source of l carnitine Naturals Acetyl L-Carnitine, 500mg, 30 Tablets : Health & Household Acetyl L-Carnitine
Description
Although dosage varies from study to study, in a more general context up to 2,000 mg (2 grams)/day appears safe and effective in the long term

doi: 10.1096/fj.01-0564fje 38 BahnflethCLStruppBJCaudillMACanfieldRL
Pasture-finishing of cattle in Western U.S

Significant differences in RQ were observed at several time points (e.g., 3 min ( p = 0.039), 5 min ( p = 0.017, r = 0.67), 7 min ( p = 0.027)) when L-carnitine was consumed, highlighting that the supplementation led to increased fat oxidation and decreased carbohydrate reliance, especially during the early and middle phases of exercise

Curr Biol