Lycopene is a carotenoid present in human serum and skin as well as the liver, adrenal glands, lungs, prostate and colon. Lycopene has been found to possess antioxidant and antiproliferative properties in animal and laboratory studies, although activity in humans remains controversial. Numerous studies correlate high intake of lycopene-containing foods or high lycopene serum levels with reduced incidence of cancer, cardiovascular disease, and macular degeneration. However, estimates of lycopene consumption have been based on reported tomato intake, not on the use of lycopene supplements. Since tomatoes are sources of other nutrients, including vitamin C, folate, and potassium, it is not clear that lycopene itself is beneficial. There is no well established definition of "lycopene deficiency," and direct evidence that repletion of low lycopene levels has any benefit is lacking.