Three tiers of evidence
You can take a prescription medicine, the one approved over-the-counter drug (orlistat), or a supplement. The evidence is strongest for prescriptions and weakest for supplements.
| Tier | Examples | What the evidence shows |
|---|---|---|
| Prescription | Zepbound, Wegovy, Wegovy pill, Saxenda, Qsymia, Contrave, phentermine, orlistat 120 mg | Average losses from a few percent to about 21% in large trials |
| Over the counter | Orlistat 60 mg (Alli) | Modest extra loss when paired with a lower-fat diet |
| Supplements | Berberine, green tea extract, fiber, apple cider vinegar | Small, mixed or no effect in most studies; not FDA-approved |
Your prescription options
If you meet the label criteria (usually BMI 30+, or 27+ with a weight-related condition), prescription medicines are the most effective tools available. GLP-1 medicines lead: see which GLP-1 is best and the strongest pills.
For a sense of scale: in its main trial, people on Wegovy lost 14.9% of their weight on average over 68 weeks, compared with 2.4% on placebo. For someone at 200 lb, that's about 30 lb. Older pills like Qsymia and Contrave averaged less but still help some people, especially those who can't take a GLP-1.
Prescription medicines also come with a clinician who checks your progress and side effects, which is part of what makes them safer than shopping on your own.
The one over-the-counter drug
Orlistat 60 mg blocks some of the fat you eat from being absorbed. It works best with meals that are lower in fat, because high-fat meals can cause oily, urgent stools. It can also lower absorption of some vitamins, so the label suggests a daily multivitamin taken at a different time.
How much does it help? In a 4-year trial of prescription-strength orlistat (120 mg), people lost about 3 kg (around 6 lb) more than people on placebo, on average, alongside a diet and activity program. The 60 mg over-the-counter version is half that strength. It's a modest tool, and it can interact with some medicines, so ask a pharmacist before you start.
Be wary of anything sold as an "over-the-counter GLP-1". There isn't one: here's why.
What supplements really do
Supplements don't need FDA approval before they're sold, and most weight-loss claims haven't held up in good trials. The FDA has also found hidden prescription drugs in some products marketed for weight loss. Read the evidence on specific ones: supplements, berberine and green tea.
Popular supplements by the evidence
| Supplement | What studies suggest | Watch out for |
|---|---|---|
| Fiber (psyllium, glucomannan) | May help fullness; weight effect small and mixed | Bloating; take with plenty of water |
| Green tea extract | Small effect at best in most trials | Rare reports of liver injury with concentrated extracts |
| Berberine | Small, short studies; modest effect | Stomach upset; can interact with other medicines |
| Apple cider vinegar | Very few, small studies | Can harm tooth enamel and the throat if taken undiluted |
Evidence grade: low for all of these. Small effects in small studies often shrink in bigger, better trials. More: apple cider vinegar.
Red flags on a product label
- Promises of fast loss, like 10 lb in a week, or "no diet needed".
- Words like "natural Ozempic", "drug-free GLP-1" or "works like a prescription".
- A "proprietary blend" that hides how much of each ingredient you get.
- Sold mainly through social media ads, with countdown timers or pressure to buy now.
The FDA has found hidden drugs in some weight-loss products, including sibutramine, a prescription drug taken off the US market in 2010 over heart risks. When in doubt, ask a pharmacist before you take it.
A simple way to start
- Check your BMI with the BMI calculator to see whether prescription options may apply to you.
- Find your daily calorie needs with the TDEE calculator, then aim for a modest deficit with the calorie deficit calculator. Staying at or above about 1,200 calories a day for women and 1,500 for men is a safe floor unless a clinician is supervising you.
- Build meals around protein and vegetables: find your protein floor.
- Add steps you enjoy and protect your sleep.
- If you've tried this for a few months and want more help, talk with a licensed clinician about medicine.
When to talk to your doctor
- Before taking any weight-loss medicine or supplement, especially with other prescriptions.
- If you take blood thinners, thyroid medicine or seizure medicine (orlistat and some supplements interact).
- If you're pregnant or breastfeeding.
- If a product makes your heart race, causes chest pain or changes your mood.
Run your numbers
Keep reading
Common questions
What can I take to lose weight fast?
Prescription GLP-1 medicines produce the largest losses, but they work over months, not days. A licensed clinician can tell you if you qualify.
Is there an over-the-counter weight loss pill that works?
Orlistat 60 mg (Alli) is the only FDA-approved option. Its effect is modest and it works best with a lower-fat diet.
Do weight loss supplements work?
Most show small or no effects in good trials, and they aren't FDA-approved. Some have contained hidden drugs.
Sources
- NIDDK: prescription medications to treat overweight and obesity
- Orlistat prescribing information (FDA label on DailyMed)
- FDA: concerns with unapproved GLP-1 drugs used for weight loss
- Jastreboff et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). NEJM 2022
- Wilding et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). NEJM 2021
Clinician review pending. Drafted from primary sources and waiting for sign-off by a licensed clinician (MD, DO or PharmD) before launch. Every number is checked against its source. Drug facts are re-checked quarterly, prices monthly and whenever a label changes. How we review · Report an error