Saxenda liraglutide | Contrave naltrexone/bupropion | |
|---|---|---|---|---|---|
| Drug class | GLP-1 agonist | GLP-1/GIP dual agonist | Sympathomimetic amine | GLP-1 agonist | Opioid antagonist + antidepressant |
| Administration | Weekly injection | Weekly injection | Daily tablet | Daily injection | Twice-daily tablet |
| Avg. weight loss | ~15% | 18–22.5% | 5–10% | ~8% | ~5–6% |
| FDA-approved | 2021 | 2023 | 1959 | 2014 | 2014 |
| Cost without insurance | ~high out-of-pocket pricing | ~high out-of-pocket pricing | low monthly generic pricing | ~high out-of-pocket pricing | moderate monthly out-of-pocket pricing |
| Cost with insurance | low monthly copays for eligible commercially insured patients | low monthly copays for eligible commercially insured patients | lowest copays for eligible plans | low copays for eligible plans | low copays for eligible plans |
| Insurance coverage | Most major plans | Growing rapidly | Most plans | Many plans | Many plans |
| Duration of use | Ongoing | Ongoing | Up to 12 weeks | Ongoing | Ongoing |
| Titration period | 16–20 weeks | 16–20 weeks | None | 4–5 weeks | 4 weeks |
| Main side effects | Nausea, constipation, vomiting | Nausea, diarrhea, vomiting | Dry mouth, insomnia, jitteriness | Nausea, diarrhea, constipation | Nausea, headache, constipation |
| How it works | Mimics GLP-1 hormone to slow digestion and reduce appetite | Mimics GLP-1 and GIP hormones for enhanced appetite and metabolic control | Stimulates norepinephrine release to suppress appetite | Mimics GLP-1 hormone to reduce appetite (shorter-acting, daily) | Blocks food reward pathways (naltrexone) + reduces appetite (bupropion) |
| Best for | Patients seeking strong, sustained weight loss with broad insurance coverage | Patients seeking maximum weight loss; growing insurance coverage | Affordable first step, step therapy, or short-term jump-start | Insurance-favored formulary; patients who prefer daily GLP-1 dosing | Emotional or reward-driven eaters; patients who prefer oral medication |
| Can combine with | Phentermine (under supervision) | Phentermine (under supervision) | Wegovy or Zepbound (under supervision) | Phentermine (under supervision) | Not typically combined |
| Learn more | Wegovy at PEAK → | Zepbound at PEAK → | Phentermine at PEAK → | Saxenda at PEAK → | Contrave at PEAK → |
Costs reflect typical ranges. Your actual cost depends on your insurance plan. PEAK verifies coverage before prescribing.
Medication summaries
Each medication works through a different mechanism and is suited to different patient profiles. Here's a brief overview of each option.
Wegovy
Wegovy was the first GLP-1 medication FDA-approved specifically for weight loss. It mimics a natural hormone that signals fullness after eating, slows stomach emptying, and reduces appetite at the brain level. The STEP 1 trial demonstrated approximately 15% average body weight loss over 68 weeks.
Full Wegovy guideZepbound
Zepbound is the newest and most potent weight loss medication available. It activates both GLP-1 and GIP receptors, providing a dual mechanism that produces the highest average weight loss in clinical trials (18–22.5% of body weight). SURMOUNT trials showed approximately one in three patients lost 25% or more of their body weight.
Full Zepbound guidePhentermine
Phentermine is the most-prescribed weight loss medication in the United States and has been FDA-approved since 1959. It works as a sympathomimetic amine, stimulating norepinephrine release to suppress appetite. At low monthly generic pricing, it's the most affordable option and is commonly used as a first-line treatment or as part of step therapy before GLP-1 approval.
Full phentermine guideSaxenda
Saxenda is the first-generation GLP-1 approved for weight loss, with the longest track record of any GLP-1 weight management medication (FDA-approved 2014). Liraglutide mimics the GLP-1 hormone to reduce appetite and promote satiety. Daily dosing and a shorter half-life mean side effects resolve more quickly. Average weight loss of 8% in the SCALE trials.
Full Saxenda guideContrave
Contrave combines two medications that target different aspects of appetite. Naltrexone blocks the brain's opioid reward pathway for food, reducing cravings and the emotional pull of comfort eating. Bupropion is an antidepressant that also reduces appetite and increases energy. It's particularly effective for patients whose eating is driven by emotion, stress, or reward-seeking behavior. Contrave carries FDA boxed warnings for suicidal thoughts and behaviors and increased seizure risk.
Full Contrave guideHow to choose the right medication
There's no single "best" weight loss medication. The right choice depends on your individual situation. Here's how your PEAK clinician thinks about medication selection:
If maximum weight loss is the goal
Zepbound produces the highest average weight loss in clinical trials, followed by Wegovy. Both are injectable GLP-1 medications that require slow dose titration over 4–5 months. If your insurance covers one or both, these are typically the first recommendation for patients with a BMI of 30 or higher.
If cost is the primary concern
Phentermine is dramatically more affordable than any other option at low monthly generic pricing out of pocket. While the average weight loss is more modest (5–10%), it's an effective and accessible starting point, especially for patients without GLP-1 insurance coverage.
If emotional eating is a factor
Contrave specifically targets the brain's reward pathways and emotional eating patterns. If you find yourself eating when stressed, bored, or emotional rather than hungry, Contrave may be more effective than appetite-focused medications alone.
If you want a GLP-1 but prefer daily dosing
Saxenda offers the benefits of GLP-1 therapy with a daily injection instead of weekly. Its shorter half-life means side effects tend to resolve within hours, not days. It's also a strong option when insurance covers liraglutide but not semaglutide or tirzepatide.
If you strongly prefer oral medication
Phentermine and Contrave are both oral medications. Phentermine is a once-daily tablet; Contrave is taken twice daily. If self-injection is a barrier, these are your FDA-approved options.
If your insurance requires step therapy
Many insurers require a documented trial of a less expensive medication before approving a GLP-1. Phentermine is the most common step therapy requirement. PEAK manages this process, documenting your response so that when you reapply for Wegovy or Zepbound, the clinical justification is ready.
Unlike clinics that only prescribe one type of medication, PEAK offers all five FDA-approved options. If your first medication isn't the right fit — due to side effects, cost, insurance, or response — your clinician can adjust your treatment plan without referring you elsewhere. Many patients try more than one medication before finding their best match.
Can medications be combined?
In some cases, yes. The most common combination at PEAK is phentermine plus a GLP-1 medication (Wegovy or Zepbound). This approach provides immediate appetite suppression from phentermine while the GLP-1 titrates to its full therapeutic dose over several months.
Combination therapy is always determined by your clinician based on your specific medical history and response to treatment. Not all combinations are safe — for example, two GLP-1 medications should never be taken together, and Contrave has interactions that must be carefully managed.
Frequently asked questions
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In clinical trials, Zepbound (tirzepatide) produced the highest average weight loss at 18–22.5% of body weight, followed by Wegovy at approximately 15%. Phentermine and Contrave typically produce approximately 5–6%. However, the most effective medication is the one you can access, afford, and tolerate consistently. A medication that keeps you on track long-term will produce better results than a theoretically stronger option you can't stay on.
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Phentermine is by far the most affordable at low monthly generic pricing as a generic. Contrave ranges from moderate monthly out-of-pocket pricing. Wegovy and Zepbound can be high without insurance, but often cost low monthly copays for eligible commercially insured patients with coverage. PEAK verifies your insurance before recommending a medication so you know your cost upfront.
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Some combinations are used under medical supervision. The most common is phentermine plus a GLP-1 (Wegovy or Zepbound). However, not all combinations are safe. Two GLP-1 medications should never be taken together. Your PEAK clinician determines if combination therapy is appropriate based on your medical history and treatment response.
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The right medication depends on your BMI, weight loss goals, insurance coverage, budget, medical history, and personal preferences (injection vs. pill, emotional eating patterns, etc.). At PEAK, your clinician evaluates all of these during your first visit and recommends a personalized plan. Many patients try more than one medication before finding their best fit — that's normal and expected.
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Coverage varies by plan and medication. Phentermine is covered by most plans. Wegovy has broad GLP-1 coverage. Zepbound coverage is expanding. Contrave is covered by many plans. PEAK verifies your specific coverage before your first appointment so you know your cost before starting treatment.
Boxed warning — thyroid C-cell tumors: GLP-1 receptor agonists (semaglutide, tirzepatide, liraglutide) carry an FDA boxed warning for thyroid C-cell tumors observed in rodent studies. They are contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN2). Tell your provider immediately if you notice a lump in your neck, difficulty swallowing, or persistent hoarseness.
Boxed warning — Contrave (naltrexone/bupropion): Contrave carries an FDA boxed warning for suicidal thoughts and behaviors associated with the bupropion component. Patients should be monitored for neuropsychiatric symptoms, especially during early treatment. Contrave also increases seizure risk and should not be used with excessive alcohol consumption or abrupt discontinuation of alcohol, benzodiazepines, or antiepileptics.
References
- Wilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med. 2021;384(11):989-1002.
- Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med. 2022;387(3):205-216.
- Pi-Sunyer X, et al. A randomized, controlled trial of 3.0 mg of liraglutide in weight management (SCALE). N Engl J Med. 2015;373(1):11-22.
- Greenway FL, et al. Effect of naltrexone plus bupropion on weight loss in overweight and obese adults (COR-I). Lancet. 2010;376(9741):595-605.
- Zepbound (tirzepatide) prescribing information. FDA/Eli Lilly. NDA 217806.
- Wegovy (semaglutide) prescribing information. FDA/Novo Nordisk. BLA 215256.
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