VoltraFat burners: do fat-burning pills and drinks work?
Not by much. Reviews of placebo-controlled trials found that the best-known fat burners added between 0.04 kg (green tea) and 1.7 kg (chitosan) to weight loss, and for chitosan, garcinia, CLA and green tea the reviewers judged the effect small or of doubtful clinical importance [2][3][4][5]. Some products sold in Saudi Arabia as natural slimming aids have turned out to contain banned drugs, such as sibutramine [7][8][9].
Your body burns fat when you take in fewer calories than you use. Exercise helps, but 150 to 250 minutes a week of moderate activity on its own brings only modest weight loss [10].
What the trials found
| Fat burner | Extra loss | The evidence |
|---|---|---|
| L-carnitine | 1.33 kg | 9 trials, 911 people. The effect got smaller the longer people took it [1]. |
| Chitosan | 1.7 kg | 15 trials, 1,219 people. The larger, longer and better-run trials found much less, and the reviewers called the effect in high-quality trials minimal [2]. |
| Garcinia (HCA) | 0.88 kg | 9 trials pooled. A small effect of uncertain clinical relevance; stomach and gut side effects were twice as common in one trial [3]. |
| CLA | 0.70 kg | 7 trials of 6 months or more, four of them with serious flaws in how they were reported. Side effects included constipation and diarrhoea [4]. |
| Green tea | 0.04 kg | Trials of 12 to 13 weeks outside Japan; judged not likely to be clinically important [5]. |
Extra loss: the average difference from placebo at the end of the trials.
Fat-burning drinks
The two drinks with trials behind them are green tea and vinegar. Green tea barely moved the scale (above) [5]. In a 12-week trial in Japan, adults drinking 15 ml or 30 ml of apple vinegar a day in a diluted drink lost 1.2 kg and 1.9 kg on average, while the placebo group gained 0.4 kg (calculated); the weight mostly came back within 4 weeks of stopping, and all the trial's authors worked for a vinegar maker [6].
Concentrated green tea pills are a different matter: 800 mg or more of EGCG a day from supplements raised liver enzymes in trials [11]. And whatever the drink, sugar or honey stirred into it adds calories. More on each: green tea, apple cider vinegar and detox juices and teas.
Banned drugs in slimming products
Saudi Arabia's Food and Drug Authority (SFDA) has found banned drugs in products sold as natural slimming aids:
- 2010. A herbal slimming tea, Paiyouji plus, contained sibutramine, a weight-loss drug the SFDA had banned after studies showed a higher risk of heart and artery disease [7].
- 2014. Slimming products sold on social media by unknown sellers contained large amounts of amphetamine derivatives, banned because they harm the heart and are addictive [8].
- 2018. Magrim Super Power Slimming, sold as natural, contained two banned drug substances, sibutramine and phenolphthalein. The SFDA told people not to use it and to get rid of any they had [9].
A "natural" label doesn't tell you what's inside. If you're thinking of taking a slimming product, ask a pharmacist or a doctor first.
What actually burns fat
- Eating fewer calories than you use. That's what makes your body draw on its fat. The calorie calculator gives you a daily target for your goal.
- Exercise, alongside the diet. In the American College of Sports Medicine's position stand, 150 to 250 minutes a week of moderate activity gave only modest weight loss on its own but improved weight loss with a moderate diet, and more than 250 minutes a week was linked to clinically significant weight loss [10].
- Weights, to keep your muscle. In the same review, resistance training didn't add to weight loss, but it may increase fat-free mass and fat loss [10]. See cutting.
- No spot reduction. Six weeks of ab exercises didn't reduce belly fat or waist size [12]. See belly fat.
- Prescription medicines. GLP-1 medicines such as semaglutide are prescribed by a doctor; see Mounjaro, Wegovy and Ozempic.
How Voltra fits in
Voltra gives you a daily calorie and protein target from your details and goal, estimates a meal's calories from a photo, and logs your workouts and cardio, so you can see whether you're staying within your target.
Frequently asked
Do fat burner pills work?
Only a little. In reviews of trials, L-carnitine, chitosan, garcinia, CLA and green tea added between 0.04 and 1.7 kg to weight loss compared with placebo, and most of these effects were judged small or of doubtful clinical importance.
What drink burns belly fat?
No drink burns fat from one place. Green tea added 0.04 kg to weight loss in a Cochrane review, and apple vinegar's small effect in one trial faded once people stopped drinking it.
Does L-carnitine help you lose weight?
A little: across 9 trials with 911 people, those taking carnitine lost 1.33 kg more than those on placebo, and the effect got smaller the longer they took it.
Are slimming pills safe?
Not always. Saudi Arabia's FDA has found banned drugs, including sibutramine, amphetamine derivatives and phenolphthalein, in slimming products sold as natural, some of them through social media.
Sources
- Pooyandjoo M, Nouhi M, Shab-Bidar S, Djafarian K, Olyaeemanesh A (2016). The effect of (L-)carnitine on weight loss in adults: a systematic review and meta-analysis of randomized controlled trials. Obes Rev 17(10):970–976. Abstract. 9 trials, 911 people.
- Jull AB, Ni Mhurchu C, Bennett DA, Dunshea-Mooij CA, Rodgers A (2008). Chitosan for overweight or obesity. Cochrane Database Syst Rev (3):CD003892. Abstract. 15 trials, 1,219 people.
- Onakpoya I, Hung SK, Perry R, Wider B, Ernst E (2011). The use of Garcinia extract (hydroxycitric acid) as a weight loss supplement: a systematic review and meta-analysis of randomised clinical trials. J Obes 2011:509038. Abstract.
- Onakpoya IJ, Posadzki PP, Watson LK, Davies LA, Ernst E (2012). The efficacy of long-term conjugated linoleic acid (CLA) supplementation on body composition in overweight and obese individuals: a systematic review and meta-analysis of randomized clinical trials. Eur J Nutr 51(2):127–134. Abstract.
- Jurgens TM, Whelan AM, Killian L, Doucette S, Kirk S, Foy E (2012). Green tea for weight loss and weight maintenance in overweight or obese adults. Abstract and plain-language summary.
- Kondo T, Kishi M, Fushimi T, Ugajin S, Kaga T (2009). Vinegar intake reduces body weight, body fat mass, and serum triglyceride levels in obese Japanese subjects. Biosci Biotechnol Biochem 73(8):1837–1843. All five authors worked for Mizkan Group Corporation. Body weight from Table 4, p. 1840.
- الهيئة العامة للغذاء والدواء (2010). الهيئة العامة للغذاء والدواء تحذر من شاي أعشاب مغشوش بمواد صيدلانية محظورة لإنقاص الوزن. In Arabic. Warning dated 9 June 2010.
- الهيئة العامة للغذاء والدواء (2014). تحذير حول خطورة بعض منتجات تخفيف الوزن. In Arabic. Warning dated 26 February 2014.
- الهيئة العامة للغذاء والدواء (2018). "الغذاء والدواء" تحذر من مستحضر Magrim Super Power Slimming لغشه بمادتين دوائيتين محظورتين. In Arabic. Warning dated 12 December 2018.
- Donnelly JE, Blair SN, Jakicic JM, Manore MM, Rankin JW, Smith BK; American College of Sports Medicine (2009). American College of Sports Medicine position stand: appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. Med Sci Sports Exerc 41(2):459–471. Abstract.
- EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) (2018). Scientific opinion on the safety of green tea catechins. EFSA Journal 16(4):5239. Read in full on PubMed Central (PMC7009618).
- Vispute SS, Smith JD, LeCheminant JD, Hurley KS (2011). The effect of abdominal exercise on abdominal fat. J Strength Cond Res 25(9):2559–2564. Abstract.
Sources checked on 8 October 2026.
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