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L-Carnitine for Burning Fat

Daniel Brady | November 17, 2012 in Supplements
L-Carnitine Pills

This study looks at the research behind L-Carnitine (Amazon) to see if it works or not. L-Carnitine promises to convert body fat into energy for your body, so that is what we will verify. Read on to see the results.

Study 1: Fat Oxidation Increased 22%

This study showed that slightly overweight subjects supplementing with 3g of L-Carnitine per day for 10 days increased fat oxidation by 22%.[1] This is clearly positive evidence for its efficacy, but shows that you have to take a fair amount of it to see results. 3g per day is 3 or 6 pills, depending on the strength of your pills. For a good product like Now Foods 1000mg L-Carnitine it is 3 pills per day for a cost of almost $1 per day. $1 per day for a 22% increase in fat oxidation seems like a fair price to me, with no unrealistic claims or expectations.

Study 2: No Improvements Reported

This study had overweight women take 4g of L-Carnitine per day for 8 weeks and did 30 minutes of walking 4 days per week. The group who took L-Carnitine and walked didn’t lose more fat or weight than the group who only walked.[2] This study casts doubt on the efficacy of L-Carnitine. Also some L-Carnitine taking participants reported negative side effects including nausea and diarrhea.

Study 3: Reduced Muscle Breakdown from Exercise

Taking 2g L-Carnitine for 3 weeks resulted in a 50%+ reduction in muscle disruption (ruptured cells) after squatting. This improves recovery time and reduces muscle soreness after exercise. [3]

Study 4: No Improvements Reported in Male Bodybuilders

12 male bodybuilders took either 1g of L-Carnitine daily or a placebo for 60 days. No differences were reported between the two groups.[4]


Out of 4 studies, 2 showed benefits and 2 showed no changes, so the efficacy of L-Carnitine is questionable. If you can get it cheaply, it may be worth trying, but it is not a magic bullet.

  1. The effect of l-carnitine on fat oxidation, protein turnover, and body composition in slightly overweight subjects. Klaus D. Wutzke, Henrik Lorenz []
  2. L-Carnitine supplementation combined with aerobic training does not promote weight loss in moderately obese women. Villani, R. G.; Gannon, J.; Self, M.; Rich, P. A. []
  3. L-Carnitine L-tartrate supplementation favorably affects markers of recovery from exercise stress. Volek JS, Kraemer WJ, Rubin MR, Gómez AL, Ratamess NA, Gaynor P. []
  4. The Effect of L-Carnitine Supplementation on Lean Body Mass in Male Amateur Body Builders. R.E. Green, MS, RD, A.M. Levine, PhD, RD, M.J. Gunning, EdD, L.S. Walsh, MS []

Daniel has a strong interest in evidence supported fitness training, preparation and supplementation. His goal is to provide clear information that simply works. He's currently 16 kg of muscle above his starting weight (7kg in the past 12 months), and targeting a continued growth rate of 5kg+ per year.
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