Proponents of L-carnitine and testosterone supplements assert that they have many health benefits that include slowing the aging process. L-carnitine is derived from an amino acid found in most of your body’s cells and is vital in energy production. Testosterone is a hormone involved in maintaining bone density, muscle strength and muscle mass, MayoClinic.com explains. Despite their purported benefits, consult your doctor before using L-carnitine and testosterone in order to avoid any potential adverse effects.

Use and Function

Your body uses L-carnitine and testosterone in different ways. L-carnitine plays a crucial role in converting fat into energy, the University of Maryland Medical Center notes. L-carnitine is produced by your liver and kidneys. Your skeletal muscles, heart and brain store L-carnitine. Males also store L-carnitine in sperm. Testosterone is made in the male testicles and the adrenal system. Women’s ovaries also produce testosterone albeit in smaller amounts relative to men, Drugs.com says. Testosterone is used to alleviate impotence and hormonal imbalances in men. It is also used to treat breast cancer that has metastasized to other parts of the body.

Administration and Dose

Testosterone shots are usually injected subcutaneously, Drugs.com says. Weekly shots are given over the course of two to four weeks but the precise dose varies depending on your specific needs. L-carnitine supplements are available in oral supplement form and the usual dose is about 1 g to 3 g daily, the University of Maryland Medical Center explains. Neither supplement is recommended for children unless prescribed by a doctor.

Side Effects and Interactions

Both L-carnitine and testosterone sometimes cause side effects such as stomach upset, diarrhea and nausea. L-carnitine also causes increased appetite body odor and skin rashes, the University of Maryland Medical Center explains. L-carnitine is used in tandem with chemotherapy drug doxorubicin to potentially protect heart cells from the adverse effects of the chemotherapy medication. Testosterone causes weight gain, anxiety, confusion and memory problems. Testosterone also caused increased penis erections in men as well as changes in menstrual periods in women, Drugs.com explains. Testosterone sometimes causes the sex drive to increase or decrease. Other medications such as blood thinners and insulin interact with insulin.

Benefits

Proponents of L-carnitine and testosterone supplements claim that using these supplements will increase youthful vitality and boost athletic performance. L-carnitine levels in your body decline with age, the Linus Pauling Institute explains. L-carnitine has displayed some potential capacity to alleviate cardiovascular disease, the Office Dietary Supplements explains. There is insufficient evidence, however, to substantiate such claims.