Consumers prefer cosmetic formulas that are promoted for their antioxidant properties, according to Packaged Facts, a market research company. In recent years, retail sales of these products exceeded $4 billion, with skin care products accounting for more than 50% of the total. One of the great antioxidants is green tea, which explains the phenomenal popularity of this material as a beverage and as a component in skin care formulas. Due to growing health consciousness and increasing incidence of chronic diseases, green tea is the highest consumed among all the tea varieties.

According to anthropologists, people have been drinking green tea for 4,000 years—and with good reason; it has several important nutrients such as vitamin C, vitamin B2, folic acid, vitamin E, potassium, calcium, phosphorous and chlorophyll. According to WebMD, drinking green tea improves blood flow, reduces cholesterol, lowers blood pressure, prevents heart-related issues and keeps blood sugar levels stable.

Green tea, also known as camellia sinensis, is a botanical obtained from the leaf and the bud of the plant. The green tea is a botanical extract from fresh leaves of the tea plant obtained by steaming and drying them at elevated temperature, being careful to avoid oxidation and polymerization of the polyphenolic compounds. Whether orally consumed or topically applied, green tea has been shown to display significant antioxidant, chemo-preventative, immune-modulatory, and anti-inflammatory activity, affecting the biochemical pathways in cell proliferation.^1,2

A Look at the Data
Green tea is well established as a potent source of antioxidant called polyphenols, the same beneficial compounds found in fruits and vegetables. The leaf also is source of a superstar antioxidant called epigallocatechin-gallate (EGCG) as well as additional notable substances including fluoride, catechins and tannins. Green tea also contains three types of flavonoids: kaempferol, quercetin and myricetin. The material’s anti-aging effects are achieved by decreasing inflammation and scavenging free radicals. Polyphenols modulate biochemical pathways that are important in cell proliferation and inflammatory responses.³

Some Drawbacks
Green tea is included in skin care products due to polyphenols’ antioxidant effects. However, green tea is thought to be challenging to formulate because of the inherent hydrophilic nature of EGCG, which limits absorption into the human skin.^4,5 However, green tea is thought to have outstanding potential in traditional sunscreens as a photoprotection enhancer.^6,7 The photoprotective activity of orally administered or topically applied green tea has been supported in various clinical studies.^{8, 9,10} It is very important to know the amount of green tea catechins in a formulation to judge its efficacy. Whether it is used as an extract of camellia seed oil or leaf powder, the effectiveness of green tea in cosmetics is dependent on factors such as concentration level, processing method and quality of tea. Seven years ago, Sommer and Zhu reported that green tea-filled cotton pads applied once daily for 20 minutes prior to treatment with light-emitting diodes, reduced wrinkles in one month versus 10 months of light treatment alone.¹¹

In another study, a topical cosmetic formulation with 6% green tea extract was applied on the skin for 30 days. Skin moisture was enhanced and skin roughness was significantly diminished.¹² A 60-day placebo controlled comparative split-face study in 33 healthy Asian men was conducted to evaluate the efficacy of cosmetic formulation containing green tea and lotus extract for facial wrinkles. Study results showed improvement in skin roughness, smoothness and wrinkling.¹³ Topically-applied green tea appears to reduce skin inflammation and neutralize free radicals, which explains its popularity in anti-aging skin care products. Its effects are difficult to quantify because it does not have the capacity to increase collagen synthesis or decrease the depth of existing wrinkles. It functions as an antioxidant, suggesting that topically applied green tea could help protect skin from UV radiation.¹⁴

Clearly, there is a reason for optimism that topically applied green tea will gain momentum as an increasingly selected therapeutic option. There is certainly precedent. According to Dr. Leslie Baumann MD, green tea polyphenols are among the most frequently studied herbal agents used in medicine.

References

1. Arch. Dermatol. 2000 Aug, 136(8) 989-94.
2. Oxid. Med. Cell longev. 2012:560682
3. Katiyar SK et al Arch. Dermatol. 136:989,2000
4. Dermatol. Ther, 2007, Sep-Oct 20(5) : 322-9
5. J. Clin Aesth.  Dermatol. 2010 Feb:3(2) :22-41.
6. hotodermat. Photoimmunolo Photomed.2007,  Feb.23(1)48-56
7. Skin Res Technol 2009 Aug: 15 (3) 338-45
8. Exp Dermatol 2009 Jan :18(1) :69-77
9. Exp Dermatol. 2009 June : 18 (6) :522-6
10. Arch. Biochem Biophys 2011 Apr 15 : 508 (2)  152-8
11. Photomed. Laser Surg 2009, Dec 27(6)-969-71.
12. Dermatol. Ther. 2013 May-June 26(3) : 267-71
13. Rejuvenation Res 2013 Apr. 16(2) 91-7
14. Complement Ther Clin Pract 2014, Feb 20(1): 11-5.

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Navin M. Geria
Chief Scientific Officer
Ayurderm Technologies LLC
[email protected]

Navin Geria, former Pfizer Research Fellow is a cosmetic and pharmaceutical product development chemist and the chief scientific officer of AyurDerm Technologies LLC, which provides Ayurvedic, natural and cosmeceutical custom formulation development and consulting services to the spa-wellness-dermatology industries. He has launched dozens of cosmeceutical and ayurvedic anti-aging products. Geria has more than 30 years of experience in the personal care industry and was previously with Clairol, Warner-Lambert, Schick-Energizer, Bristol-Myers and Spa Dermaceuticals. He has nearly 20 US patents and has been published extensively. Geria edited the “Handbook of Skin-Aging Theories for Cosmetic Formulation Development” focus book published in April 2016 by Harry’s Cosmeticology. He is a speaker, moderator and chairman at cosmetic industry events.