Sunburn

Antioxidants may protect the skin from sunburn due to free radical–producing ultraviolet rays.¹ Combinations of 1,000 to 2,000 IU per day of vitamin E and 2,000 to 3,000 mg per day of vitamin C, but neither given alone, have a significant protective effect against ultraviolet rays, according to double-blind studies.^2,3,4

Oral synthetic beta-carotene alone was not found to provide effective protection when given in amounts of 15 mg per day or for only a few weeks’ time in larger amounts of 60 to 90 mg per day, but it has been effective either in very large (180 mg per day) amounts or in smaller amounts (30 mg per day) in combination with topical sunscreen.^5,6,7,8,9

Natural sources of beta-carotene or other carotenoids have been more consistently shown to protect against sunburn. One controlled study found that taking a supplement of natural carotenoids (almost all of which was beta-carotene) in daily amounts of 30 mg, 60 mg, and 90 mg gave progressively more protection against ultraviolet rays.¹⁰ In another controlled study, either 24 mg per day of natural beta-carotene or 24 mg per day of a carotenoid combination of equal amounts beta-carotene, lutein, and lycopene helped protect skin from ultraviolet rays.¹¹ A preliminary study compared synthetic lycopene (10.1 mg per day), a natural tomato extract containing 9.8 mg of lycopene per day plus additional amounts of other carotenoids, and a solubilized tomato drink (designed to increase lycopene absorption) containing 8.2 mg of lycopene plus additional amounts of other carotenoids. After 12 weeks, only the two tomato-based products were shown to give significant protection against burning by ultraviolet light.¹²

Still other trials have tested combinations of several antioxidants. One preliminary study found that a daily combination of beta-carotene (6 mg), lycopene (6 mg), vitamin E (15 IU), and selenium for seven weeks protected against ultraviolet light.¹³ However, a double-blind trial of a combination of smaller amounts of several carotenoids, vitamins C and E, selenium, and proanthocyanidins did not find significant UV protection compared with placebo.¹⁴ Similarly, in a controlled trial, a combination of selenium, copper, and vitamins was found to be ineffective.¹⁵

It should be noted that while oral protection from sunburn has been demonstrated with several types of antioxidants, the degree of protection (typically less than an SPF of 2) is much less than that provided by currently available topical sunscreens. On the other hand, these modest effects will provide some added protection to skin areas where sunscreen is also used and will give a small amount of protection to sun-exposed areas where sunscreen is not applied. However, oral protection from sunburn is not instantaneous; maximum effects are not reached until these antioxidants have been used for about eight to ten weeks.^16,17

Caution: Synthetic beta-carotene has been linked to increased risk of lung cancer in smokers. Until more is known, smokers should avoid all beta-carotene supplements.

Antioxidants may protect the skin from sunburn due to free radical–producing ultraviolet rays.¹⁸ Combinations of 1,000 to 2,000 IU per day of vitamin E and 2,000 to 3,000 mg per day of vitamin C, but neither given alone, have a significant protective effect against ultraviolet rays, according to double-blind studies.^19,20,21

Oral synthetic beta-carotene alone was not found to provide effective protection when given in amounts of 15 mg per day or for only a few weeks’ time in larger amounts of 60 to 90 mg per day, but it has been effective either in very large amounts (180 mg per day) or in smaller amounts (30 mg per day) in combination with topical sunscreen.^{22,23,24,25,26}

Natural sources of beta-carotene or other carotenoids have been more consistently shown to protect against sunburn. One controlled study found that taking a supplement of natural carotenoids (almost all of which was beta-carotene) in daily amounts of 30 mg, 60 mg, and 90 mg gave progressively more protection against ultraviolet rays.²⁷ In another controlled study, either 24 mg per day of natural beta-carotene or 24 mg per day of a carotenoid combination of equal amounts beta-carotene, lutein, and lycopene helped protect skin from ultraviolet rays.²⁸ A preliminary study compared synthetic lycopene (10.1 mg per day), a natural tomato extract containing 9.8 mg of lycopene per day plus additional amounts of other carotenoids, and a solubilized tomato drink (designed to increase lycopene absorption) containing 8.2 mg of lycopene plus additional amounts of other carotenoids. After 12 weeks, only the two tomato-based products were shown to give significant protection against burning by ultraviolet light.²⁹

Still other trials have tested combinations of several antioxidants. One preliminary study found that a daily combination of beta-carotene (6 mg), lycopene (6 mg), vitamin E (15 IU), and selenium for seven weeks protected against ultraviolet light.³⁰ However, a double-blind trial of a combination of smaller amounts of several carotenoids, vitamins C and E, selenium, and proanthocyanidins did not find significant UV protection compared with placebo.³¹ Similarly, in a controlled trial, a combination of selenium, copper, and vitamins was found to be ineffective.³²

It should be noted that while protection from sunburn has been demonstrated with several types of orally administered antioxidants, the degree of protection (typically less than an SPF of 2) is much less than that provided by currently available topical sunscreens. On the other hand, these modest effects will provide some added protection to skin areas where sunscreen is also used and will give a small amount of protection to sun-exposed areas where sunscreen is not applied. However, oral protection from sunburn is not instantaneous; maximum effects are not reached until these antioxidants have been used for about eight to ten weeks.^33,34

Extracts of Polypodium leucotomos (PL), a fern native to Central and South America, have antioxidant and anti-inflammatory activity.³⁵ Several preliminary human studies have reported that a 50:1 PL extract in amounts of either 7.5 mg per 2.2 pounds of body weight or 1,080 mg given orally on the evening before and on the day of testing reduces the burning effect of ultraviolet rays.^36,37,38 Placebo-controlled research is needed to verify these protective effects.

Green tea(Camellia sinensis) contains polyphenols that have antioxidant and anti-inflammatory activity, and animal and preliminary human studies have suggested that these polyphenols, when given orally or used topically, can protect skin against ultraviolet rays.^39,40,41,42 In a small, controlled human study, topical application of green tea extracts containing from 2.5 to 10% polyphenols significantly reduced the amount of burning from exposure to ultraviolet rays, with the 10% solution exerting greater protective effect.⁴³

Antioxidants may protect the skin from sunburn due to free radical–producing ultraviolet rays.⁴⁴ Combinations of 1,000 to 2,000 IU per day of vitamin E and 2,000 to 3,000 mg per day of vitamin C, but neither given alone, have a significant protective effect against ultraviolet rays, according to double-blind studies.^45,46,47

Oral synthetic beta-carotene alone was not found to provide effective protection when given in amounts of 15 mg per day or for only a few weeks’ time in larger amounts of 60 to 90 mg per day, but it has been effective either in very large (180 mg per day) amounts or in smaller amounts (30 mg per day) in combination with topical sunscreen.^{48,49,50,51,52}

Natural sources of beta-carotene or other carotenoids have been more consistently shown to protect against sunburn. One controlled study found that taking a supplement of natural carotenoids (almost all of which was beta-carotene) in daily amounts of 30 mg, 60 mg, and 90 mg gave progressively more protection against ultraviolet rays.⁵³ In another controlled study, either 24 mg per day of natural beta-carotene or 24 mg per day of a carotenoid combination of equal amounts beta-carotene, lutein, and lycopene helped protect skin from ultraviolet rays.⁵⁴ A preliminary study compared synthetic lycopene (10.1 mg per day), a natural tomato extract containing 9.8 mg of lycopene per day plus additional amounts of other carotenoids, and a solubilized tomato drink (designed to increase lycopene absorption) containing 8.2 mg of lycopene plus additional amounts of other carotenoids. After 12 weeks, only the two tomato-based products were shown to give significant protection against burning by ultraviolet light.⁵⁵

It should be noted that while oral protection from sunburn has been demonstrated with several types of antioxidants, the degree of protection (typically less than an SPF of 2) is much less than that provided by currently available topical sunscreens. On the other hand, these modest effects will provide some added protection to skin areas where sunscreen is also used and will give a small amount of protection to sun-exposed areas where sunscreen is not applied. However, oral protection from sunburn is not instantaneous; maximum effects are not reached until these antioxidants have been used for about eight to ten weeks.^56,57

Antioxidants have been studied as topical agents for protection against sunburn. Animal studies have found sunscreen-like effects from topical application of a vitamin C and vitamin E combination, and a controlled human study reported ultraviolet protection from the use of a lotion containing 0.02% to 0.05% of the selenium-containing amino acid known as selenomethionine.^58,59 The topical use of the hormone melatonin has been shown to protect human skin against ultraviolet rays in double-blind research.^60,61 A double-blind human trial tested topical vitamins C and E and melatonin, alone and in combinations, and found the highest degrees of protection from combination formulations containing 2% vitamin E, 5% vitamin C, and 1% to 2.5% melatonin.⁶² Other studies in which topical antioxidants were applied after ultraviolet exposure have found no benefits.^63,64

Proanthocyanidins (OPCs) are a group of flavonoids found in pine bark, grape seed, and other plant sources. In a preliminary trial, volunteers were supplemented with Pycnogenol, an extract of French maritime pine bark rich in OPCs, in the amount of 1.1 mg per 2.2 pounds of body weight per day for the first four weeks, and 1.66 mg per 2.2 pounds of body weight per day for the next four weeks.⁶⁵ Compared with ultraviolet sensitivity before supplementation, the lower amount of Pycnogenol was found to significantly increase the amount of ultraviolet rays necessary to cause sunburn, and the higher amount was significantly more effective than the lower amount.

Trials have tested combinations of several antioxidants. One preliminary study found that a daily combination of beta-carotene (6 mg), lycopene (6 mg), vitamin E (15 IU), and selenium for seven weeks protected against ultraviolet light.⁶⁶ However, a double-blind trial of a combination of smaller amounts of several carotenoids, vitamins C and E, selenium, and proanthocyanidins did not find significant UV protection compared with placebo.⁶⁷ Similarly, in a controlled trial, a combination of selenium, copper, and vitamins was found to be ineffective.⁶⁸

Proanthocyanidins (OPCs) are a group of flavonoids found in pine bark, grape seed, and other plant sources. In a preliminary trial, volunteers were supplemented with Pycnogenol, an extract of French maritime pine bark rich in OPCs, in the amount of 1.1 mg per 2.2 pounds of body weight per day for the first four weeks, and 1.66 mg per 2.2 pounds of body weight per day for the next four weeks.⁶⁹ Compared with ultraviolet sensitivity before supplementation, the lower amount of Pycnogenol was found to significantly increase the amount of ultraviolet rays necessary to cause sunburn, and the higher amount was significantly more effective than the lower amount.

Antioxidants have been studied as topical agents for protection against sunburn. Animal studies have found sunscreen-like effects from topical application of a vitamin C and vitamin E combination, and a controlled human study reported ultraviolet protection from the use of a lotion containing 0.02% to 0.05% of the selenium-containing amino acid known as selenomethionine.^70,71 The topical use of the hormone melatonin has been shown to protect human skin against ultraviolet rays in double-blind research.^72,73 A double-blind human trial tested topical vitamins C and E and melatonin, alone and in combinations, and found the highest degrees of protection from combination formulations containing 2% vitamin E, 5% vitamin C, and 1% to 2.5% melatonin.⁷⁴ Other studies in which topical antioxidants were applied after ultraviolet exposure have found no benefits.^75,76

Topical aloe (Aloe vera) is often recommended for soothing burns, but only one preliminary human study involving sunburn has been published, and applying aloe gel after ultraviolet exposure had no effect on reddening of the skin.⁷⁷ No research has investigated whether applying aloe gel before ultraviolet exposure might be more effective.