Lycopene

Lycopene is the red pigment of ripe tomatoes. It belongs to the carotenoid family, the same family as beta-carotene and lutein. Carotenoids give fruits and flowers yellow, orange and red colors that attract animals to spread pollen and seeds. In green tissue they help photosynthesis and shield it from too much light.

Unusually for plants, a ripe tomato piles up large amounts of lycopene as its chloroplasts change into color-holding chromoplasts.

Lycopene is not a source of vitamin A. Unlike beta-carotene, it has no provitamin A activity. Even so, lycopene and beta-carotene are the two most abundant carotenoids in human blood and tissues. Lycopene has also been found in the prostate.

Cooking helps here. In one trial, the same 23 mg of lycopene gave 3.8 times more absorption from tomato paste than from fresh tomatoes. And the shape of the molecule matters. Tangerine tomatoes, a variety rich in the bent cis form of lycopene, gave about 8.5 times more absorption than red tomato juice.

Health benefits of lycopene

• ★★Mixed results for blood pressureA pooled analysis of 6 trials found lycopene supplements lowered the top number about 5 points (4.95 mm Hg systolic), more above 12 mg daily. A 34-trial review found no clear change, and another found only a tomato extract worked, not synthetic lycopene.
• ★★Mixed results for LDL cholesterolAt 25 mg or more a day, lycopene lowered LDL (“bad”) cholesterol about 10% (10.35 mg/dL) across 12 trials; lower doses had no clear effect. A 34-trial review found no clear effect on LDL, HDL or triglycerides.
• ★★More UV needed to redden skinIn a pooled analysis of 21 trials in healthy people, tomato foods and lycopene pills raised the UV dose needed to redden skin. In one small trial, 40 g of tomato paste daily cut UV reddening by 40% after 10 weeks.
• ★★No clear effect on PSA, a prostate markerIn 6 trials, lycopene or tomato extract did not clearly change PSA, a prostate screening blood marker (difference 0.12 ng/mL, possibly chance). In men whose prostate cancer had not spread, another analysis found PSA fell by 3.74 µg/L only in those starting at 6.5 µg/L or more.
• ★Prostate cancer protection not provenThe FDA found no credible evidence that lycopene lowers prostate cancer risk. A pooled analysis of 42 studies linked higher lycopene to 12% lower prostate cancer risk, but such studies cannot prove cause.

Foods high in lycopene

Tomatoes are the richest source of lycopene in the Western diet. In the USDA data below, guava (5,204 µg per 100 g) and watermelon (4,532 µg) come first. Then come raw tomatoes (2,573 µg), papaya (1,828 µg) and grapefruit (1,135 µg), while mango and carrots hold only a few micrograms.

The ranking covers foods USDA measured, mostly raw produce, so it does not show how much concentrated tomato products hold. The two tomato sauces made for one trial held 26 and 33 mg per 100 g. That is about 10 and 13 times the USDA figure for raw tomatoes.

Cooking and processing raise how much of it you absorb, mainly when oil is present. In a single-dose trial, 23 mg of lycopene was eaten with 15 g of corn oil. Tomato paste gave 2.5 times the peak blood level and 3.8 times the total absorption of fresh tomatoes.

In an earlier trial, blood lycopene rose only after people drank tomato juice boiled for an hour with 1% corn oil. Unprocessed juice did not raise it.

In 11 people, 470 g of diced tomatoes cooked with 25 mL of olive oil raised blood trans-lycopene by 82%. Tomatoes cooked without added oil did not clearly change it. Extra heating alone only tended to help in another trial, where crushing the tomatoes mattered more.

How lycopene works

Most of what we know about how lycopene works comes from test tubes and artificial membranes. Researchers keep coming back to three ideas. It calms a reactive form of oxygen, and it lies flat in the fatty core of cell membranes. And heating bends it into a shape the gut takes up better.

Here is each one, and what has been seen in people.

It calms singlet oxygen

Singlet oxygen is an excited, reactive form of oxygen. Carotenoids can quench it, which means they calm it before it reacts with something else. In a 1989 test-tube study, lycopene had the highest quenching rate of the compounds compared. It reached 31 billion per molar per second, against 14 for beta-carotene and 0.3 for vitamin E.

That is more than 100 times vitamin E, and a later review calls lycopene almost twice as fast as beta-carotene. But speed is not the whole story. Vitamin E is far more plentiful in blood (22 micromolar against 0.7 for lycopene). At those levels, the authors found the quenching capacities of the two were comparable.

It lies flat in the fatty core of membranes

Lycopene has no oxygen-containing end groups, so it cannot anchor at the watery edge of a membrane the way astaxanthin can. A computer simulation of a skin-lipid bilayer placed lycopene flat (parallel to the surface) in the fatty middle, while zeaxanthin stood upright.

In lab tests on membranes rich in polyunsaturated fats, that position came with a cost. Lycopene and beta-carotene disordered the bilayer and raised fat-damage products by more than 85%, while astaxanthin lowered them by 40%.

Not every test agrees. In another lab study using liposomes (tiny fat bubbles), lycopene ranked first of several carotenoids and vitamin E at blocking a fat-damage marker. Lycopene plus lutein worked better together than either alone. The result depends on the membrane and the test, so no single experiment settles whether lycopene protects or harms membranes in the body.

Heat bends it into a shape the gut takes up better

In fresh tomatoes lycopene is essentially the straight all-trans shape. In human blood and tissues, more than half is bent cis forms. Heat and light turn all-trans into cis, and the share of cis rises with temperature and cooking time.

In ferrets fed lycopene that was 91% all-trans, the lymph that carries absorbed fat held 77.4% cis. The authors link this to cis forms dissolving better in the gut’s bile micelles.

Two human trials agree. In 12 adults, a sauce heat-processed to 45% cis beat a sauce with 5% cis. It gave more lycopene in the blood fat fraction per milligram eaten (7.30 against 4.74). In 11 people, juice from tangerine tomatoes, 94% cis, gave 48% absorption against 5% from red tomato juice, which was 10% cis.

The cis shift is not the only reason cooked tomatoes work. In another trial, fresh tomatoes and paste had the same isomer pattern, yet paste gave 3.8 times the absorption. Crushing tomatoes more finely raised absorption in a third trial. Breaking up the plant cells seems to matter too.

What has been seen in people

These effects are much easier to show in a dish than in a person. Across 34 trials, lycopene lowered MDA, a blood marker of fat damage, but not CRP, IL-6 or most other markers. Skin trials with tomato paste mostly show a higher UV dose to redden skin, but one trial found none.

In prostate cancer, pooled trials found no change in PSA. Where benefits appear, such as the roughly 5 mmHg drop in systolic pressure in some meta-analyses, they are modest and not consistent across studies. All of these are among the study cards above.

Is lycopene safe? Supplements, dose and interactions

Lycopene from food has not been flagged as a safety problem in the sources we read. For lycopene used as a food color (E 160d), EFSA, the European food safety agency, set an acceptable daily intake (ADI). It is 0.5 mg per kg of body weight a day, about 35 mg for a 70 kg adult. The figure came from a one-year rat study in which the liver enzyme ALT rose at higher doses.

The joint FAO/WHO expert committee (JECFA) instead set its ADI to “not specified” in 2009, and EFSA kept its own figure in 2010. In 2023 EFSA added that, for high consumers, lycopene from natural sources plus food-color use could pass the ADI. It also could not establish the safety of a tomato extract added to cereal bars, drinks and supplements.

• Trial doses and side effects. Most trials used 10 to 30 mg a day. Two trials gave 16 mg of lycopene in 40 to 55 g of tomato paste. And 30 mg is about the amount in 1.2 kg of raw tomatoes by USDA data. In 81 men taking 30 mg for 4 months, no adverse effects were attributed to lycopene. A trial of 15 mg capsules or lycopene-rich foods for 6 months found them acceptable and well tolerated.
• Orange skin. Very large amounts of tomato foods can turn the skin yellow-orange (lycopenemia). Case reports describe it as benign and harmless.
• Blood pressure drugs. Several meta-analyses found a small drop in systolic pressure. Whether it adds to blood pressure medicine is theoretical, because we found no controlled interaction study. People on such drugs can mention supplements to their doctor.
• Children and pregnancy. EFSA’s estimates of lycopene intake from food colors are highest in toddlers. At the maximum permitted levels, the mean was 0.82 mg/kg a day, above the ADI. The trials above did not test safety in pregnancy or breastfeeding, so ask your doctor before taking supplements.

How to get more lycopene

• Heat and crush tomatoes. Tomato paste gave 3.8 times the absorption of fresh tomatoes, and guava and watermelon top the USDA ranking per 100 g.
• Add some fat. Cooking diced tomatoes with 25 mL of olive oil raised blood trans-lycopene by 82%. A review puts the fat needed for carotenoid absorption at roughly 3 to 5 g per meal.
• Food or supplement. A review of trials comparing the two found tomato foods gave more favorable results than lycopene supplements, except for blood pressure, where supplements were favored.

History of lycopene

Lycopene takes its name from Lycopersicon, the name of a former tomato genus. Methods to isolate it were first reported in 1910, and its structure was settled by 1931. It is also approved as a food color, E 160d in the European Union.

The health story began with a test tube. In 1989 researchers reported that lycopene was the fastest carotenoid they tested at quenching singlet oxygen. In 1992 and 1997, researchers showed that blood lycopene rose after people ate heat-processed tomato products, but not unprocessed ones. They also showed that paste was absorbed far better than fresh tomatoes. In 2002 the Health Professionals Follow-Up Study linked tomato sauce to lower prostate cancer risk.

That interest reached regulators. In 2004 the FDA received two petitions for qualified health claims on tomatoes, lycopene and cancer. Its 2007 review found no credible evidence for lycopene itself and only very limited evidence for tomatoes. Regulators also disagreed on safety. In 2009 JECFA replaced its lycopene ADI with “not specified”, while EFSA kept 0.5 mg per kg of body weight a day.

Frequently asked questions about lycopene

What does lycopene do for the body?

The best-supported effects in trials are small. Some meta-analyses found systolic blood pressure lower by about 5 mmHg. Small trials found a higher UV dose needed to redden skin after weeks of tomato paste. A 34-trial meta-analysis found no effect on blood pressure or blood fats, though, and no finding here reaches strong evidence. Lycopene is not converted to vitamin A.

Which foods are high in lycopene?

Guava, watermelon and tomatoes lead the USDA ranking, at 5,204, 4,532 and 2,573 µg per 100 g, followed by papaya and grapefruit. Tomato products such as paste and sauce are far more concentrated. The two sauces made for one trial held 26 and 33 mg per 100 g.

Are cooked tomatoes better than raw for lycopene?

Yes, for absorption. In one trial, tomato paste gave 3.8 times the absorption of fresh tomatoes from the same 23 mg of lycopene. In another, tomatoes cooked with olive oil raised blood trans-lycopene by 82%. Eat them with a meal that has some fat. We found no trial of the best time of day.

Does lycopene lower the risk of prostate cancer?

Not proven. A meta-analysis of 42 studies found 12% lower risk with higher lycopene intake or blood levels. But a nested case-control study of 1,683 cases found no link, and a 15-study pooled analysis found none except for aggressive disease. Trials show no effect on PSA, and the FDA found no credible evidence for lycopene itself.

How much lycopene should you take a day?

No dose is proven best. Most trials used 10 to 30 mg a day, and the blood pressure meta-analysis found more effect above 12 mg. EFSA’s ADI for lycopene as a food color is 0.5 mg per kg of body weight a day, about 35 mg for a 70 kg adult. A can of tomato juice in one trial held 30 mg.

Does lycopene have side effects?

Trials reported few. In 81 men, 30 mg a day for 4 months caused no adverse effects attributed to lycopene. Very large amounts of tomato foods can turn skin yellow-orange, which case reports call benign. Pregnancy and breastfeeding were not tested in the trials we found.

Does lycopene protect skin from the sun?

A little, in small trials, and not enough to replace sunscreen. Tomato paste with about 16 mg of lycopene cut UV reddening by 40% after 10 weeks in one trial. It raised the UV dose that caused reddening in another. A 10-week trial of capsules or paste found no change, and the trials did not test it against sunscreen.

Lycopene vs beta-carotene: what is the difference?

Beta-carotene is a provitamin A carotenoid, while lycopene has no provitamin A activity. In test tubes, lycopene quenched singlet oxygen at 31 billion per molar per second against 14 for beta-carotene. Both are nonpolar and sit in the fatty core of membranes, and both raised fat damage in one model-membrane test.