What is lycopene, and which foods contain it?

Lycopene is the red pigment that colours tomatoes, watermelon, guava, papaya and the aril of gac fruit (fak khao). It belongs to the carotenoid family, the same family as beta-carotene, but the body does not turn it into vitamin A. In the US Department of Agriculture's FoodData Central, 100 g of raw tomatoes contains 2,573 µg of lycopene and 100 g of raw watermelon 4,532 µg. Lycopene is not a nutrient in the Thai Reference Daily Intakes (Thai RDIs), so there is no Thai daily amount for it.

In short:

• What it is: a red carotenoid pigment, formula C40H56, made only of carbon and hydrogen
• Not vitamin A: the body does not convert it into vitamin A, unlike beta-carotene
• Fresh foods: guava, watermelon, tomatoes, papaya and pink grapefruit; gac aril in Thai and Vietnamese studies
• Cooking and processing: fairly heat-stable in tomato pulp; the amount per 100 g changes with processing
• Daily amount: none in the Thai RDIs; EFSA has an acceptable daily intake for lycopene used as a food additive

This article explains what lycopene is, which foods contain it and how much, and what studies have measured when foods containing it are cooked, dried or stored.

What is lycopene?

PubChem, the US National Library of Medicine's chemical database, describes lycopene as a naturally occurring red carotenoid pigment responsible for the red to pink colours of tomatoes, pink grapefruit and other foods.

What is it made of?

Lycopene has the chemical formula C40H56 and a molecular weight of 536.9. It is a tetraterpene, a molecule built from eight isoprene units, and it contains only carbon and hydrogen atoms. Its long chain is straight rather than closed into rings at the ends. PubChem notes that lycopene can take many shapes: in theory, 1,056 different cis and trans arrangements.

How is lycopene different from beta-carotene?

Both are carotenes, carotenoids made only of carbon and hydrogen. The difference is what the body does with them. The NIH Office of Dietary Supplements (ODS) says beta-carotene, alpha-carotene and beta-cryptoxanthin are provitamin A carotenoids, which the body converts into vitamin A. It says other carotenoids in food, such as lycopene, lutein and zeaxanthin, are not converted into vitamin A and are called non-provitamin A carotenoids. Lycopene therefore does not count towards vitamin A in food tables. For more on how carotenoids differ, see How do astaxanthin, beta-carotene and lutein differ?

Which foods contain lycopene?

Mainly red and pink fruits and vegetables. In the same database, mango and carrots, which are orange, contain almost no lycopene but plenty of beta-carotene.

Lycopene in fresh foods

Source: USDA FoodData Central (SR Legacy), including the entries for raw tomatoes and raw watermelon. Each figure comes from one set of US samples. The guava entry does not state the colour of the flesh.

Watermelon differs by cultivar

A single figure hides large differences between varieties. A 2006 study by the US Department of Agriculture's research service measured 50 commercial red-fleshed watermelon cultivars and found 33 to 100 mg of lycopene per kg of fresh fruit. Sixteen of the 33 seedless cultivars fell into the high or very high groups, and all-trans lycopene made up 84% to 97% of the carotenoids in every cultivar. The study used cultivars grown in the United States, not Thai varieties.

Gac (fak khao)

Gac (Momordica cochinchinensis) is a fruit studied by researchers in Thailand and Vietnam. Its seeds are surrounded by a bright red, oily aril. A 2011 study from Mahasarakham University compared the peel, pulp and aril of Thai gac and found the highest lycopene and beta-carotene in the aril, while the yellow peel had the most lutein. Other studies have measured how much the aril contains:

Sources: Ishida and colleagues (2004) and Wimalasiri and colleagues (2017). The two studies used different samples and methods, so their figures are not directly comparable.

The 2004 USDA study found no lycopene in the fruit's flesh (mesocarp), only in the aril. The 2017 RMIT study found more lycopene in samples collected where temperatures were low (below 14 °C) and at higher elevations. Where the fruit grows changes the amount.

Does cooking or processing change lycopene?

Studies have measured the changes. They describe what happened to the samples, not a way of preparing food.

Tomatoes and tomato products

A 2010 study from KU Leuven in Belgium heated tomato pulp with no other ingredients and described lycopene as rather heat-stable. Heating at 140 °C turned some all-trans lycopene into cis forms, but the cis share of total lycopene stayed small. In food tables, products made by concentrating tomatoes list more lycopene per 100 g than fresh tomatoes:

Source: USDA FoodData Central (SR Legacy).

Drying and storing gac

A 2021 study from King Mongkut's University of Technology North Bangkok and King Mongkut's University of Technology Thonburi spray-dried a water extract of gac aril into a powder. Higher drying temperatures lowered the lycopene in the powder. During storage, the researchers estimated the time until half of the lycopene was lost:

At 55 °C, lycopene fell by up to 91.11% in 18 days. The researchers concluded that the powder's shelf life needs to be improved before it is useful as a food ingredient. These are estimates for one type of powder in one laboratory.

Is there a recommended daily amount of lycopene?

No. Lycopene is not one of the nutrients in the Thai Reference Daily Intakes (Thai RDIs), the daily reference amounts set by Thailand's Ministry of Public Health. Because the body does not convert it into vitamin A, it is not counted towards the Thai RDI for vitamin A (800 µg RAE) either. For the full list of Thai RDIs, see What are the Thai daily reference amounts for each nutrient?

What has EFSA said about lycopene as a food additive?

Lycopene is also used as a food additive, numbered E 160d in the European Union. In a 2017 opinion, the European Food Safety Authority (EFSA) stated that lycopene (E 160d) is an authorised food additive in the EU with an acceptable daily intake (ADI) of 0.5 mg per kg of body weight per day. The ADI is an upper limit used in safety assessment, not a recommended amount.

In the same opinion, EFSA estimated exposure to lycopene as a food additive on the assumption that it is used at the current maximum permitted levels, together with the newly proposed uses. These are scenario figures, not measured intakes. Under this scenario, mean exposure ranged from 0.01 mg per kg of body weight a day in infants to 0.82 mg in toddlers, and high exposure from 0.03 mg to 1.39 mg. EFSA noted that overall intake in this maximum-level scenario would exceed the ADI, but also that its estimates were uncertain and could overstate exposure, and recommended a refined estimate.

Who should talk to a doctor or pharmacist?

Lycopene from everyday foods such as tomatoes, watermelon, guava and papaya is part of a normal diet. Supplements are a different matter.

People who take regular medication

If you take medication regularly and are thinking about a lycopene supplement, tell your doctor or pharmacist what you plan to take.

Pregnant and breastfeeding women

If you are pregnant or breastfeeding, talk to a doctor or pharmacist before using lycopene supplements.

Dietary supplements are not intended to prevent, treat or cure any disease.