Benefits of lycopene
Lycopene, found in many fruits and vegetables -- especially tomatoes and watermelon -- may play an important role in reducing risks of many diseases, including prostate cancer and breast cancer. Some epidemiological studies indicate that high consumption of lycopene may lower the risk of heart disease, atherosclerosis, and macular degeneration.

Antioxidant
Lycopene, one of more than 600 carotenoids found in nature, is a powerful antioxidant, probably more powerful than beta carotene. Studies show it works well together with several other antioxidants, including vitamin E and flavonoids.

Blood Pressure, hypertension
Researchers in Israel have found that a daily dose of lycopene helped lower blood pressure among 31 men and women with mild hypertension. On average, their systolic pressure -- the top number in a blood-pressure reading -- dropped 10 points, while their diastolic pressure, or bottom number, dipped four points.

Erectile dysfunction or impotence
Although it may have such a benefit, I think there are much more potent erection enhancing substances.

Results indicated that lycopene treatment is potentially a new strategy for treating diabetic ED. Pharmazie. 2012. Lycopene ameliorates erectile dysfunction in streptozotocin-induced diabetic rats.

Eyesight and vision
Lycopene is a carotenoid that provides healthy eyesight support. It is found in the eye but lutein and zeaxanthin are found in much higher concentrations.

Heart, blood vessels
Lycopene and other carotenoids may provide healthy support to the cardiovascular system. As an antioxidant it helps protect cholesterol from being oxidized.

Cardiovascular disease is a major contributor to morbidity and mortality in the United States and worldwide. Does providing lycopene through a supplement source is as effective as or more effective than consuming it through whole food sources, specifically the tomato, which is the richest source of lycopene in the Western diet? A review examined clinical trials comparing the efficacy of lycopene supplements with tomato products on intermediate heart and blood vessel risk factors including oxidative stress, inflammation, endothelial function, blood pressure, and lipid metabolism. At present the available clinical research supports consuming tomato-based foods as a first-line approach to cardiovascular health. With the exception of blood pressure management where lycopene supplementation was favored, tomato intake provided more favorable results on cardiovascular risk endpoints than did lycopene supplementation. Whole Food versus Supplement: Comparing the Clinical Evidence of Tomato Intake and Lycopene Supplementation on Cardiovascular Risk Factors. Adv Nutr 2014.

Metabolic syndrome
Advances in Nutrition, January 2019. Lycopene and Metabolic Syndrome: A Systematic Review of the Literature. Cardiometabolic risk factors increase the likelihood of cardiovascular disease development by 2-fold. Lycopene, a potent lipophilic antioxidant, may be able to mediate oxidative stress, a mechanism underpinning metabolic syndrome and its risk factors.

Oral Leukoplakia
One study showed that lycopene supplements were helpful in oral leukoplakia.

Efficacy of oral lycopene in the treatment of oral leukoplakia.
Oral Oncol. 2004.
Fifty-eight clinically and histologically diagnosed patients of oral leukoplakia were randomly divided into three groups. Group A: (8 mg lycopene/day), Group B: (4 mg lycopene /day) and Group C placebo). The duration of the therapy was three months. Clinically the patients in Groups A, B, C had a mean response of 80%, 66% and 12% respectively. Histological evaluation too had similar results. The observed effect of lycopene suggests that it can be effectively and safely used for the management of oral leukoplakia.

Cancer
Population studies show that people who eat large amounts of foods with lycopene, such as cooked tomatoes, have a reduced risk of certain cancers including cervix, mouth, pharynx, esophagus, stomach, pancreas, colon and rectum. While animal and laboratory studies show lycopene to hold promise as a cancer treatment, long term human studies are determine to learn whether the results apply to humans.

Pancreatic cancer
Dietary intake of lycopene is associated with reduced pancreatic cancer risk.
J Nutr. 2005.
A case-control study of 462 histologically confirmed pancreatic cancer cases and 4721 population-based controls in 8 Canadian provinces took place between 1994 and 1997. After adjustment for age, province, BMI, smoking, educational attainment, dietary folate, and total energy intake, lycopene, provided mainly by tomatoes, was associated with a 31% reduction in pancreatic cancer risk among men when comparing the highest and lowest quartiles of intake. Both beta-carotene and total carotenoids were associated with a significantly reduced risk among those who never smoked. The results of this study suggest that a diet rich in tomatoes and tomato-based products with high lycopene content may help reduce pancreatic cancer risk.

Prostate Cancer
Lycopene has shown to potentially play a role in prostate cancer, and perhaps other cancers, including cervix, mouth, pharynx, esophagus, stomach, pancreas, colon and rectum. It helps prevent damage to DNA.

Nat Rev Urol. 2014. Prostate cancer: New data on dietary lycopene suggests reduced risk.

Tomato phytochemicals and prostate cancer risk.
J Nutr. 2004.
Mounting evidence over the past decade suggests that the consumption of fresh and processed tomato products is associated with reduced risk of prostate cancer. The emerging hypothesis is that lycopene, the primary red carotenoid in tomatoes, may be the principle phytochemical responsible for this reduction in risk. A number of potential mechanisms by which it may act have emerged, including serving as an important in vivo antioxidant, enhancing cell-to-cell communication via increasing gap junctions between cells, and modulating cell-cycle progression. Although the effect of lycopene is biologically relevant, the tomato is also an excellent source of nutrients, including folate, vitamin C, and various other carotenoids and phytochemicals, such as polyphenols, which also may be associated with lower cancer risk. Tomatoes also contain significant quantities of potassium, as well as some vitamin A and vitamin E. We carried out cell culture trials to evaluate the effects of tomato carotenoids and tomato polyphenols on growth of prostate cancer cells. We also evaluated the ability of freeze-dried whole-tomato powder or lycopene alone to reduce growth of prostate tumors in rats. This paper reviews the epidemiological evidence, evaluating the relationship between prostate cancer risk and tomato consumption, and presents experimental data from this and other laboratories that support the hypothesis that whole tomato and its phytochemical components such as lycopene reduce the risk of prostate cancer.

Do dietary lycopene and other carotenoids protect against prostate cancer?
Int J Cancer. 2004.
Our results suggest that vegetables and fruits rich in lycopene and other carotenoids may be protective against prostate cancer.

Curtin University of Technology, Perth, investigators conducted a study in southeast China involving 130 patients with prostate cancer, and a comparison group of 274 cancer-free controls. The risk of prostate cancer declined with increasing consumption of lycopene, alpha-carotene, beta-carotene and other carotenoids. Consumption of foods including tomatoes, spinach and citrus fruits was also associated with a reduced cancer risk. The researchers conclude that carotenoids in vegetables and fruits may be inversely related to prostate carcinogenesis among Chinese men. International Journal of Cancer, 2005.

A comparison of lycopene and orchidectomy vs orchidectomy alone in the management of advanced prostate cancer.
BJU Int. 2003.
Adding lycopene to orchidectomy produced a more reliable and consistent decrease in serum PSA level; it not only shrinks the primary tumour but also diminishes the secondary tumors, providing better relief from bone pain and lower urinary tract symptoms, and improving survival compared with orchidectomy alone.

Stomach cancer
J Cancer Prev. 2015. Anticancer Effect of Lycopene in Gastric Carcinogenesis. Gastric cancer ranks as the most common cancer and the second leading cause of cancer-related death in the world. Risk factors of gastric carcinogenesis include oxidative stress, DNA damage, Helicobacter pylori infection, bad eating habits, and smoking. Since oxidative stress is related to DNA damage, smoking, and H. pylori infection, scavenging of reactive oxygen species may be beneficial for prevention of gastric carcinogenesis. Lycopene, one of the naturally occurring carotenoids, has unique structural and chemical features that contributes to a potent antioxidant activity. It shows a potential anticancer activity and reduces gastric cancer incidence.

Mechanism of action
Lycopene acts in many different ways in the body. It works as an antioxidant and it may help reduce DNA damage. Furthermore, lycopene inhibits prostatic IGF-I signaling, IL-6 expression (interleukin), and androgen signaling. Moreover, lycopene improves communication between cells, and induces phase II drug metabolizing enzymes.

Lycopene in food
Foods that are commonly consumed which contain it are tomato products, watermelon, pink grapefruit, apricots, guava, and papaya. Lycopene is one of the major carotenoids in the diet of North Americans and accounts for close to 50% of the carotenoid distribution found in blood. Cooking tomatoes weakens the fruits' cell walls, which makes it easier for your body to absorb. A half-cup of spaghetti sauce has as much lycopene as four or five medium raw tomatoes. There is no Recommended Dietary Allowance or Dietary Reference Intake but studies suggest that about 20 milligrams daily is beneficial. That's roughly 1 cup tomato juice. Besides tomatoes, other pink- and red-hued fruits contain lycopene. These are the amounts for some often-used products:

1 tablespoon tomato ketchup: 2 milligrams
1/4 cup cocktail sauce: 7 milligrams
1/4 cup tomato sauce: 9 milligrams
1/2 cup spaghetti sauce: 20 milligrams
1/2 pound watermelon: 10 milligrams
1 whole pink grapefruit: 3 milligrams
1 papaya: 3 milligrams

You can get lycopene in a supplement, but consuming foods such as canned tomatoes or guava bestows other benefits including vitamins A, C, and E; folate; potassium; and fiber.

Do You need a supplement?
Lycopene, found in many fruits and vegetables -- especially tomatoes and watermelon -- may play an important role in reducing risks of many diseases, including prostate cancer and breast cancer. I think tomatoes and tomato based products are consumed by Americans in a disproportionate basis compared to other fruits and vegetables. In other words, we may be consuming enough in our diet but perhaps not enough of other healthy substances found in a number of fruits and vegetables that are eaten infrequently. Therefore, I am not yet convinced that taking a lycopene supplement will provide benefits to most people, unless their diet is low on tomato based products. Perhaps those who consume adequate or large amounts of tomato based products may be better off taking other types of supplements such as those found in acai, goji, noni, pomegranate, curcumin, soy extracts, artichoke, asparagus, barley grass, etc. The point is, if you plan to take supplements, it may be better to take those that you don't normally consume in your diet as opposed to something like lycopene where it may already be abundant in your diet.

Lycopene Research
Taking lycopene supplements doesn't help athletes who have difficulty breathing during exercise, a condition called exercise-induced bronchospasm (EIB), according to a report in the Annals of Allergy, Asthma, and Immunology.

Dietary lycopene and other carotenoids may protect against prostate cancer, Australian and Chinese researchers report. The findings confirm those of other studies that have identified lycopene as a protective agent against some types of cancers. Lee, of Curtin University of Technology, Perth, and colleagues conducted a study in southeast China involving 130 patients with prostate cancer, and a comparison group of 274 cancer-free "controls."  After factoring in age, total fat and caloric intake, as well as family history, diet appeared to have an influence on the odds of developing prostate cancer. The risk of prostate cancer declined with increasing consumption of lycopene, alpha-carotene, beta-carotene and other carotenoids. Consumption of foods including tomatoes, spinach and citrus fruits was also associated with a reduced cancer risk. The researchers conclude that "carotenoids in vegetables and fruits may be inversely related to prostate carcinogenesis among Chinese men." International Journal of Cancer, 2005.