Supplements and trends: questions and answers

Most don't work well. The NIH Office of Dietary Supplements reviewed common weight-loss ingredients and found little good evidence for most, with the better-studied ones showing small effects in short trials, often a pound or two.

Compare that with a steady 500-calorie daily deficit, which adds up to roughly a pound a week at first, or FDA-approved medicines with large trial results. Some supplements also carry real risks. Read our overview of supplements for weight loss before you buy.

No. The FDA doesn't approve dietary supplements before they're sold, and makers don't have to prove a product works. Companies are responsible for safety and truthful labels, and the FDA usually acts only after problems appear.

A label saying "FDA registered" or "made in an FDA-registered facility" doesn't mean the product was reviewed or approved. Third-party seals such as USP Verified or NSF Certified check that the bottle contains what the label says, though not that it causes weight loss.

A little, at most. Small, short trials, mostly in people with type 2 diabetes or metabolic syndrome, suggest berberine may lower weight by a few pounds on average, along with a modest drop in blood sugar. Study quality varies widely.

Stomach upset is common, and berberine can interact with diabetes medicines and other drugs processed by the liver. It isn't considered safe during pregnancy or breastfeeding. Ask your pharmacist before trying it. More detail in berberine for weight loss.

No. The nickname comes from berberine's modest effect on blood sugar, but it works differently from GLP-1 medicines and the results aren't close.

Berberine trials report a few pounds of loss on average. In the main trials for semaglutide and tirzepatide at weight-management doses, average losses were about 15% to 21% of body weight. Berberine also hasn't gone through FDA review for safety, dose or quality. If you're interested in GLP-1 treatment, start with who qualifies for a GLP-1.

The effect, if any, appears small. In one often-cited 12-week trial from Japan, people who drank vinegar daily lost about 1 to 2 kilograms more than a placebo group. Few other trials are of high quality.

Undiluted vinegar can damage tooth enamel and irritate the throat, so dilute it in water if you try it. People with reflux, kidney disease or who take insulin or diuretics should check with a clinician first. See apple cider vinegar and weight loss.

Only slightly, if at all. A Cochrane review found green tea preparations produced a small weight loss that was likely not clinically important.

Brewed green tea is a fine drink. Concentrated green tea extract in pills is different: it has been linked to rare cases of liver injury, especially when taken on an empty stomach. Stop and see a clinician if you notice yellow skin or eyes, dark urine or belly pain. Read more on green tea and weight loss.

They may help a little with fullness, but evidence for weight loss is mixed. Glucomannan, a popular fiber pill, has shown inconsistent results, and psyllium is better known for helping digestion and cholesterol than weight.

Fiber from food, like beans, oats, vegetables and fruit, brings more benefits. If you use a fiber supplement, take it with plenty of water, since some fibers swell and can pose a choking or blockage risk. Separate it from medicines by a couple of hours, as fiber can affect absorption.

Often a little, but it's mostly water inside the muscle, not fat. Many people gain about 1 to 3 pounds in the first weeks, especially with a loading phase.

Creatine is one of the most studied sports supplements and can help with strength training. It doesn't cause fat loss on its own. It's generally considered safe for healthy adults at common doses, but people with kidney disease should ask their clinician first. More detail in creatine and weight loss.

No supplement contains an FDA-approved GLP-1 medicine or matches its results. Products sold as "natural Ozempic," "herbal GLP-1" or "GLP-1 support" usually contain fiber, berberine, probiotics or plant extracts with small or unproven effects.

The phrase is a marketing hook, not a medical category. Some products sold online have also been found to contain hidden drugs. If you're curious about GLP-1 medicines, a licensed clinician can tell you whether you qualify. See what's actually available over the counter.

No. In the US, all FDA-approved GLP-1 medicines require a prescription. Any website offering semaglutide or tirzepatide without one, or with only a quick questionnaire and no licensed clinician involved, is a red flag.

Products sold "for research use only" or by sites with no licensed US pharmacy may contain the wrong ingredient, wrong dose or contaminants. The FDA has also found counterfeit Ozempic in the US supply. To check a pharmacy, look for a state license and ask your clinician.

Compounded GLP-1s are versions of semaglutide or tirzepatide mixed by a pharmacy rather than made by the brand manufacturer. They are not FDA-approved, and the FDA doesn't review them for safety, effectiveness or quality before they're sold.

The FDA has reported dosing errors with compounded products and warned that salt forms such as semaglutide sodium are not the ingredient in approved medicines. Compounding rules tightened after the FDA declared the shortages over. Read our compounded GLP-1 guide for the legal background.

There's no way to know, which is the problem. Peptides sold "for research use only, not for human consumption" aren't approved for people, and nobody checks them for the right ingredient, dose, sterility or contaminants.

The FDA has flagged safety concerns with several popular peptides, including BPC-157 and AOD-9604, when compounded. Injecting an unverified product can cause infections or dosing mistakes. If you've used one and feel unwell, contact a clinician. Read our explainer on peptides for weight loss.

Not legitimately. As of our last review, retatrutide is an investigational medicine still in clinical trials and isn't FDA-approved. The FDA has said it can't be used in compounding under federal law.

Anything sold online as retatrutide is unapproved and unverified, so it may contain the wrong substance, the wrong amount or contaminants. The only legitimate way to get it before approval is through a clinical trial. Follow its status on our retatrutide page.

No. Any quick drop on the scale is mostly water and stool, not fat. Many detox and "skinny" teas contain senna or other stimulant laxatives, and some contain diuretics or large amounts of caffeine.

Your liver and kidneys already handle detoxing. Regular use of laxative teas can cause cramps, diarrhea, dehydration and electrolyte problems. The FTC has acted against tea marketers for unsupported weight-loss claims. If a tea promises to flush fat or melt pounds, treat it as a red flag.

No, and using them for weight loss can be dangerous. Laxatives act on the large intestine, after most calories have already been absorbed. The scale drops because you lose water, which returns when you eat and drink normally.

Misuse can cause dehydration, electrolyte problems that affect the heart, and dependence. Laxative misuse for weight control can also be a sign of an eating disorder, and help is available. If you feel faint, have a racing or irregular heartbeat or severe weakness, call 911. See laxatives and weight loss.

It can, mainly because it cuts out many foods and helps some people eat less. Early loss on keto is often rapid, but much of that first drop is water from depleted glycogen.

Over longer periods, trials generally find low-carb and other diets produce similar weight loss when calories are matched. Keto works best for people who find it easy to follow. Many find it hard to keep for months, and weight often returns when carbs come back without a plan.

For many healthy adults, a short-term keto diet is reasonably safe, but it isn't right for everyone. Common early side effects include tiredness, headache, constipation and bad breath, sometimes called the "keto flu."

LDL cholesterol rises in some people. People taking insulin, sulfonylureas or SGLT2 inhibitors, and those with kidney, liver or pancreas conditions, should talk to a clinician first, since medicine changes or monitoring may be needed. Pregnant people and anyone with an eating-disorder history should also get advice before starting.

It works about as well as regular calorie cutting, not better. In a 12-month trial published in NEJM in 2022, people eating within an 8-hour window lost about the same amount as people cutting the same calories without a time limit.

Fasting mostly helps by making it easier to eat less, so it can suit people who find a clear stop time easier than counting. It's less suitable for people with diabetes on certain medicines, pregnant people or anyone with an eating-disorder history. Plan a window with the intermittent fasting calculator.

For most healthy adults, a 16:8 schedule, eating within 8 hours and fasting for 16, is generally considered safe. Water, black coffee and plain tea are usually fine during the fast.

Talk to a clinician first if you have diabetes, especially on insulin or a sulfonylurea, since fasting can cause low blood sugar. The same applies if you're pregnant, breastfeeding, under 18 or have a history of eating disorders. Make sure your meals still include enough protein and fiber. See how a 16:8 schedule fits a typical day.

No studies show it does. The viral drink mixes pink Himalayan salt with water and sometimes lemon, and its main effect is adding sodium to your day.

Pink salt is mostly sodium chloride, its trace minerals are tiny, and it usually lacks the iodine added to table salt. A quarter teaspoon of salt has about 575 mg of sodium, a quarter of the 2,300 mg daily limit for most adults. People with high blood pressure, heart or kidney disease should skip it. See the pink salt trick.

It may help a little with fullness before a meal, but there's no evidence it causes meaningful weight loss on its own. The trend involves drinking or eating unflavored gelatin, which has about 25 calories per packet.

Gelatin adds a small amount of protein, but it's an incomplete protein and shouldn't replace protein-rich foods at meals. A glass of water, a broth-based soup or a high-fiber snack before meals can serve the same purpose. Read more on the gelatin trick.

There's no good evidence they do, and no weight-loss patch is FDA-approved. Many are sold as supplements with ingredients like green tea, garcinia or "GLP-1 support" blends.

The FTC lists claims that wearing a product or rubbing it on the skin will cause substantial weight loss among the claims that are almost always false. Patches can also irritate the skin. Your money is better spent on things with evidence, like a good pair of walking shoes. See weight-loss patches.

Most fat burners rely on caffeine or other stimulants, which may cause a small, short-term increase in calorie burn. That effect is too small to drive meaningful weight loss on its own.

Stimulant blends can cause a racing heart, jitters, anxiety, high blood pressure and poor sleep, and caffeine totals can be much higher than they look. The FDA has found hidden drugs in some products. People with heart conditions, high blood pressure or anxiety should avoid them. Chest pain or fainting after taking one means call 911.

Yes. The FDA has found hidden prescription drugs and banned ingredients in hundreds of products marketed for weight loss, often sold online or through social media.

Examples include sibutramine, a weight-loss drug removed from the US market over heart risks, and laxatives or diuretics not listed on the label. These can cause serious harm, especially with other medicines. Before buying, search the FDA's tainted weight-loss products list, and be wary of products promising fast results or claiming to work like a prescription drug.

The FTC's "Gut Check" guide lists claims that are almost always false. They include promises of 2 or more pounds a week for a month without diet or exercise, substantial loss no matter what you eat, permanent results after you stop the product, and safe loss of more than 3 pounds a week for over a month.

Other red flags: blocking fat or calorie absorption for big losses, results for everyone, and weight loss from something you wear or rub on your skin. Before-and-after photos and influencer codes aren't evidence either.

Be cautious. Viral tips often spread because they're simple and surprising, not because they're tested. Personal stories can be real but rarely show what would happen for most people.

Influencers may also be paid to promote products, and the FTC requires them to disclose that clearly. Before trying a trend, ask: is there a trial behind it, does it promise fast or effortless results, and is someone selling something? For any product that could affect your health or medicines, check with a pharmacist or clinician.

Not directly. Lemon water doesn't burn fat or detox your body. It can help, though, if it replaces sugary drinks like soda or juice, saving calories every day.

Drinking water before meals may also help some people feel fuller. If plain water feels boring, lemon is an easy, low-calorie way to drink more. The acid can wear tooth enamel over time, so rinse with plain water afterward. Read more on lemon water and weight loss.

Not unless you're low in B12. There's no good evidence that B12 shots or pills cause weight loss in people with normal levels. Correcting a true deficiency can ease tiredness, which may make activity easier.

People more likely to be low include those taking metformin long term, adults over 50, people on a vegan diet without supplements and people who've had weight-loss surgery. A blood test can tell. "Lipo" shots that mix B12 with other ingredients haven't been shown to burn fat. See B12 and weight loss.

Yes, one. Lower-strength orlistat is FDA-approved for over-the-counter use in adults with overweight, alongside a reduced-calorie, low-fat diet. It's a medicine, not a supplement, and blocks some dietary fat from being absorbed.

Its added weight loss in trials was modest. Common side effects include gas with oily spotting and urgent bowel movements, especially after fatty meals. The label advises a daily multivitamin. Ask a pharmacist first if you take blood thinners, thyroid medicine or cyclosporine. Compare options in what can I take to lose weight.

Stop taking it and contact a clinician or pharmacist, and bring the bottle with you. For chest pain, trouble breathing, fainting, a seizure or signs of a severe allergic reaction, call 911. For a possible overdose or poisoning question, call Poison Control at 1-800-222-1222.

Yellow skin or eyes, dark urine or belly pain can signal liver injury and need prompt care. You can also report problems to the FDA through its MedWatch program, which helps the agency spot unsafe products.