Metabolic & Cardiometabolic
over-the-counter supplements cannot simultaneously build muscle and burn fat
In plain terms: Is there no over-the-counter supplement that both builds muscle and burns fat?
Essentially true — CLA, HMB, carnitine and green-tea extracts do neither meaningfully; the one partial exception is creatine, which nudges lean mass up and fat slightly down, but the fat effect is tiny and a byproduct of training, not real simultaneous fat-burning.
📅 Last reviewed: 2026-07-14 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: All trials, pooled (Meta-analysis)
How the studies fall
The evidence (10)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Whigham 2007 · Am J Clin Nutr | meta-analysis | supports | moderate | Meta-analysis found CLA produces only a trivial fat-mass reduction in humans and no meaningful muscle-building effect. |
| Sung HK et al 2025 · study_type: RCT | RCT | supports | moderate | 12-week RCT of Kaempferia parviflora extract (SIRTMAX) in 83 overweight Korean adults found significant reductions in body fat mass, body fat percentage, and body weight versus control, with no significant change reported in lean body mass |
| Talenezhad 2020 · Clin Nutr ESPEN | meta-analysis | supports | moderate | Meta-analysis of 37 RCTs found L-carnitine produced modest weight loss only, with no muscle-building effect. |
| Chen YC et al 2025 · study_type: observational | observational | contradicts | low | In a Taiwanese adolescent cohort (n=1641), higher glycyrrhizin consumption correlated with lower body fat and higher fat-free mass, especially in nonobese individuals; parallel mouse/preadipocyte experiments showed reduced adiposity and inc |
| Forbes 2019 · J Funct Morphol Kinesiol | meta-analysis | mixed | moderate | Meta-analysis found creatine plus resistance training reduced body-fat percentage by only ~0.55%, a marginal effect alongside lean gains. |
| Lin 2021 · Eur Geriatr Med | meta-analysis | supports | moderate | Meta-analysis found HMB effects on lean mass in older adults are small and controversial, not a reliable muscle-builder plus fat-burner. |
| Desai 2024 · J Strength Cond Res | meta-analysis | mixed | moderate | Meta-analysis found creatine plus training increased lean mass ~1.1 kg and reduced fat ~0.7 kg, but the fat change is small and secondary to training, not true simultaneous fat-burning. |
| Esmaeilnejad 2024 · Br J Nutr | meta-analysis | supports | high | Meta-analysis of 14 RCTs found CLA reduced body weight by under 1 kg with no evidence of simultaneous muscle gain. |
| García-Alonso 2025 · Nutrients | meta-analysis | supports | moderate | Meta-analysis found HMB added to resistance training gave unclear/limited additional body-composition benefit over training alone. |
| Vázquez Cisneros 2017 · Nutr Hosp | meta-analysis | supports | moderate | Systematic review found green tea/EGCG yields modest fat/weight reduction only, with no anabolic muscle effect. |
Disagree, or know a study we missed?
We grade by evidence, not opinions. The way to weigh in is to point us to a study we haven't cited (check the evidence table above first), or to flag a problem with one we have. Every submission is reviewed; if it holds up, the grade updates and shows in Science Changes Its Mind.
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Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.