Guide: the evidence
Do Weight Loss Supplements Work? What the Reviews of Weight Loss Pills Found
Weight loss supplements work far less than their ads suggest. The NIH says there is little scientific evidence that they work. A review of 315 trials found most showed no weight loss, and the best positive trials ranged from 0.3 to 4.93 kg. No study has tested SodaSlim, a capsule with 138 mg of caffeine.
Written by the SodaSlim label deskUpdated
The short answer01
Do weight loss supplements work?
Do weight loss supplements work? Rarely, and not by much. The NIH puts it plainly: "there's little scientific evidence that weight-loss supplements work" (NIH ODS, Weight loss supplements (consumers)).
The biggest check we found is a 2021 review of 315 randomized trials. Most of them showed no weight loss. Only 16 of the 52 well-run trials found a real difference from placebo, and those differences ran from 0.3 to 4.93 kg (UNC / Obesity 2021, Review of weight-loss supplements). That is the best case, not the average case.
The NIH also notes that many studies are small, short or poorly designed, and that products mix several ingredients, which makes it hard to know what did what (NIH ODS, Dietary Supplements for Weight Loss (health professionals)). So weight loss pills evidence is thin, and what exists is modest.
| Ingredient | What reviews found | How to read it |
|---|---|---|
| Green tea extract | Outside Japan, -0.04 kg versus placebo (Cochrane, Green tea for weight loss (Jurgens)) | Not significant; the authors call any loss unlikely to matter |
| Garcinia (HCA) | -0.88 kg versus placebo (Onakpoya 2011, Garcinia (HCA) meta-analysis) | Small, borderline; the NIH consumer sheet says little to no effect (NIH ODS, Weight loss supplements (consumers)) |
| Green coffee extract | Three trials, all high risk of bias (Onakpoya 2011, Green coffee extract meta-analysis) | Poor quality; treat as unproven |
| Raspberry ketone | Reliable human research is lacking (Rao 2021, Raspberry ketone review) | Effect on weight unknown |
| Caffeine | A small rise in lab markers, not in body weight (Meta-analysis, Does caffeine increase fat metabolism?) | A stimulant, not a proven weight tool |
Why ads sound better02
Why do weight loss pills sound better than the studies?
Ads quote the best result and skip the average. A single small trial, a rodent study or one happy customer can fill a whole sales page.
The FTC says research on an ingredient does not automatically back a finished product. The dose, the formula and the mix must match what was tested. It also says testimonials are not proof, and that a large-loss story can mislead when a good trial shows a much smaller average gain over placebo (FTC, Health Products Compliance Guidance).
The FTC has also listed claims that sound too good to be true: losing 2 or more pounds a week for a month without diet or exercise, loss no matter what you eat, permanent loss after you stop, and blocking fat or calorie absorption (FTC, Seven red flags for bogus weight-loss claims).
One ingredient, one trial
A result for green tea alone says little about a capsule with five lines in it.
Averages hide in the fine print
"Up to" numbers come from the best trial. The pooled averages in the table are about a kilogram or less.
Stories are not trials
A testimonial shows one person. Only a controlled trial can compare against placebo.
Safety03
Are weight loss supplements safe to try?
Not automatically. "Natural" does not mean safe, and supplements are not approved by the FDA before they are sold (NCCIH, Weight Control and Dietary Supplements) (FDA, Questions and answers on dietary supplements).
The NIH advises talking to a provider first, especially with high blood pressure, diabetes, heart disease or liver disease (NIH ODS, Weight loss supplements (consumers)). Side effects are most likely at high doses or when several supplements are combined (NIH ODS, Dietary Supplements: What You Need to Know).
Some weight loss products sold online have been found to hold hidden prescription drugs. The FDA warns that its public list covers only a small fraction of them, so a product missing from the list is not proven clean (FDA, Tainted weight loss products). Nothing we found says SodaSlim contains such a drug; this is background for any shopper.
A supplement is not a medicine. Never stop or change a prescribed medicine because you started one. Tell your doctor and pharmacist about everything you take. Chest pain, fainting, a racing heartbeat that will not settle, dark urine or yellow skin or eyes need care now.
SodaSlim: 30 capsules, 30-day bottle1 capsule a day · 2, 3 or 6 bottles · price and guarantee terms at checkout
See packsWhere SodaSlim fits04
What does this mean for a capsule like SodaSlim?
SodaSlim is a capsule, not a drink, and no study has tested it. Its five printed lines are the same kinds of ingredients the reviews above cover, so the same cautious reading applies.
The label prints 138 mg of caffeine anhydrous, 130 mg each of green tea extract, green coffee bean extract, garcinia extract and raspberry ketone, one capsule a day. Caffeine alone is 34.5% of the FDA's 400 mg a day guide for most healthy adults (FDA, Spilling the beans: how much caffeine is too much). The label front uses support phrases ending in an asterisk, which lead to the FDA statement that the claims have not been evaluated.
The bars below compare the label amounts with reference figures sources give. They are limits and warning levels, not proven doses, so a short bar is not a promise of an effect.
For garcinia and raspberry ketone we found no verified daily study dose, so no bar is drawn. Read each line on the ingredients page, and the claims one by one on the benefits page.
What has evidence05
What does evidence-based weight management look like?
Evidence-based care is eating, activity and, when needed, a provider's program. A supplement is not part of those pages.
Mayo Clinic and the CDC describe a gradual pace of 1 to 2 pounds a week over the long term as the one more likely to last (Mayo Clinic, Weight loss: 6 strategies for success) (CDC, Steps for losing weight). NIDDK suggests a first goal of 5% to 10% of starting weight within six months (NIDDK, Choosing a safe and successful weight-loss program).
- A gradual paceMayo Clinic and the CDC describe 1 to 2 pounds (0.5 to 1 kg) a week over the long term as the pace more likely to last. (Mayo Clinic, Weight loss: 6 strategies for success) (CDC, Steps for losing weight)
- A first goalNIDDK suggests 5% to 10% of starting weight over six months; another page says 5% over six months may be a good first goal. (NIDDK, Choosing a safe and successful weight-loss program) (NIDDK, Treatment for overweight and obesity)
- Standard careDiet, activity and, when needed, a provider's program, prescription medicine, surgery or devices. Supplements are not part of those pages. (CDC, Steps for losing weight) (NIDDK, Treatment for overweight and obesity)
- A choice of programBe wary of promises such as 'lose 30 pounds in 30 days' or loss without diet or exercise. (NIDDK, Choosing a safe and successful weight-loss program) (FTC, Seven red flags for bogus weight-loss claims)
If you still want to try a capsule, ask your doctor or pharmacist first. The fat burner safety guide covers the warning signs, and the guides hub lists the rest.
FAQ06
SodaSlim questions people ask
What do weight loss pills do according to the NIH?
The NIH says there is little scientific evidence that weight-loss supplements work. Some ingredients show small average differences, and studies are often small and short (NIH ODS, Weight loss supplements (consumers)). It advises talking to a provider before starting any of them.
How much weight can you lose with supplements?
On average, about a kilogram or less in the better-quality reviews of green tea and garcinia (Cochrane, Green tea for weight loss (Jurgens)) (Onakpoya 2011, Garcinia (HCA) meta-analysis). The best low-risk trials in a 315-trial review ranged from 0.3 to 4.93 kg (UNC / Obesity 2021, Review of weight-loss supplements). Those are averages for study groups, not promises for you.
Are over the counter weight loss supplements regulated?
Loosely. The FDA does not approve supplements before sale. It acts after products reach the market, and the maker must hold support for its claims (FDA, Questions and answers on dietary supplements). That is why the label carries a statement that claims were not evaluated by the FDA.
Why do some studies show weight loss and others do not?
Trials differ in size, length, dose and quality. Small or poorly designed trials tend to look better, and the NIH notes many are exactly that (NIH ODS, Dietary Supplements for Weight Loss (health professionals)). Well-run trials usually report smaller differences.
Does a supplement work without diet and exercise?
No source we found shows that. Standard care is eating, activity and, when needed, a provider's program (NIDDK, Treatment for overweight and obesity). The FTC lists loss with no diet or exercise as a red flag (FTC, Seven red flags for bogus weight-loss claims).
Can a weight loss supplement hide a drug?
It can happen. The FDA has found weight loss products holding drugs not on the label, such as sibutramine, which was pulled from the market in 2010 (FDA, Public notification: Body Shape Weight Loss System). Nothing we found says SodaSlim contains one.
Should I ask my doctor before taking a weight loss capsule?
Yes. Ask first, especially with a heart, liver, thyroid or blood pressure condition, diabetes, pregnancy or any regular medicine (NIH ODS, Weight loss supplements (consumers)). Keep taking prescribed medicine as directed.
Sources (22)
- Spilling the Beans: How Much Caffeine Is Too Much?U.S. Food and Drug Administration, 2024
- Dietary Supplements for Weight Loss: Fact Sheet for Health ProfessionalsNIH Office of Dietary Supplements, 2026
- Dietary Supplements for Weight Loss: Fact Sheet for ConsumersNIH Office of Dietary Supplements, 2021
- Weight ControlNational Center for Complementary and Integrative Health, 2017
- Review shows minimal high-quality evidence dietary supplements lead to weight lossUNC Health / UNC School of Medicine (study by J. Batsis, Obesity journal), 2021
- Green TeaMemorial Sloan Kettering Cancer Center, 2026
- Green tea for weight loss and weight maintenance in overweight or obese adultsCochrane (Jurgens TM et al.), 2021
- EFSA assesses safety of green tea catechinsInstitute of Food Science and Technology (summary of EFSA opinion), 2018
- The Use of Garcinia Extract (Hydroxycitric Acid) as a Weight loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical TrialsOnakpoya I, Hung SK, Perry R, Wider B, Ernst E, Journal of Obesity, 2011
- The Use of Green Coffee Extract as a Weight Loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical TrialsOnakpoya I, Terry R, Ernst E, Gastroenterology Research and Practice, 2011
- Pharmacological Exploration of Phenolic Compound: Raspberry Ketone (Update 2020)Rao S, Kurakula M, et al., Plants, 2021
- Does caffeine increase fat metabolism? A systematic review and meta-analysisInternational Journal of Sport Nutrition and Exercise Metabolism (authors not shown on the record read), 2023
- FTC Stops Bogus Ads for "Bio Trim" and Other Weight-loss ProductsFederal Trade Commission, 2005
- Weight loss: 6 strategies for successMayo Clinic, 2024
- Steps for Losing WeightCenters for Disease Control and Prevention, 2025
- Choosing a Safe & Successful Weight-loss ProgramNational Institute of Diabetes and Digestive and Kidney Diseases, 2024
- Treatment for Overweight & ObesityNational Institute of Diabetes and Digestive and Kidney Diseases, 2023
- Tainted Weight Loss ProductsU.S. Food and Drug Administration, 2026
- Public Notification: Body Shape Weight Loss System Contains Hidden Drug IngredientsU.S. Food and Drug Administration, 2024
- Questions and Answers on Dietary SupplementsU.S. Food and Drug Administration, 2026
- Dietary Supplements: What You Need to KnowNIH Office of Dietary Supplements, 2023
- Health Products Compliance GuidanceFederal Trade Commission, 2022
Who wrote this07
Written and reviewed by
Pages built from the label, the seller’s materials and linked NIH, FDA, FTC, Mayo Clinic and peer-reviewed sources.
Last updated . Read our editorial standards and how we check reviews. This website is the information site of Thesodaslim, a USA authorized SodaSlim retailer. It is not the manufacturer or the distributor named on the label. We earn money when you buy through our order links.
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