Acetyl-L-carnitine is a mainly neuroactive version of L-carnitine. ALCAR has been investigated in several clinical studies in depression, mild dementia, fatigue and fatigue.
Fat burning and weight reduction – L-Carnitin more effective with strongly calorie-reduced parliamentary allowance
L-Carnitine has gained popularity through its strong presence as a dietary supplement in sports studios and is considered a classic fat burner. Although several clinical studies have shown that taking L-carnitine measurably increases fat burning, this could not be shown so clearly for weight loss. One problem in the existing studies is that there is no comparability between the works and many contradictory results are available. Unfortunately the participants were not on a calorie-reduced diet, but could eat as they pleased.
In contrast, there is an older German study in which the participants were placed on a diet and were given L-carnitine or a placebo. In a placebo-controlled study with overweight participants, these were placed on a 5-day fasting phase without food and a subsequent 2-day, strongly calorie-reduced diet phase. In the 7 days the participants consumed only very few calories. Those who received 4g of L-carnitine daily for fasting felt less hungry, less tired and felt fitter overall physically than those who were put on a strict diet.
The intake led to a higher weight loss and a stronger reduction of the hip circumference. Possibly the drastic diet increased the L-Carnitin need, so that the income of L-Carnitin could adjust these again. As a result, taking L-carnitine capsules or powders for fasting, such as intermittent fasting, or for diets that are generally very low in calories would be a good idea. Older people seem to respond better to carnitine and lost -3 kg more than the control group in a double-blind study.
It is unclear whether the L-carnitine administered was able to directly stimulate fat burning or whether it was more effective against age-related fatigue and was able to stimulate physical activity and thus calorie burning. In another double-blind placebo-controlled study, women with polycystic ovarian syndrome lost -2.7 kg and -2 cm abdominal, and -2.5 cm hip circumference more if they took only 250 mg L-carnitine for 12 weeks. The intake can be significantly increased by the accompanying intake of carbohydrates. However, the amount of carbohydrates must not impair the desired calorie reduction; after all, L-carnitine cannot cause or support weight loss without a diet.
L-Carnitine as support for athletes
In some studies, they increased neither aerobic nor anaerobic performance. Other studies showed an increase in anaerobic sprint performance when glycine propionyl L-carnitine was taken before the performance test, but the required dose is unclear. The combination of caffeine and L-carnitine was able to stimulate the endurance performance and release of fatty acids from the fat cells better than the individual active ingredients alone.
L-carnitine and acetyl L-carnitine in older people
Older people seem to benefit more from L-carnitine and acetyl L-carnitine than younger people, as the concentration of both substances in muscle tissue decreases with age. Research with animal models shows that the administration of acetyl L-carnitine stimulated the formation of mitochondria in older animals and stimulated the degradation of attached age pigments in nerve cells and the eye lens. A meta-analysis of clinical trials shows that older people experienced an improvement in cognitive abilities after 2-3 months of use at a dose range of 1.5-3 g daily due to acetyl L-carnitine in dementia symptoms. Other clinical studies showed an improvement in physical weakness and mental fatigue when seniors took L-carnitine.
According to the available publications, the intake of L-carnitine results in an increase in muscle mass, a reduction in body fat, more urge for activity and improved memory performance in older people. Nevertheless, the number and quality of the studies are still not sufficient to adequately prove this effect or to seriously advertise L-carnitine for these purposes.
Acetyl-L-carnitine stimulates the release of the neurotransmitters serotonin and alertness and is used by some users as a substitute for caffeine. However, the stimulating property is significantly lower than that of caffeine and differs in the way it is stimulated. In animal models, ALCAR also stimulated the release of nerve growth factors such as NGF, GDNF, BDNF.