How much L-carnitine should a person consume daily?

According to the Office of Dietary Supplements (ODS), a healthy adult or child does not need any daily intake of L-carnitine. The liver and kidneys of a healthy person already produce enough lysine and methionine, the amino acids from which L-carnitine comes from.

The ODS states that the Food and Nutrition Board has not established a recommended dietary allowance for any form of carnitine. The Food and Nutrition Board does not consider it an essential nutrient, except for people who cannot produce enough carnitine on their own, in which case it is a conditionally essential nutrient. Side effects of carnitine supplements include abdominal cramps, diarrhea, nausea and vomiting.