Black tea as natural sunscreen
by absorbing UV rays and repairing DNA damage inside the skin.
Topical application of black tea gel significantly reduces skin redness after exposure to UV light, illustrating protective qualities against the radiation across the spectrum, according to researchers.
However protection peaks in the UVB range which accounts for most cases of sunburn.
Protection against the deeply penetrating UVA rays is not so effective.
Natural alternative to sunscreen
The researchers applied an aqueous black tea gel to six subjects, in a three cm 2 patch on the forearm.
The square (and a control patch of similar size but without the black tea gel) was then exposed to UV radiation whilst the rest of the arm was protected.
The study published in the International Journal of Cosmetic Science, reports that no visible erythema (skin reddening) was reported on any of the black tea gel sites throughout the study, whereas after 24 hours all six subjects showed some level of reddening in the control sites.
The authors conclude that black tea gel may protect from a broad range of UV radiation.
Moreover they note that black tea gel can be liberally applied without concern over its toxicological safety.
Black tea absorbs UVB but not A
In addition, the researchers tested the absorption profile of the black tea extract and found that absorption peaked between 250 and 290 nm, suggesting the extract provides protection against rays in the UVB and C spectrum.
However, the absorption levels are less impressive for UVA rays, which are thought to play a role in skin aging and significantly contribute to skin cancer risk.
Increasing importance is being placed on UVA protection in sun care and in August of this year the FDA introduced a new labelling system, demanding for the first time that manufacturers put the UVA protection level provided by the product on the label.
Two fold protection Black tea also exhibits skin repair properties due to its antioxidant components, according to the researchers, who reference a large body of literature that suggests black and green tea help repair UV induced skin damage.
The extract's protective qualities are therefore twofold, conclude the authors: firstly it prevents the skin damage and sunburn by absorbing UV rays and secondly, it repairs UV induced damage to the skin cells.
The authors note that this two fold approach is not provided by conventional sunscreens that only block the UV rays by absorption.
In addition the team highlight that the extract is natural and low cost, with no known toxicological side effects.
Interest in natural alternatives to chemical sunscreens is high as the trend for organic and natural cosmetics gains momentum, and fears over the safety of chemicals in cosmetics become more widespread.
Source: International Journal of Cosmetic Science 2007, volume 29, pages 437-442 "Evaluation of black tea and its protection potential against UV" M. Turoglu and N. Cirgirgil
