The generic name carnitine refers to different forms, including acetyl-L-carnitine, L-carnitine and propionyl-L-carnitine. While they share some similar jobs, such as ensuring you can convert fat into energy, studies indicate each form may have different strengths. Acetyl-L-carnitine relieves pain from nerve damage and improves age-related sexual dysfunction in men. In any form, carnitine supplements are considered safe, but don’t count on them to improve athletic performance, according to the Linus Pauling Institute.

About Carnitine

Your body produces carnitine from the amino acids lysine and methionine. Then acetyl-L-carnitine is produced from carnitine. Carnitine, including acetyl-L-carnitine, is essential for metabolizing fats into energy. It transports fats and an enzyme vital for fat metabolism into the mitochondria, which are the energy-producing structures inside every cell. Acetyl-L-carnitine may donate the acetyl part of the molecule to help synthesize the neurotransmitter acetylcholine. Carnitine is not an essential part of your diet, but it’s in red meat, poultry, fish and dairy products. If you take supplements, the Linus Pauling institute recommends acetyl-L-carnitine over other forms.

Relieve Pain From Nerve Damage

Acetyl-L-carnitine helps relieve pain due to peripheral neuropathy, which is damage to nerves located outside your brain and spinal cord. Patients with peripheral neuropathy caused by diabetes experienced less pain when they took at least 2 grams of acetyl-L-carnitine daily, according to a review published in the November 2008 issue of the “Annals of Pharmacotherapy.” In another study, women taking acetyl-L-carnitine together with chemotherapy treatments for ovarian cancer had a lower incidence of chemotherapy-induced neuropathy than women who did not receive acetyl-L-carnitine, reports the November 2013 issue of “Oncologist.”

Improve Male Sexual Function

NYU Langone Medical Center reports that acetyl-L-carnitine, taken with propionyl-L-carnitine, helps treat age-related sexual dysfunction in men. In one study, men experiencing sexual dysfunction were treated with testosterone or 2 grams each of acetyl-L-carnitine and propionyl-L-carnitine daily. Both the testosterone and carnitine treatments improved erectile dysfunction, as well as depression and fatigue, according to the study published in the April 2004 issue of “Urology.” A review published in 2007 suggested that L-carnitine and acetyl-L-carnitine may improve sperm motility, but more research is needed to confirm the results, according to PubMed Health.

Slow Down Mitochondrial Aging

Laboratory studies using rats indicate that acetyl-L-carnitine may limit age-related mitochondrial decay in your brain, liver, heart and skeletal muscles, according to the Linus Pauling Institute. Acetyl-L-carnitine given to old rats partially reversed mitochondrial decay in leg muscles, according to the April 2010 issue of “Rejuvenation Research.” The mitochondria are especially vulnerable to reactive molecules called free radicals because these radicals are a natural byproduct of energy production. A study in the February 2009 issue of the “Journal of Cellular and Molecular Medicine” reported that lab rats had less age-related mitochondrial damage and an increase in intact mitochondria in their brains after receiving acetyl-L-carnitine together with an antioxidant.