During exercise, the body burns more fat by supplementing with L-carnitine
Losing body fat by exercising more is still a very interesting weight loss strategy. This slimming strategy becomes more effective with L-carnitine supplementation. At least if you know how to use those supplements.


English physiologists at the University of Nottingham divided 14 healthy males in their sixties and seventies into 2 groups.For 25 weeks, half of the men consumed a shake with 44 grams of carbohydrates and 14 grams of protein every day. This combination causes a sharp rise in insulin levels.
The men in the other group were given a comparable shake every day, but it also contained 3 grams of carnitine in the form of 4.4 grams of L-carninite L-tartrate. Muscles only absorb carnitine if there is also a relatively large amount of glucose and especially insulin circulating in the bloodstream. But you can read about the importance of insulin and glucose for the absorption of carnitine here and here.
Twice a week the men cycled for an hour at 50 percent of their maximum oxygen uptake. At this intensity you can still have an animated conversation.
Before and after the supplementation period, the British determined how much carnitine was present in the muscle cells of the test subjects. In addition, they got the subjects to cycle for an hour, both before and after supplementation, while determining how many carbohydrates and fatty acids the subjects consumed.
Supplementation with L-carnitine increased the concentration of carnitine in the muscle cells of the subjects by about 20 percent.

This increase in the concentration of carnitine was accompanied by a comparable increase in total fat burning during exercise. The total combustion of fatty acids that were stored in muscle cells plus fatty acids that the muscle cells absorbed from the blood increased by 20 percent.

However, the subjects' fat percentage did not change significantly. Anyway, the researchers hadn't designed their experiment to demonstrate the effect of carnitine on fat loss.
"This is the first study to demonstrate that a carnitine-mediated increase in fat oxidation is achievable in older individuals," the researchers write. It had already been shown that carnitine supplementation can increase fat burning in younger age groups.

"This warrants further investigation given reduced lipid turnover is associated with poor metabolic health in older adults."
Aging Cell. 2021;20:e13303.