22 June 2022
Thought I’d share one of my obsessions on the blog today- green tea! Green tea can be commonly found in skincare products from luxury and drugstore brands such as Estee Lauder, Elizabeth Arden and L’oreal. Lab studies show that green tea has antioxidant, anti-inflammatory and anti-cancer properties. This blogpost is a round up green tea in skincare products and their reported benefits.
Green tea is a popular beverage in Asia. The benefits of drinking green tea are well known- namely anti-cancer, anti-aging, anti-inflammation. To obtain green tea as we know it, harvested leaves of the Camellia sinesis plant are first steamed (to prevent fermentation) and then dried. Prevention of the fermentation process helps to preserve the natural catechins in Camellia sinesis; which gives green tea is benefits. As opposed to black tea which is fermented, green tea has a higher concentration of catechins and polyphenols.
To date, there are more than 900 human, animal and laboratory studies on the health benefits of green tea including its ability to inhibit cancer development and growth. Where the skin is concerned, topical green tea has been shown to protect against cancer, sun damage, inflammation and reverse signs of aging.
Now before you start devouring another cup of green tea ice cream or slather green tea bags on your face, let’s first examine the science of topical green tea.
The use of topical green tea in dermatology is an exciting development ever since green tea was found to reverse the damage from UV rays on the skin. The use of naturally occurring botanical products like green tea and vitamin C is also particularly appealing to well-informed consumers as an alternative way to protect themselves. Compared to synthetic products, botanical products are regarded as safer and less toxic- but that’s a debate for another day.
The antioxidant properties of botanicals are extensively studied and have left to their uses in cancer trials and skincare. Green tea contains antioxidants called polyphenols; more specifically epicatechins, of which the most abundant and well-studied is (-)-epigallocatechin-3-gallate (EGCG) for its anti-inflammatory, sun protective, and anti-cancer properties. Several studies have also confirmed EGCG’s benefits after topical application. The other main active ingredient in green tea extract is caffeine.
The effects of green tea extracts applied to the skin will differ depending on the layer of the skin i.e. epidermis or dermis. In the epidermis, the effect of green tea is mostly antioxidant benefits. In the deeper layer of the epidermis, green tea has a protective effect against UV rays and confers anti-aging benefits by altering the activity of enzymes that break down collagen and hyaluronic acid in the skin. When administered to the dermis, green tea improve microcirculation to improve skin health.
Protection against sun UV ray damage (photoaging)
UV rays from the sun are the biggest cause of aging to the skin and can cause skin cancers.
Polyphenols in green tea (applied or consumed orally) absorb UV rays from the sun and prevent penetration of UV radiation in the skin, thereby enhancing the effect of sunscreen when used together. This helps to reduce skin damage from the sun such as pigmentation, fine lines and wrinkles. Tea connoisseurs will be pleased to know that white also provides photoprotection. However, please note sunscreen should still be a priority. Tea extracts do not filter out sun rays like sunscreen.
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Remember Hugh Jackman’s PSA forsunscreen and sunprotection? The sun-loving actor was a victim of basal cell carcinoma, a type of skin cancer caused by the sun’s harmful UV rays. In fact, due to the aggressive nature of this skin cancer, Jackman has had skin cancer removed at least 6 times.
Besides basal cell carcinoma, the sun’s UV rays play a big role in the cause of another type of skin cancer called squamous cell carcinoma. Our DNA is a major target for UV rays and this leads to DNA damage i.e. mutation and when unchecked, this leads to the development of cancer.
EGCG in green tea has been shown to prevent cancer initiation and growth by multiple pathways including free radical neutralisation and inhibiting cancer spread.
Besides their antioxidant and protective benefits, polyphenols have been found to stimulate collagen formation and slow down the age-related breakdown of collagen, thereby maintaining skin texture and thickness. Polyphenols and caffeine in green tea beverages also improves microcirculation of the skin; increasing oxygen and nutrient delivery for improved skin health.
Inflammation in tissue has been identified as one of the causes that lead to cancer and depletes our body’s antioxidant reserves. Green tea has been found to mitigate inflammation through various pathways and replenish our antioxidant reserves.
Polyphenols in green tea are well known for their antioxidant properties. They neutralise free radicals which damage structures in the skin which give rise to signs of aging and damage skin cell structures like proteins and lipids.
Topically applied green tea has shown to provide better protection against UV rays than when consumed orally. A study in 2001 showed that topical green tea blocked UV ray infiltration and restored the skin’s depleted antioxidant levels after exposure to sunlight.
Oily skin and acne
Green tea emulsion has been found to reduce sebum secretion. Small studies have also shown that topical green tea may improve acne severity. This may be a useful ingredient for patients with oily and sensitive skin. However, if you have acne, my suggestion is to use first line active ingredients like retinoids and anti-bacterial products.
That’s amazing! Does this mean I should start including green tea in my skincare regime? How do I go about it?
So here’s the catch- the benefits of topical green tea is not about tea itself-it is the polyphenols i.e. the active ingredient and percentages matter the most. This means that the concentration of green tea (which is more often quoted than the polyphenol content) is not useful to us. Unfortunately, the variability of green tea preparations across different places also means that the polyphenol content in tea cannot be easily measured.
However, the flip side is that green tea and polyphenols have been found to be very safe to be applied topically. My take on this is: welcome green tea in your skincare routine. While we wait for more robust ways to quantify the constituents of green tea, it is a safe skincare ingredient to start with. Now excuse me while I tuck into my cup of green tea…