I’ve been writing about green tea quite a bit here. And one of the questions I keep getting is where to get it and how to use it. Since I at times write about bleeding edge research, no commercial solutions are available and people resort to DIY solutions. In the case of green tea people often just swipe a used teabag over their face.
That’s certainly a cheap and simple option, but is it effective? Can you get the same results I’ve written about just by using brewed green tea? In this post I want to answer this question, to the best of my ability.
Using brewed green tea we run into a few potential problems. First one is dosage, can you get enough epigallocatechin gallate (EGCG) from brewed green tea to reach an effective dose. Second, can you get green tea absorbed through the skin? And finally, what’s the shelf life of this DIY solution, i.e. how often you have to brew the tea?
Before we get started, I want to put a disclaimer out there. This post is far more speculative than my other posts. There are just too many unanswered questions here and I have to make several assumptions. So don’t take this post as the ‘final word’ on the topic. I’m simply taking my best shot here at answering a difficult question.
My main concern is whether you can get enough EGCG into your face from brewed tea.
I made some back of the envelope calculations to see if this is possible. I had to make some assumptions for these calculations, and if my assumptions are off the mark so are the calculations. Here are the assumptions:
- Amount of cream used per application = 1g. This is the amount of cream you use at one time. I got this from the fact that my benzoyl peroxide bottle contains 60g and it lasts about 2 months.
- Concentration of active ingredients in the cream = 2%. Most studies on green tea cream use either 2%, some used 3%. The active ingredient in green tea extract.
- Concentration of EGCG in green tea extract = 60%. Basically how much EGCG there is in green tea extract. In an earlier post I referred to a study that measured 30mg of EGCG from 50mg of green tea extract. This makes sense as EGCG is the major catechin in green tea.
- EGCG per a cup of green tea = 150mg. My first tea hacking post referred a USDA report that showed the average cup of brewed green tea has 180mg of EGCG. I rounded that down to 150mg to be on the safe side.
Based on these assumptions we can do simple math:
- Using 1g of 2% green tea cream means you apply 20mg of green tea extract on your face during a single application.
- And that 20mg of green tea extract has 12mg of EGCG.
Since 2% green tea cream has been shown to both reduce sebum production and effectively treat acne, let’s use this as the target dosage. So now we have to figure out how to get 12mg of EGCG from brewed green tea on your skin.
A cup has 250ml, with 150mg of EGCG per cup it means there is 0.6mg of EGCG per ml of tea. Let’s make this a bit more concrete and talk about teaspoons instead of millilitres. A teaspoon has 5ml, so a single teaspoon of green tea has 3mg of EGCG. To reach the effective dosage of 12mg you need to apply 4 teaspoons of tea on your face.
I don’t know about you, but I’m not sure if you can get 4 teaspoons of liquid tea absorbed through the skin at one sitting. Maybe you can, I really don’t know, but I’m skeptical of it.
Of course you can always brew stronger tea and increase the amount of EGCG per teaspoon, and that means fewer teaspoons to reach the effective dose.
- Normal tea: 4 teaspoons to reach the effective dose.
- 2x strength: 2 teaspoons
- 3x strength: 1.3 teaspoons
- 4x strength: 1 teaspoon
As I mentioned, these calculations are rough at best and rely on some off the cuff assumptions. While they may be wrong, I think they are on the right ballpark. It looks feasible to reach effective dose using brewed green tea.
Aside from dosage, my other major concern is skin penetration and absorption. Is it possible to get green tea absorbed through the skin, and if so what percentage of it gets absorbed and what just sits on the skin and slowly evaporates?
Reading about skin penetration and absorption, I came out with the following points:
- Smaller molecules have easier time passing through the skin. Apparently there’s something called the 500 Dalton rule, which says that molecules heavier than 500 Daltons can’t penetrate the skin. Wikipedia says that the molar mass of EGCG is 458 Daltons, so it’s small enough to pass through the skin.
- Lipid soluble substances penetrate better than water soluble substance, EGCG is water soluble.
- The higher the concentration the more gets through, another reason to brew strong tea.
- I found one test tube study that showed exposure to water improves skin penetration. Not sure whether we would see the same effect in human studies, but it might be a good idea to apply green tea right after shower.
Unfortunately this is a question I cannot definitively answer. I’m sure some EGCG gets absorbed from brewed tea, as bathing/showering can be a major source of chemical exposure.
For more information about skin penetration and absorption, I recommend reading these two articles:
- The Impermeable Facts of Skin Penetration and Absorption
- Penetration of Cosmetic Ingredients
- Skin Care Products – How Much Gets In?
Shelf life is the final concern of this DIY solution. So can you brew the tea in bigger batches or do you have to make a fresh brew every time?
In my previous tea hacking post, I referred to a study about degradation of green tea catechins (antioxidants) under various conditions. The catechins are destroyed as they interact with oxygen and impurities in water. This means that under normal conditions at home about 50% of the catechins are destroyed during the first 5 to 6 hours, basically rendering the DIY solution useless.
I also talked how adding vitamin C to the tea protects the catechins and extends the shelf life. Adding 50mg of vitamin C per cup (250 ml) of tea extends the shelf life enough that you can store the tea for 8 to 9 hours without significant losses in potency.
What this means for you? Plain green tea ‘as it is’ is only good for a single application. Adding some vitamin C allows you to store it overnight and get 2 applications out of it. After that you have to brew another batch.
What about user reviews?
Sometimes we just don’t have enough scientific data to answer a question. In those times we have to resort to the most unreliable form of evidence testimonials and user reviews. So let’s dip to the bottom of the evidence barrel and see what other people have said about topical green tea.
The reviews at acne.org mix both drinking green tea and using it topically, but we can live with that.
Overall the reviews are very positive. At acne.org it gets 4.4 out of 5, while MakeupAlley users rate it as 4.5 out of 5. At both sides over 90% of the users would buy it again or recommend it to a friend. I should also note that some people, minority though, said that topical green tea made their acne worse.
So overall the user reviews are very positive.
I just have to point some problems with these.
- From some glowing reviews it’s obvious that the improvement had little to do with green tea. That’s because using the methods they described is very unlikely to be effective. Some people steeped the bags in cold water – you need hot water to really extract catechins from tea leaves. Other people bottled the tea and used it over several days, but as we’ve discussed brewed tea rapidly loses its potency.
- Many reviews only talk about short-term effects. Like, I started using it 2 weeks ago and it’s a miracle. Acne being somewhat cyclical there are times when your skin is better and times when it’s worse. So was the improvement really because of green tea or just natural fluctuation? And did the effects last? We can’t say.
- Some people also made many changes but attributed the improvement to green tea. Like, since using green tea I’ve also done this, this and that, and my skin is so much better now. What was it that caused the improvement? Again, we can’t say.
My point is that take these reviews with a grain of salt. They do show there’s potential to this DIY green tea treatment.
Green tea honey mask
At acne.org I also noticed reviews for green tea honey mask. This sounds like it could be a good idea. Mixing green tea with honey allows the mixture to stick to your face for longer, which of course helps with skin penetration and absorption.
People said that they mixed some green tea leaves with honey and spread the mixture on their face. Don’t do this. It’s very unlikely that contact with honey extracts any catechins from green tea. You have to steep them in hot water to get the catechins out, and then mix the tea with honey.
Let’s say you’ve decided to give this a go. How would you go about this? Well, this is how I would do it.
- To start with you need good quality tea and brew it correctly. My recommendation is to avoid mass market brands (like Liptons) and get a speciality brand Japanese loose leaf tea. My first tea hacking post shows the big difference in EGCG content of different types of teas.
- Then you need to brew it properly. For best results I would add 4 times the normal amount of tea leaves. This means your tea has 4 times more EGCG. To brew normal tea you would use about 2g of tea leaves per cup of water. As a rough estimate, 2g is about one teaspoon. I might make 100ml (little bit less than 1/2 a cup) at a time, so for that I would use 2 teaspoons of tea leaves.
- Brew the tea for 4 to 5 minutes in boiling water. Boiling water gets the most catechins out of the leaves. And don’t worry, you are not going to destroy the antioxidants, research has shown they can withstand boiling water for 30 minutes or so.
- If you are planning to get more than 1 use out of this, add about 100mg of vitamin C.
- Allow the tea to cool down (don’t add ice as it dilutes the EGCG content) and either mix in with honey for a mask or apply to your face with a cotton pad.
As with all acne treatments, consistency is the key. You need to do this every day over several weeks to really see results. Many of the studies using green tea started showing good results only after 4 weeks. So be patient.
That’s it for this post. I hope you found it helpful. Please let me know what you think in the comments below. Also if you noticed some problems with my assumptions or calculations, please let me know so I can get them sorted out.