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Supplements with no confirmed effect
37 items that sell the most but did not show in studies what they are credited with. This does not mean "harmful" or "do not buy": it is only what the publications show — where there is no effect, where it is weaker than expected, and where data in humans are simply scarce.
How to read this list. Level A means systematic reviews and meta-analyses, B individual good randomised trials, C scarce data. An item can have a high level and still appear here: for example when the effect is statistically real but too small to matter in practice.
| Item | Level | What the studies showed |
|---|---|---|
| Conjugated linoleic acid (CLA) | A | Meta-analysis: about 0.1 kg of fat per week at 3.2 g/day — in practice almost imperceptible |
| Ephedra and ephedrine | A | A moderate weight reduction, but a serious risk to the heart |
| 'Testosterone boosters' (ZMA, tribulus and others) | B | They do not increase testosterone in healthy men |
| Weight gainer | B | It is maltodextrin and sugar at the price of protein; ordinary food gives the same |
| Glutamine | B | Gives almost nothing to healthy athletes: neither growth nor immunity |
| Glucosamine and chondroitin | B | In knee pain the effect is small and borderline significant; it does not restore cartilage |
| Green coffee (chlorogenic acid) | B | Meta-analysis: about 1 kg over 8–12 weeks; the effect is small and inconsistent |
| Ketone esters | B | According to recent data, they worsen endurance rather than improve it |
| Chitosan | B | Meta-analysis: about 1 kg over several months — practically insignificant |
| BCAA (branched-chain amino acids) | B | A weak effect: a complete protein does the same better and cheaper |
| HMB (beta-hydroxy-beta-methylbutyrate) | B | Almost useless for trained individuals: the evidence is contradictory |
| L-carnitine | B | Does not burn fat: the average effect is about 1–1.2 kg and is clinically insignificant |
| Arginine | C | Works poorly orally; the effect is weaker than that of citrulline |
| Astaxanthin | C | The data are few and point in different directions; there is no convincing effect |
| Boron | C | The data on testosterone and strength are weak and contradictory; the effect is not proven |
| Garcinia cambogia | C | The effect on weight is not confirmed; in meta-analyses there is no difference from placebo |
| Glucomannan | C | A soluble fiber with a small effect; the evidence is weak |
| Yohimbine | C | Dangerous: panic attacks, hypertension, prohibited in sport. Data are scarce |
| Raspberry ketone | C | There is no effect in humans; the data are limited to experiments on cells and rodents |
| Coenzyme Q10 (ubiquinone) | C | Raises the blood concentration, improves performance inconsistently |
| Creatine HCl | C | No proven advantages over monohydrate; overpayment |
| Laxogenin | C | A steroidal saponin from Smilax: there are no controlled data in humans |
| Maca | C | In a pilot RCT the result did not differ from placebo; data are scarce |
| Methylsulfonylmethane (MSM) | C | A single RCT showed no protection of muscle after exercise; data are scarce |
| Deer antler velvet | C | The only RCT did not confirm a gain in strength or aerobic capacity |
| Synephrine | C | No benefit has been proven; there is a risk of cardiotoxicity and a rise in blood pressure |
| Theacrine | C | The effect is NOT confirmed: a 2025 study revealed no improvement |
| Turkesterone | C | There are no controlled studies in humans; the popularity is not supported by data |
| Phenibut (β-phenyl-GABA) | C | A prescription drug with a high risk of dependence; it is not a supplement |
| Forskolin (Coleus forskohlii) | C | Small studies of questionable quality; there is no independent confirmation of the effect |
| Sodium phosphate | C | Results are contradictory: one study showed an effect, the second did not |
| Chromium | C | Does not help fat loss or body composition in healthy people; data are scarce |
| Shilajit (mumijo) | C | The only study is open-label, without a comparison group: the effect is not proven |
| Ecdysterone | C | One small RCT showed muscle gain, but the effect is weak and has not been reproduced |
| Green tea extract (EGCG) | C | The effect is small; there is a risk of rare but severe liver injury |
| Apple cider vinegar | C | The claimed effects on weight are not reproduced; the data of the studies raise serious doubts |
| D-ribose | C | The study showed no effect; the benefit for athletes is not confirmed |
Sources
The full list of publications for each item is on its page. Below are the ones this review rests on.
- Efficacy of conjugated linoleic acid for reducing fat mass: a meta-analysis in humans · Whigham LD, Watras AC, Schoeller DA · The American journal of clinical nutrition, 2007 · PMID 17490954
- Current Evidence to Propose Different Food Supplements for Weight Loss: A Comprehensive Review · Watanabe M, Risi R, Masi D · Nutrients, 2020 · PMID 32962190
- Efficacy and safety of ephedra and ephedrine for weight loss and athletic performance: a meta-analysis · Shekelle PG, Hardy ML, Morton SC · JAMA, 2003 · PMID 12672771
- Pharmacology of stimulants prohibited by the World Anti-Doping Agency (WADA) · Docherty JR · British journal of pharmacology, 2008 · PMID 18500382
- Prohibited Contaminants in Dietary Supplements · Mathews NM · Sports health, 2018 · PMID 28850291
- Do "testosterone boosters" really increase serum total testosterone? A systematic review · Morgado A, Tsampoukas G, Sokolakis I · International journal of impotence research, 2024 · PMID 37697053
- Low-fat diets and testosterone in men: Systematic review and meta-analysis of intervention studies · Whittaker J, Wu K · The Journal of steroid biochemistry and molecular biology, 2021 · PMID 33741447
- Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance · Thomas DT, Erdman KA, Burke LM · Journal of the Academy of Nutrition and Dietetics, 2016 · PMID 26920240
- Adulteration of Sports Supplements with Anabolic Steroids-From Innocent Athlete to Vicious Cheater · Puscasiu D, Flangea C, Vlad D · Nutrients, 2025 · PMID 41097223
- Essential Features of Third-Party Certification Programs for Dietary Supplements: A Consensus Statement · Eichner AK, Coyles J, Fedoruk M · Current sports medicine reports, 2019 · PMID 31082891
- International society of sports nutrition position stand: diets and body composition · Aragon AA, Schoenfeld BJ, Wildman R · Journal of the International Society of Sports Nutrition, 2017 · PMID 28630601
- What is the required energy deficit per unit weight loss? · Hall KD · International journal of obesity (2005), 2008 · PMID 17848938
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