Produced naturally by the body, L-carnitine turns fat cells into energy, explains About.com. As of July 2015, not enough scientific evidence exists to support the claims that L-carnitine helps people lose weight.
One study was done with slightly overweight women who took L-carnitine or a placebo for eight weeks. The results showed no difference in total body mass or fat mass between the two groups of patients, About.com reports. Another study done on rats showed the same lack of results, and a second study with L-carnitine done with rats actually resulted in weight gain.
While L-carnitine supplements have not been proven to be effective for weight loss, they do help with heart disease and other heart problems, according to WebMD. Some studies have shown that it helps patients with a history of heart attacks when combined with traditional treatment. It also boosts the health of those who suffer from chest pain, heart failure and peripheral artery disease.
L-carnitine has been recommended to help with thyroid issues, male impotency, memory or thinking problems in older people, and the side effects of chemotherapy. It may also help patients with type 2 diabetes, but more research is still needed, as of 2015. There is no standard dose for L-carnitine supplements, notes WebMD.