Does L-carnitine help you lose weight?

Yes, a little: across 37 trials, L-carnitine supplements led to about 1.2 kg more weight loss than placebo, mainly in people with overweight.

Published October 2026

Short answer

Yes, but only a little: across 37 trials (2,292 people), L-carnitine led to about 1.2 kg more weight loss than control, mostly in people with overweight or obesity, and the effect shrank over time. Evidence grade B (Moderate). Meta-analyses of 37 and 43 randomised trials agree on a small effect; downgraded once for moderate heterogeneity and an effect that shrinks over time.

Key takeaways

Across 37 trials (2,292 people), L-carnitine lowered body weight by 1.21 kg, BMI by 0.24 and fat mass by 2.08 kg versus control [1].
A 43-trial analysis found the effect only in people with overweight or obesity, not in people on hemodialysis [2].
About 2,000 mg a day gave the largest weight effect, and a 9-trial analysis found weight loss shrank the longer people took it [1][3].
In type 2 diabetes (21 trials, 2,041 people), each 1 g a day lowered HbA1c by 0.16 percentage points and LDL by 0.11 mmol/L, with high variation between trials [4].
In healthy people, L-carnitine raised blood TMAO, a compound linked to artery disease; long-term heart effects are unknown [5].

The short version

Yes, but only a little: across 37 randomized trials (2,292 people), L-carnitine supplements led to 1.21 kg more weight loss than control, along with a small drop in BMI and fat mass [1]. The effect was clearest in people with overweight or obesity, and it shrank the longer people took it [2][3].

What the studies show

Weight and body fat. A 2020 meta-analysis of 37 randomized trials found L-carnitine lowered body weight by 1.21 kg (95% CI 0.68 to 1.73), body mass index by 0.24 and fat mass by 2.08 kg; it did not change waist circumference or body fat percentage [1]. A 2020 update of 43 trials found weight down 1.13 kg and BMI down 0.36, with the effect seen only in overweight and obese adults and not in people on hemodialysis [2]. An earlier 2016 analysis of 9 trials (911 people) found 1.33 kg more weight lost, but the effect fell the longer people took it [3].

How much to take. The dose-response analysis suggested about 2,000 mg a day gave the largest effect on weight [1].

Type 2 diabetes. A 2024 meta-analysis of 21 trials (2,041 people with type 2 diabetes) found every 1 g a day lowered HbA1c, a blood sugar marker, by 0.16 percentage points, LDL cholesterol by 0.11 mmol/L and BMI by 0.37, though results varied widely between trials [4].

The nuances

Small effect. A loss of about 1 kg is modest [1][2].

Lifestyle changes. The 43-trial analysis reported its weight and BMI results for the subgroup where L-carnitine was combined with other lifestyle modifications [2].

A heart-related question mark. A systematic review of 11 trials in healthy people (1 to 4 g a day for 12 to 24 weeks) found L-carnitine raised fasting blood levels of TMAO, a compound thought to promote artery disease, without changing inflammation or oxidative stress markers; the authors said long-term heart effects need study [5].

What this means for you

L-carnitine can lower body weight a little, mainly in people with overweight or obesity, but it is not a weight-loss shortcut [1][2]. Talk to a doctor first if you have diabetes, kidney disease or take medicines such as valproic acid [4][2][6]. For more, see L-Carnitine.

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L-Carnitine — L-carnitine supplements led to about 1.2 kg more weight loss than control in a meta-analysis of 37 randomized trials, mainly in people with overweight or obesi…