Green Tea: Is It An Effective Hair Loss Treatment?

Article Summary

Green tea extract contains epigallocatechin gallate (EGCG) and many other compounds that allegedly improve hair growth. On the one hand, in vitro studies suggest that EGCG might inhibit hair follicle damage. On the other hand, human studies do not yet exist showing that green tea – as a supplement or topical – can improve hair loss. Case studies suggest that green tea extract, in combination with other ingredients, might improve hair growth. But the effects may vary greatly depending on whether green tea is applied topically or ingested orally, which changes the metabolism of green tea and thereby its effects in hair follicle sites. This article explores the science behind green tea & hair loss, along with its safety and efficacy as a hair growth aid.

Full Article

Green tea, derived from the Camellia sinensis plant, is known for its antioxidant properties and numerous health benefits. Rich in catechins and polyphenols, green tea is often said to aid in weight loss, boost metabolism, and promote overall well-being. But what about supporting hair growth?

In relation to hair loss, the components present in green tea – including epigallocatechin gallate (EGCG), epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), and catechin gallate (CG) – are known antioxidants which may help to combat oxidative stress, a major contributor to hair follicle damage and subsequent hair loss. Furthermore, it is thought that green tea has some 5-ɑ-reductase inhibiting properties. However, this has only been demonstrated in vitro.

In this article, we’ll dive into the mechanistic evidence supporting (or not supporting) the components of green tea for hair loss, examine the clinical evidence (or lack thereof), and determine whether green tea might be best delivered topically or orally for hair growth.

Key Takeaways

• What is it? A plant known for its antioxidant and anti-inflammatory properties and numerous health benefits, including weight loss, metabolism, and overall well-being. Some components of green tea have been found to have some beneficial effects on hair growth, including caffeine and EGCG. The in vitro data shows that polyphenols present in green tea, like EGCG and some of its metabolites, might have some 5ɑ-reductase inhibiting properties. EGCG can upregulate miRNAs associated with hair growth and downregulate miRNAs related to cell death. Furthermore, in vivo studies in mice show some positive effects on hair growth; however, the study only showed the results in one mouse.
• Clinical Data.
  • We could only find one study that used EGCG alone; however, it was conducted on only three people with no hair loss problems. The participants applied 10% EGCG topically to their scalps. After treatment, the hair follicles were dissected, and it was found that the proteins involved in hair follicle cell growth increased, and those involved in cell death decreased.^[1]Kwon, O.S., Han, J.H., Yoo, H.G., Chung, J.H., Cho, K.H., Eun, H.C., Kim, K.H. (2007). Human hair growth enhancement in vitro by green tea epigallocatechin-3-gallate (EGCG). Phytomedicine. 14. … Continue reading 
  • The second clinical study was conducted on two men with androgenic alopecia. The participants were simultaneously administered topical and oral formulations that contained several ingredients (including EGCG). While the results appeared remarkable, we cannot be sure if EGCG contributed to the hair growth as it was just one of a number of ingredients.
• Safety. Green tea is considered safe when administered topically and orally. However, if extreme amounts are orally ingested, it may cause acute liver damage.
• Evidence Quality. Green tea scored 6/100 for evidence quality by our metrics.
• Best Practices. Both topical and oral green tea extracts have their advantages and disadvantages, so it may be worth experimenting with both to determine the best use of the product. However, based on the current evidence available, we do not recommend using green tea as a standalone treatment for hair loss.

What is Green Tea?

Green tea, made from the leaves of the Camellia sinensis plant, is a popular beverage known for its abundance of polyphenols and catechins. These compounds contribute to the diverse range of biological and pharmacological effects of green tea, including as an antioxidant, anti-inflammatory, and antimicrobial. Additionally, green tea has been associated with potential benefits such as weight management, improved cardiovascular health, and even reduced risk of certain cancers.^[2]Luo, Q., Luo, L., Zhao, J., Wang, Y., Luo, H. (2023). Biological and potential mechanisms of Tea’s bioactive compounds: An Updated Review. Journal of Advanced Research. 2090-1232. Available at: … Continue reading 

Green Tea Components and Their Impact on Hair Follicle Biology

Green tea contains several components, some of which might positively affect hair follicle biology.

Caffeine

Green tea’s caffeine has been found to stimulate hair follicles and extend the growth (anagen) phase of the hair cycle, leading to increased hair growth and reduced shedding. An ex vivo study was conducted using isolated hair follicles from the vertex areas of male AGA patients. The hair follicles were cultivated for 120 – 192 hours with a growth medium containing different testosterone concentrations with or without caffeine. The growth of the hair follicles was measured daily. While testosterone was found to suppress hair follicle growth, this was counteracted by 0.001% and 0.005% caffeine.^[3]Fischer, T.W., Hipler, U.C., and Elsner, P. (2007). Effect of caffeine and testosterone on the proliferation of human hair follicles in vitro. The International Society of Dermatology. 46. 27-35. … Continue reading Furthermore, in hair follicles treated with caffeine, absolute hair shaft length was significantly improved under both concentrations of caffeine compared with the control after 72 hours of cultivation.

Further studies using microdissected hair follicles have found that caffeine can prolong the growing (anagen) stage of the hair follicle cycle, increase hair matrix keratinocyte growth, and upregulate growth factor expression, like insulin-like growth factor 1 (IGF-1).^[5]Fischer, T.W., Herczeg-Lisztes, E., Funk, W., Zilikens, D., Biro, T., and Paus, R. (2014). Differential effects of caffeine on hair shaft elongation, matrix and outer root sheath keratinocyte … Continue reading Additionally, caffeine has been found to alleviate hair follicle damage from UV radiation.^[6]Gherardinin, J., Wegner, J., Cheret, J., Ghatak, S., Lehmann, J., Alam, M., Jiminez, F., Funk, W., Bohm, M., Botchkareva, N.V., Ward, C., Paus, R., and Bertolini, M. (2019). Transepidermal UV … Continue reading  You can find out more about the effects of caffeine on hair regrowth here.

Polyphenols and Catechins

Green tea polyphenols can have antioxidant, anti-inflammatory, and vasodilatory effects that may improve scalp microcirculation and nutrient delivery to hair follicles.^[7]Di Sotto, A., Gulli, M., Percaccio, E., Vitalone, A., Mazzanti, G., Di Giacomo, S. (2022). Efficacy and Safety of Oral Green Tea Preparations in Skin Ailments: A Systematic Review of Clinical … Continue reading 

Studies in mice have also shown that oral supplementation with green tea polyphenol extracts can significantly improve hair growth compared to controls. One study included 60 female Balb/black mice with spontaneous hair loss at six months.^[8]Esfandiari, A., and Kelley, P. (2005). The Effects of Tea Polyphenolic Compounds on Hair Loss among Rodents. Journal of the National Medical Association. 96(6). 816-818 The mice were split evenly into two groups: Group A, which received polyphenol extracts of green tea in the drinking water, and Group B, which received drinking water only for six months. Hair regrowth was analyzed by measuring the difference in bare skin in a marked area before and after treatment. The study found that 33% of mice receiving green tea extract in their drinking water developed hair regrowth within six months with an average surface regrowth rate of 1.6 mm2 per month, which was a significant increase compared to the placebo group (Figure 1). 

However, this study only shows one photo of one mouse, so we do not know if any improvements were due to a few “hyper-responders” to the treatment instead of an overall average improvement of all mice.

Epicatechin gallate epigallocatechin gallate (EGCG) has been shown to inhibit the activity of 5ɑ-reductase, the enzyme responsible for converting testosterone into dihydrotestosterone (DHT). In a cell-free enzyme assay, epicatechin gallate (ECG) and EGCG were both able to effectively inhibit 5ɑ-reductase compared to epicatechin and epigallocatechin.^[10]Liao, S., Hiipakka, R.A. (1995). Selective inhibition of steroid 5 alpha-reductase isozymes by tea epicatechin-3-gallate and epigallocatechin-3-gallate.  Biochem and Biophysical Research … Continue reading^[11]Hiipakka, R.A., Zhang, H.Z., Dai, W., Dai, Q., Liao, S. (2002). Structure-activity relationships for inhibition of human 5α-reductases by polyphenols. Biochemical Pharmacology. 63. 1165-1176. … Continue reading Whole cell assays, however, found that neither EGCG nor its metabolites had any effect on 5ɑ-reductase, suggesting that it cannot cross the cell barrier, which presents a significant hurdle for hair loss treatments.

You can read our article about whether EGCG benefits hair follicle growth here. Here’s a quick summary of what we found through:

• EGCG up-regulates several miRNAs involved in cell growth and survival and cell cycle regulation, which promote cell growth and suppress growth arrest.
• EGCG down-regulates miRNAs that suppress the continuation of the cell cycle and subsequent cell growth and induce cell death.
• Decreases intracellular reactive oxygen species (ROS) levels and senescence
• Overall, EGCG promotes cell and hair follicle growth through the upregulation of cell growth pathways and downregulation of apoptosis pathways.

So, we have examined how the components of green tea might affect hair regrowth, but what about clinical outcomes? 

Is Green Tea Clinically Effective at Treating Hair Loss?

We have found only two studies using green tea polyphenols in humans. The first one was an uncontrolled (so no placebo or comparator) case series in which a topical and oral formulation containing ℽ-linoleic acid, ꞵ-sitosterol, EGCG, and genistein was administered at the same time to two male participants with AGA over 270 days.^[13]Geno, M., Bauman, A. (2020). An Uncontrolled Case Series Using a Botanically Derived, ꞵ-Cyclodextrin Inclusion Complex in Two Androgenetic Alopecia-Affected Male Subjects. Cosmetics. 7(65). 1-12. … Continue reading Hairs were counted in a specific scalp area at baseline and every 90 days after that.

Study Results

The results look remarkable based on the images. By Day 270, neither of the participants showed any sign of hair loss (Figures 4 & 5). 

 

Furthermore, the researchers mention that by day 270, most hairs observed in both subjects were full thickness/terminal.

Problems

While these results are very positive, there are a few clear problems with the study:

Sample number: The sample size is extremely small, with only two participants, so it is not representative of the population, and we cannot know if it would work in the same way as everyone.

Potential conflict of interest: One of the study authors (Geno Marcovici) is affiliated with the company that manufactures the test formulation.

Inclusion of EGCG: While EGCG was included, it was among three other ingredients, each with potential benefits on hair growth. Therefore, we can’t conclude whether EGCG had any real effect on hair follicle growth.  So, while we know that positive effects were observed, we can’t determine whether it was due to EGCG.

The dosing of Beta–Cyclodextrins: One of the unique elements of this topical & supplement combination is its formulation: the active ingredients are delivered with beta-cyclodextrins, which may offer better penetration capacity for the ingredients to hair follicle sites. Having said that, beta cyclodextrins have an upper tolerable limit of 5 mg per kg daily for humans.^[16]https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/beta-cyclodextrin# Upon further scrutiny of these product formulations, we’re unsure how its manufacturers are making the supplement & topical without also exceeding the upper tolerable daily limit established for safety purposes in adult men and women.

Any Other Studies?

The only other study found on green tea polyphenols was on three volunteers without hair loss problems. A topical containing 10% EGCG in ethanol or ethanol vehicles was applied once daily to two areas of the scalp for four days. After this time, hair follicles were excised from the scalp and dissected to isolate the dermal papillae. Protein levels of key markers involved in cell growth (Akt and Erk) were then measured alongside markers involved in the induction or suppression of apoptosis.^[17]Kwon, O.S., Han, J.H., Yoo, H.G., Chung, J.H., Cho, K.H., Eun, H.C., Kim, K.H. (2007). Human hair growth enhancement in vitro by green tea epigallocatechin-3-gallate (EGCG). Phytomedicine. 14. … Continue reading

Erk and Akt were both found to be increased, suggesting that EGCG can improve cell growth. Additionally, Bcl-2 (a suppressor of cell death) was also found to be increased, with a concomitant reduction of Bax (an inducer of cell death) (Figure 6).  

However, the big problem with this study is that none of the participants had any form of hair loss! So, we can’t assume that any positive effects gained from the EGCG would actually help with any hair loss conditions.

Which Administration is More Effective: Topical or Oral?

Green tea extracts can be administered topically or orally. However, they are susceptible to degradation when exposed to light, heat, and oxygen, reducing their effectiveness. This low chemical stability can affect the potency of green tea products, whether administered orally or topically.^[19]Nain, C.W., Mignoelt, E., Herent, M.F., Question-Leclerq, J., Debier, C., Paige, M.M., Larondelle, Y. (2022). The Catechins Profile of Green Tea Extracts Affects the Antioxidant Activity and … Continue reading

Topical Application

Topical application of green tea involves directly administering green tea extracts or formulations onto the scalp. This method allows for the localized delivery of polyphenolic compounds, particularly EGCG. As previously mentioned, EGCG has been shown to possess several properties that may benefit hair health. By targeting the scalp directly, topical green tea may exert its effects more rapidly and efficiently on hair follicles, potentially inhibiting the activity of DHT.

Does Topical Application Make Sense Biologically?

While the clinical evidence is lacking, there is a potential for topical application of green tea. Applying green tea topically allows for direct delivery of its bioactive compounds to the scalp, where they can exert their effects on hair follicles. Furthermore, as it contains ingredients that can affect 5ɑ-reductase, topical application might minimize systemic absorption and potential unwanted side effects.

However, EGCG is a non-polar compound that is not soluble in water. Because of this non-polarity, it typically stays in the stratum corneum (the outer layer of skin) rather than the epidermis or dermis.^[20]Zillich, O.V., Schweiggert-Weisz, U., Hasenkopf, K., Eiser, P., Kerscher, M. Release and in vitro skin permeation of polyphenols from cosmetic emulsions. International Journal of Cosmetic Science. … Continue reading

So, topical application may encounter problems of absorption through the skin.

Oral Consumption

Consuming green tea orally (ingesting green tea or supplements) allows the bioactive compounds to be absorbed and distributed systemically (throughout the body). These compounds then undergo metabolism in the liver. During Phase I metabolism, various enzymes catalyze oxidation, reduction, and hydrolysis reactions, leading to the formulation of metabolites with altered chemical structures compared to the parent compounds. For example, EGCG can undergo methylation, sulfation, or glucuronidation, resulting in metabolites like epicatechin, epigallocatechin, and epicatechin gallate.^[21]Feng, W.Y. (2006). Metabolism of green tea catechins: an overview. Current Drug Metabolism. 7(7). 755-809. Available at: https://doi.org/10.2174/138920006778520552

EGCG is primarily absorbed in the small intestine and metabolized in the large intestine; however, it has high bioavailability and is readily present in plasma after intake. After Phase I metabolism, the derivatives do not have the same high bioavailability as EGCG and, therefore, likely have different effects.^[22]Manach, C., Williamson, G., Morand, C., Scalbert, A., and Remsey, C. (2005). Bioavailability and bio-efficiency of polyphenols in humans. I. Review of 97 bioavailability studies. The American Journal … Continue reading

To further show this, as can be seen above, only epicatechin gallate has similar effects on 5ɑ-reductase as EGCG, whereas other metabolites have no effect.^[23]Hiipakka, R.A., Zhang, H.Z., Dai, W., Dai, Q., Liao, S. (2002). Structure-activity relationships for inhibition of human 5α-reductases by polyphenols. Biochemical Pharmacology. 63. 1165-1176. … Continue reading

How Safe is Green Tea?

Green tea is considered safe for up to 8 cups daily for oral ingestion.^[24]National Center for Complementary and Integrative Health. (2020). Green Tea. NIH. Available at: https://www.nccih.nih.gov/health/green-tea (Accessed: 25 April 2024) However, ingestion of large amounts of green tea (such as in mixed preparations taken in powder or tablet form) has been implicated in cases of acute liver injury, which is worth keeping in mind for people with liver issues.^[25]Grajecko, D., Ogica, A., Boenisch, O., Hubener, P., Kluge, S. (2022). Green tea extract-associated acute liver injury: case report and review. Clinical Liver Disease. 20(6). 181-187. Available at: … Continue reading For topical administration, one systematic review covered the efficacy and safety of green tea when used in cosmetics. It confirmed that green tea has no allergenic or irritating effects after administration.^[26]Koch, W., Zagorska, J., Marzec, Z., Kukula-Koch, W. (2019). Applications of Tea (Camellia sinensis) and Its Active Constituents in Cosmetics. Molecules. 24(23). 4277. Available at: … Continue reading

Is Green Tea For Me?

You may want to experiment with green tea if:

• You are happy using a product with no real clinical data (and sparse in vitro data) supporting its efficacy
• You want to experiment with the efficacy of oral or topical administration 
• You’re already using more effective hair growth treatments, and are considering green tea as an adjuvant treatment

Otherwise, we cannot recommend using this ingredient due to the lack of clinical evidence.