Evidence

These uses have been tested in humans or animals.  Safety and effectiveness have not always been proven.  Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Key to grades

A
Strong scientific evidence for this use
B
Good scientific evidence for this use
C
Unclear scientific evidence for this use
D
Fair scientific evidence against this use (it may not work)
F
Strong scientific evidence against this use (it likely does not work)

Grading rationale

Evidence gradeCondition to which grade level applies
C

Antioxidant

Although lycopene is believed to have antioxidant benefits, human research has found mixed results in this area. Most trials looked at lycopene levels in the body or focused on tomatoes or tomato-based products, rather than on lycopene supplements. Although the limited studies on lycopene supplements suggest antioxidant benefits, many products used contained mixed ingredients. More information is needed on the potential effects of lycopene alone.
C

Asthma

A number of studies suggest that lycopene may have antioxidant benefits. These effects are believed to help prevent asthma caused by exercise, although the method is still unclear. Early studies also report that tomato-rich diets may benefit people with asthma. However, available research has used products and supplements with mixed ingredients. More research is needed to better understand the potential effect of lycopene alone.
C

Blood thinner

Although it has not been well studied in humans, early research suggests that lycopene may act as a blood thinner. Most available research in humans has been limited to the use of tomato extract. More research is needed to determine the effects of lycopene-specific therapies.
C

Brain tumors

There is limited research on the use of lycopene together with chemotherapy for brain tumors. Early research suggests that this combination may lack significant benefit over chemotherapy alone. More information is needed on the use of lycopene in cancer patients undergoing chemotherapy.
C

Breast cancer prevention

Lycopene and lycopene-rich foods have been studied as a potential therapy for breast cancer. Early studies on breast cancer recurrence and prevention have looked for a possible link between disease risk and fruit or vegetable intake, tomato consumption, or lycopene levels, with mixed results. There is a lack of studies on lycopene supplementation in breast cancer prevention. More research is needed in this area.
C

Cancer prevention (general)

Some studies suggest that fruit and vegetable-rich diets may be linked to reduced cancer risk. Although it has not been well studied in humans, early research suggests that lycopene may help prevent a number of different cancers, including bladder cancer and skin cancer. However, the reason behind this potential benefit remains unclear. Studies have also looked at the potential role of tomatoes, tomato-based products, and lycopene levels, but not lycopene supplements. At this time, strong evidence in support of lycopene for preventing cancer is lacking. More high-quality research is needed in this area.
C

Cervical cancer prevention

Research has looked at the possible use of lycopene in preventing cervical cancer. Some studies on tomato intake, lycopene levels, and disease risk suggest that lycopene intake may have significant benefit. However, others have found conflicting results. More research is needed before further conclusions can be made.
C

Coronary artery disease

A number of studies suggest that higher lycopene levels may be linked to lower risk of coronary artery disease. These benefits are thought to be due to lycopene's antioxidant effects. It has also been suggested that antioxidants like lycopene may reduce the risk of disease progression. However, results are still mixed, and most studies use mixed ingredient therapies. More information is needed on the potential effects of lycopene alone on this condition.
C

Diabetes (type 2)

Evidence in support of a link between lycopene or lycopene-containing foods and type 2 diabetes risk is currently lacking. In human research, evidence is also lacking to support a benefit of tomato supplementation on a therapeutic effect of long-term tomato supplementation on blood sugar levels in people with type 2 diabetes. More high-quality research is needed in this area.
C

Enlarged prostate

Lycopene has been studied for the prevention of prostate cancer, with mixed results. Early research suggests that lycopene supplementation may slow disease progression associated with enlarged prostate. However, more high-quality studies are needed in this area.
C

Eye disorders

Lycopene has been suggested as a possible treatment for some eye disorders. These include age-related macular degeneration (AMD), which is a breakdown of the retina that may lead to vision loss and cataracts, or clouding of the lens, in the eye. Results from early studies have been mostly negative. Although some studies suggest that there may be a link between higher lycopene levels and reduced risk of cataracts or AMD, there are conflicting results. More evidence is needed before further conclusions can be made.
C

Gum disease

Early evidence reports that a mixed ingredient preparation that contains lycopene and other nutrients found in whole tomatoes may help reduce gum disease, bleeding, and plaque. More research is needed to support these findings, especially on the effects of lycopene alone.
C

Heart disease

Early research in humans has found mixed results on the possible link between tomato products and a reduced risk of heart disease. Strong evidence in support of this benefit is lacking. More high-quality research is needed before firm conclusions can be made.
C

High blood pressure

Lycopene has been studied for its potential protective effects on the heart. However, the results are mixed. While some studies report that lycopene may help lower blood pressure, others suggest a lack of benefit or association between lycopene levels and high blood pressure risk. Most of the therapies studied have contained mixed ingredients. More information is needed on the possible effects of lycopene alone. More high-quality studies are needed in this area.
C

High blood pressure associated with pregnancy

Early research has found inconsistent results on the use of lycopene in preventing high blood pressure in pregnancy. One trial reported a lack of effect, while another reported reduced risk of high blood pressure in pregnancy and fetal growth problems in women having their first child. Most studies looked at mixed-ingredient supplements, and the effects of lycopene alone need to be determined. More high-quality studies are needed.
C

Infertility

It has been suggested that oxidative damage may negatively affect sperm. Lycopene is believed to have antioxidant benefits and has been studied for use in infertility. Although a link between lycopene levels and semen quality has been suggested, studies in humans have found conflicting results. More research is needed in this area.
C

Inflammation

Early research suggests that lycopene from a mixed ingredient supplement or from fresh tomatoes may lack anti-inflammatory benefits. Results have been inconsistent between studies, many of which have looked at mixed-ingredient therapies. More information is needed on the possible effects of lycopene alone.
C

Kidney disease

High-quality studies on the use of lycopene supplementation for kidney disorders or cancer are lacking. Early research suggests that lycopene may lack significant benefit in terms of reducing kidney cell cancer. More research is needed to confirm these results.
C

Lipid lowering effects

Available research suggests that doses of more than 25 milligrams of lycopene daily may lower levels of low-density lipoprotein (LDL, or "bad") cholesterol and total cholesterol. Although this is promising, more high-quality research is needed in this area.
C

Lung cancer prevention

Several studies suggest that increased lycopene intake may reduce the risk of lung cancer. Others report a possible link between consumption of yellow-orange vegetables and lung cancer, as well as lycopene levels and lung cancer. However, there are conflicting results suggesting that lycopene intake or levels may lack benefit in terms of lung cancer development. Due to the lack of consistency among studies, a conclusion is unable to be made at this time.
C

Menopause

Early studies in healthy women suggest that combination lycopene supplementation may reduce some menopausal symptoms. Although this is promising, the effects of lycopene alone are still unknown. More high-quality research is needed in this area.
C

Mouth sores

Studies have found benefits of mixed-ingredient lycopene supplementation on mouth sores. However, evidence is limited, and more information is needed on the potential effects of lycopene alone. More research is needed in this area.
C

Mouth and throat inflammation

Research on lycopene alone and in combination with steroid injections suggests benefits in people with mouth inflammation. More studies on the potential effects of lycopene alone are needed.
C

Ovarian cancer prevention

Some research suggests that the risk of ovarian cancer may decrease with intake of some pigments. However, the potential benefit of lycopene supplementation is unclear. Although lycopene intake has been linked to lower risk of ovarian cancer in premenopausal women, other studies found negative results. More research is needed before conclusions can be made.
C

Pancreatic cancer

Early research reports that dietary lycopene intake from tomatoes may be linked to a lower risk of pancreatic cancer. Although this is promising, more studies are needed in this area.
C

Prostate cancer

Most studies looking at the effects of lycopene on prostate cancer have focused on tomato consumption and have found mixed results. While some research suggests a significant link between lycopene intake from tomatoes with reduced prostate cancer risk, others reported conflicting findings. More information is needed before conclusions can be made on the use of lycopene for this condition.
C

Prostate inflammation

Early research in humans has looked at the use of lycopene together with saw palmetto and selenium in treating prostate inflammation, with benefits seen. Although this is promising, the effects of lycopene alone remain unclear. More high-quality research is needed.
C

Sun protection

The use of lycopene together with other nutrients such as beta-carotene, vitamin C, and vitamin E has been suggested as a possible way to protect skin from sun damage. Lycopene-rich tomato paste has also been suggested as a sun protection method. Although benefits have been seen in small studies, more research is needed before a firm conclusion may be made.
C

Upper gastrointestinal tract & colorectal cancer prevention

There is inconclusive evidence in support of lycopene for use in preventing cancers of the digestive tract. Limited research reports that there may be a significant decrease in cancer risk with high tomato intake. However, other studies have found either a lack of evidence or conflicting results for stomach and colorectal cancer. More information is needed on the possible benefits of lycopene supplementation for these conditions.
D

Immune stimulant

The effect of beta-carotene on immune function has been studied, but research on other similar pigments is limited. A small number of trials on lycopene consumption found a lack of benefit for this purpose. Although information is limited, there is enough evidence available to conclude a lack of effectiveness.
D

Lung function after exercise

Exercise may promote the production of free radicals, which may lead to asthma or related conditions. Lycopene, which is thought to have antioxidant benefits, has been studied for its effects on lung function after exercise. Most research has found conflicting results. Although early evidence suggests that higher lycopene levels may be linked to better lung function, available clinical research shows that mixed-ingredient supplements containing lycopene may lack benefit. More research is needed to confirm these findings.

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Aggressive behavior, AIDS, arsenic poisoning, bone loss, cognitive function, coronary death prevention (death from coronary artery disease), diabetes mellitus type 1, heart attack prevention, human papillomavirus (HPV), lung function, mesothelioma (cancer of the tissue that lines organs), pancreatitis (pancreas inflammation), Parkinson's disease, premature birth prevention, radiation protection, respiratory infections, rheumatoid arthritis, stroke prevention, urinary tract cancer, weight loss.

This evidence-based monograph was prepared by The Natural Standard Research Collaboration

www.naturalstandard.com