Several prescription drug families are approved in the United States for long term weight management, and they do not perform alike. One is a capsule that blocks fat absorption in the gut. Two are weekly injections that turn down appetite signalling in the brain. The distance between them, measured in pounds lost, monthly cost and side effects, is wide enough that the word best means nothing until you say what you are optimising for.
Most people start this search wanting weight loss pills that actually work, then discover three inconvenient facts: the strongest results now come from injections rather than tablets, the cheapest options are decades-old generics, and your real price depends less on the drug than on whether a plan will pay for it. This guide walks those trade-offs in order, then shows how to pressure test one program before you hand over a card.
First, decide what you are optimising for
Every comparison below flips depending on which of these matters most to you. Pick a first priority and a second before you read on.
- Total weight lost. The dual-agonist and GLP-1 injections lead here by a wide margin over any oral drug.
- Cash price. Generic phentermine and generic orlistat sit at the bottom of the price ladder. Branded injections sit at the top.
- Coverage odds. Some plans exclude weight loss drugs outright but cover the same molecule for type 2 diabetes, sleep apnea or cardiovascular risk.
- Route and routine. A weekly self-injection suits some people. A daily tablet suits others. Neither is more serious than the other.
- Tolerability. Nausea, stimulant effects, cognitive fog and oily stools are different problems. You will tolerate one better than another.
- Speed. Telehealth intake can move fast; prior authorization and step therapy can add weeks.
If you are not sure which of those is your bottleneck, answer three questions and get routed to the right comparison instead of reading all of them.
Step 1 of 3
What do you need help with?
Step 2 of 3
How will you pay?
Step 3 of 3
What matters most?
Your starting point
Every list is ranked by the same public formula - nothing here can be bought.
The approved drugs, and what each one does
Approved obesity medicines fall into three practical groups. Knowing the group tells you more than the brand name does.
Weekly injections: the appetite pathway
Semaglutide (Wegovy) is a GLP-1 receptor agonist, meaning it copies a gut hormone that signals fullness and slows stomach emptying. It is dosed once a week and titrated up over several months. The same molecule is sold as Ozempic for type 2 diabetes and as Rybelsus in an oral tablet for diabetes, which is why search results mix them up constantly.
Tirzepatide (Zepbound) hits two receptors, GIP and GLP-1, and is also weekly. It is sold as Mounjaro for type 2 diabetes. Liraglutide (Saxenda) is an older daily GLP-1 injection, now available in generic form in some markets, which can make it the cheapest injectable route.
Daily tablets for long term use
Phentermine and topiramate (Qsymia) pairs an appetite suppressant with an anti-seizure drug that reduces cravings. Naltrexone and bupropion (Contrave) combines an opioid blocker with an antidepressant to act on reward and hunger circuits. Orlistat blocks roughly a third of dietary fat from being absorbed; it is sold as Xenical by prescription and as Alli at a lower strength without a prescription.
Short term stimulants
Phentermine alone (Adipex-P, Lomaira) is the oldest and most prescribed weight loss drug in the country. It is approved for short term use, commonly up to about 12 weeks, and it is cheap as a generic. Longer use happens in practice but is off label, so ask your prescriber to say plainly what the plan is after month three.
Newer oral GLP-1 agents keep moving through trials and regulatory review, so approval status changes. Check the current label rather than a news headline before assuming a pill version of an injection is available to you.
How much weight loss each drug actually delivers
Trial averages are the fairest way to rank these, with two caveats: everyone in those trials also got diet and activity counselling, and averages hide a wide spread. Some people lose far more than the average, and roughly one in ten responds poorly to any given agent.
Weight Loss by Drug Type: Trial Averages
| Drug | Average Body Weight Lost | |
|---|---|---|
| Tirzepatide 15mg (72 weeks) | Tirzepatide 15mg | ~20.9% |
| Semaglutide 2.4mg (68 weeks) | Semaglutide 2.4mg | ~14.9% |
| Phentermine + topiramate | Phentermine + topiramate | mid-high single digits |
| Naltrexone + bupropion | Naltrexone + bupropion | mid-high single digits |
| Orlistat | Orlistat | lowest of group |
The oral drugs land lower. Phentermine with topiramate and naltrexone with bupropion typically produce mid to high single digit percentage losses over a year, and orlistat lands lowest of the group. That still matters: losing 5% of body weight is the threshold most guidelines use for meaningful improvement in blood pressure, blood sugar and lipids.
Why it matters: a drug that costs a quarter as much and delivers 7% loss can beat a 20% drug you stop paying for in month three.
Best on clinical care
The quality of the medical side.
- Form Health8.7 / 10
- 9amHealth8.5 / 10
- Marek Health8.4 / 10
- Teladoc Health8.3 / 10
- Defy Medical8.2 / 10
Best on value
What you get for what you pay.
- Found8.9 / 10
- ShedRx8.2 / 10
- Henry Meds8.2 / 10
- Lumimeds8 / 10
- Amble8 / 10
Ranked from our own scores, recomputed as data changes. Providers cannot pay for a place.
What these drugs cost when you pay cash
Cash pricing is where the market is most confusing, because the same molecule can be quoted as a branded pen, a manufacturer self-pay vial, or a telehealth bundle that folds the clinician visit into the monthly number. Generic phentermine can run a few dollars a month at a retail pharmacy. Branded weekly injections are the other end of the scale entirely.
Across the semaglutide programs tracked here, monthly prices span from $99 to $499, with a median around $179 across 14 tracked prices.
Before you compare two monthly numbers, confirm they include the same things. Ask each program what happens to the price when your dose goes up, since that is where quoted introductory rates often break.
- The medication itself, at every dose step, not just the starting dose
- The clinician visit and any follow up visits
- Syringes and needles if the drug ships as a vial rather than a pen
- Lab work, if required before the first prescription
- Shipping, and whether cold chain handling is charged separately
- Cancellation terms, and whether you are locked into a multi-month plan
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Insurance mechanics that decide your real price
Coverage for obesity drugs is not a yes or no question. It is a sequence of gates, and each one has a workaround worth knowing.
- Formulary check. If the drug is excluded from your plan’s list, no amount of paperwork fixes it. Ask for the exclusion in writing, then look at cash routes.
- Prior authorization. Your prescriber submits BMI, weight history, related conditions and often documentation of a supervised diet attempt. Incomplete records are the usual reason for denial.
- Step therapy. Many plans require you to try a cheaper drug first, often phentermine or orlistat, before approving an injection.
- Deductible phase. Even with approval, you pay the full negotiated rate until the deductible is met. That first month can be a shock.
- Copay versus coinsurance. A flat copay is predictable. Coinsurance at 25% or 30% of a high list price is not, and it resets every plan year.
Manufacturer savings cards typically apply only to commercial insurance, not to Medicare, Medicaid or other federal coverage. Medicare Part D has long excluded drugs used solely for weight loss, though the same molecule may be covered when prescribed for type 2 diabetes or another approved indication. Ask your plan which indication is on the claim, because that single detail often decides the answer.
No provider matches that filter. .
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If you have partial coverage with a high deductible, run both routes side by side before committing to either.
Insurance or cash pay, which is cheaper
Going through insurance is not automatically cheaper. Deductibles, copays and prior authorisation can make a cash-pay programme the better deal.
Coverage is never something a programme can promise: plans decide, prior authorisation is routine for GLP-1 medicines, and denials are common. Confirm with your own plan before choosing.
Do you qualify? The thresholds prescribers use
Most approved obesity medicines share the same entry criteria for adults: a body mass index of 30 or higher, or 27 or higher with at least one weight related condition. Those conditions usually include high blood pressure, type 2 diabetes, high cholesterol or obstructive sleep apnea.
Extra indications can unlock coverage that plain weight loss will not. Some tirzepatide and semaglutide labels now include obstructive sleep apnea and cardiovascular risk reduction, and a documented diagnosis in your chart can change a denial into an approval. Bring the sleep study or the cardiology note to the appointment.
BMI calculator
Most weight-loss programmes screen on BMI before they will prescribe. This is the number they will use.
A screening number, not a diagnosis. It does not distinguish muscle from fat, and it reads high for muscular builds.
Side effects, warnings and who should avoid each drug
This is the section that decides whether you stay on treatment. Most people who quit do so because of side effects or price, not because the drug failed.
| Drug | Form | Common side effects | Key cautions |
|---|---|---|---|
| Semaglutide, tirzepatide, liraglutide | Injection | Nausea, vomiting, diarrhea, constipation, reflux, fatigue | Boxed warning for thyroid C-cell tumors seen in rodents; avoid with personal or family history of medullary thyroid carcinoma or MEN 2. Reports of pancreatitis, gallbladder disease and kidney injury from dehydration. |
| Phentermine and topiramate | Capsule | Tingling in hands and feet, dry mouth, taste changes, insomnia, word-finding trouble | Can cause birth defects, so pregnancy testing and contraception are required. Raises heart rate. Linked to kidney stones and metabolic acidosis. |
| Naltrexone and bupropion | Tablet | Nausea, constipation, headache, dizziness, dry mouth | Boxed warning for suicidal thoughts and behaviors. Lowers seizure threshold. Not for uncontrolled high blood pressure, seizure disorders, eating disorders, or anyone using opioids. |
| Orlistat | Capsule | Oily stools, gas with discharge, urgent bowel movements | Reduces absorption of fat soluble vitamins, so a multivitamin at bedtime is standard. Interacts with levothyroxine, warfarin and cyclosporine. |
| Phentermine alone | Tablet | Insomnia, dry mouth, restlessness, raised heart rate | Approved for short term use. Avoid with uncontrolled high blood pressure, heart disease, overactive thyroid, glaucoma, or recent MAOI use. |
Three practical points cut across all of them. Injectable GLP-1 drugs slow stomach emptying, so tell any anesthesiologist or endoscopy team that you take one. If you also take insulin or a sulfonylurea, low blood sugar becomes a real risk and doses usually need adjusting. And rapid weight loss on any drug costs muscle as well as fat, which is why protein intake and resistance training belong in the plan from week one.
Call your clinician promptly for severe abdominal pain that radiates to the back, persistent vomiting, signs of dehydration, a new lump in the neck, or any change in mood or thinking on naltrexone and bupropion.
Over the counter pills and supplements: what is real
The only weight loss drug approved for sale in the United States without a prescription is orlistat at the 60 mg strength, sold as Alli. Its effect is modest and its side effects are distinctive enough that many people stop.
Everything else on the shelf is a dietary supplement. Supplements are not reviewed for effectiveness before sale, and products marketed to women for belly fat have repeatedly been found to contain undeclared prescription drugs. Green tea extract, garcinia, raspberry ketone and similar ingredients have no evidence base comparable to the approved drugs above. There is also no drug, prescription or otherwise, that removes fat from one specific area of the body.
If cost is the reason you are looking at supplements, generic phentermine or generic orlistat will usually cost less than a branded fat burner and at least has trial data behind it.
How to ask your doctor for weight loss injections or pills
The conversation goes better when you bring evidence rather than a brand name. Prescribers approve requests they can document.
- Bring numbers. Your current weight, your highest weight, and BMI. Add blood pressure readings or recent labs if you have them.
- List what you have already tried. Name the programs, the dates and the results. Plans often require a documented diet attempt.
- Name your related conditions. Prediabetes, sleep apnea, fatty liver, high cholesterol and joint pain all strengthen the case.
- Say the goal in health terms. Lowering A1c or blood pressure lands better than a target dress size.
- Ask directly. A clear sentence works: I would like to discuss whether a prescription weight management medicine is appropriate for me.
- Ask about coverage before you leave. Which drug does my plan prefer, and will your office file the prior authorization?
If your primary care office does not prescribe these drugs, an obesity medicine specialist or a telehealth program can. Ask the telehealth service whether records go back to your regular doctor, because continuity matters once you are on a long term medicine.
Medicare, seniors, men and women over 60
The drugs work in older adults, but two issues need attention. Muscle loss carries more consequence after 60, so protein targets and strength training are not optional extras. And polypharmacy raises the odds of an interaction, particularly with blood pressure drugs, diabetes drugs and anything affecting the kidneys.
Coverage is the harder problem. Because Part D has historically excluded drugs used only for weight loss, seniors often end up paying cash or qualifying through a different diagnosis. If you have type 2 diabetes, cardiovascular disease or documented sleep apnea, that route is worth exploring with your prescriber first.
Men and women respond to the same drugs, and trial results do not split neatly by sex. What does differ is context: women of reproductive age must avoid phentermine with topiramate without reliable contraception, and anyone planning pregnancy should stop GLP-1 medicines well in advance, per the timing on the label.
How to sanity-check one provider before you commit
Once you have a shortlist, the remaining work is verification. We track 154 programs, and 58 of them carry semaglutide, so quality varies widely. Run this check on the one you are close to choosing.
Before You Commit to a Provider: What to Verify
- Is there a named, licensed clinician who reviews and signs the prescription?
- Is the medication branded/manufacturer-supplied or compounded, and which pharmacy fills it?
- What is the price at the maintenance dose, not just the starting dose?
- Can you cancel monthly, and what happens to prepaid months if you stop?
- Is there between-visit support for dose escalation and side effects?
- Will they send records to your primary care doctor?
- Is there a licensed clinician review before a prescription, with a named prescriber you can identify?
- Is the medication a branded or manufacturer-supplied product, or a compounded preparation? Ask which, and ask which pharmacy fills it.
- What is the price at the maintenance dose, not the starting dose?
- Can you cancel monthly, and what happens to prepaid months if you stop?
- Is there support between visits for dose escalation and side effects, and how fast do they answer?
- Will they send records to your primary care doctor?
Red flags are consistent across the sector: no clinician interaction at all, prices that only appear after payment details are entered, pressure to buy six months up front, guaranteed pound-per-week claims, and vague answers about the sourcing pharmacy. Any one of those is reason enough to move on.
Best on trust and safety
Certification, prescribing and transparency.
- Form Health8.6 / 10
- Levity8.5 / 10
- Willow8.2 / 10
- Allara Health8.2 / 10
- Noom Med8.2 / 10
Best on support
What happens when something goes wrong.
- Amazon One Medical7.5 / 10
- Found7.5 / 10
- FuturHealth7.4 / 10
- Form Health7 / 10
- Marek Health7 / 10
Ranked from our own scores, recomputed as data changes. Providers cannot pay for a place.
Quick tip: screenshot the full price schedule at every dose step on the day you sign up, so you have a reference if the monthly charge changes.
Sources
- National Institute of Diabetes and Digestive and Kidney Diseases: prescription medications to treat overweight and obesity
- Peer-reviewed trial report: once-weekly semaglutide in adults with overweight or obesity
- Peer-reviewed trial report: tirzepatide once weekly for the treatment of obesity
This content is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified clinician or pharmacist about your situation, and seek urgent care or call your local emergency number for severe or worsening symptoms.