Science Shows Coffee May Reduce Acne

By Seppo | Diet


Research shows that drinking coffee regularly reduces insulin and blood sugar levels while caffeine does the opposite. The likely implication is that coffee can protect against acne whereas other caffeinated drinks could be bad for your skin.

In this post I’m going to explain what the science says about the effect of coffee and caffeine on acne, and what this means to you.

Brief on insulin-acne connection

Let’s start with a brief recap on how insulin and high blood sugar level contributes to acne. When blood sugar level increases the pancreas responds by releasing the hormone insulin. Insulin in turn stimulates the release of other acne-causing hormones, such as insulin like growth factor 1 (IGF-1) and androgens. These hormones increase sebum production and skin cell growth, leading to blocked pores and acne. For more detailed explanation, please see the hormonal acne post.

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The implication is that anything that has a persistent negative effect on insulin level (i.e. causes insulin resistance/increases insulin level) can be bad for your skin. This is the reason sugar and milk cause acne.

Coffee has well-documented effects on both blood sugar and insulin levels, and these are the most likely mechanisms by which it affects acne. So let’s see what the science says about the effect on coffee on blood sugar health.

The effect of regular coffee consumption on blood sugar health

One of the most impressive studies I found was a Dutch study on older people. The study included 1312 over 50 years old Dutch people. The researchers administered an oral glucose tolerance test (OGTT) at the start of the study and another one 6 to 7 years later.  OGTT measures how well your body handles sugar and involves drinking a cup of water with 75 grams of sugar (for reference 20 oz/590 ml bottle of Coke has 65g of sugar) and having blood sugar and insulin levels measured 2 hours later. Caffeine consumption was tracked with a food frequency questionnaire.

The study showed that regular coffee consumption was very good for blood sugar health. This image shows the incidence of impaired glucose tolerance (IGT) vs. coffee consumption.

Coffee and risk for impaired glucose tolerance

The blue bars indicate the percentage of people who developed impaired glucose tolerance (IGT) during the study. IGT is diagnosed when your blood sugar level remains abnormally high at the 2 hour mark of the OGTT. It means your body had trouble clearing sugar from bloodstream and indicates insulin resistance.

The red line shows risk ratio between groups, with the 2 or fewer cups per day being the reference point. Those who drank 7 or more cups per day had risk ratio of 0.44, so they were 56% less likely to develop IGT than those who drank 2 or fewer cups per day. Makes sense?

The paper also contained an interesting table that showed the change in blood sugar health parameters when daily coffee consumption goes up by 5 cups. Note that negative values mean improvement, as negative values refers to lower, and thus better, values.

2-hour glucose -8.8%
Fasting glucose -0.8%
2-hour insulin -19.7%
Fasting insulin -5.6%
Insulin resistance (HOMA-IR) -6.3%

Source: Coffee consumption and incidence of impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes: the Hoorn Study.

The ‘2-hour’ values refer to measurements in OGTT and thus represent what happens after a meal. Those are fairly significant improvements, especially the nearly 20% lower insulin level.

This is by no means an isolated result, 19 out of 22 such studies show similar results. So there’s overwhelming evidence to show that drinking coffee regularly lowers blood sugar and insulin levels, and thus is indirectly good for acne.

Caffeinated beverages may have the opposite effect

Though drinking coffee is good for blood sugar and insulin levels, caffeine alone may have the opposite effect. There has long been a paradox in coffee research. Epidemiological studies (like the Dutch study above) show protective effect from coffee, but short-term studies where participants are given caffeine almost uniformly show caffeine causes insulin resistance and higher blood sugar level.

The implication is that caffeine in coffee impairs glucose tolerance but over time something else in coffee offsets this negative effect. It could be the antioxidants in coffee or something else, scientist haven’t figured it out yet.

From this you could conclude that decaffeinated coffee is the best choice. It, presumably, still has the beneficial substances in coffee but has minimal amounts of caffeine. A 2006 study showed this indeed is the case.

In this study 11 participants got regular coffee (RCOF), decaffeinated coffee (DECAF), a caffeine pill (CAF), or a placebo pill (PL) on 4 separate occasions. 60 minutes later OGTT was administered. Here are the results:

Effect of coffee and caffeine on blood sugar

Source: The Glucose Intolerance Induced by Caffeinated Coffee Ingestion Is Less Pronounced than That Due to Alkaloid Caffeine in Men.

Note that in those graphs the time ‘0 min’ refers to when caffeine/coffee/etc. was ingested, and time ’60 min’ when the sugar drink was given.

As you can see, ingestion of decaffeinated coffee resulted in the lowest blood sugar and insulin levels and ingestion of pure caffeine resulted in the highest levels, with regular coffee being in the middle. And we are not talking about small differences here. The researchers calculated ‘area under curve’ figures (a good estimate of total amount of insulin or glucose in the blood during 2 hours) for all the cases. Compared to RCOF, DECAF resulted in about 50% less glucose in the blood during the 2 hours, and a whopping 69% reduction when compared to CAF. In the case of insulin, DECAF resulted in 23% lower insulin load than RCOF and 38% lower when compared to CAF.

This was a very small study (only 11 participants), but I’m using it as an example for two reasons: bigger studies on caffeine have shown similar results, and it’s one of the few studies that compared regular coffee, decaffeinated coffee, pure caffeine and placebo.


The conclusion from this line of research is that consuming caffeine before a meal results in higher blood sugar and insulin levels following the meal. The implications are:

  • Consuming caffeinated beverages can have a bad effect on blood sugar levels, especially if those beverages also have sugar (i.e. Coke and some other soft drinks).
  • You shouldn’t eat anything sweet with your coffee as the caffeine in coffee will interfere with insulin and result in higher blood sugar and insulin levels.
  • Drinking decaffeinated coffee can reduce post-meal blood sugar and insulin levels. It’s possible that green tea had the same effect.

I would conclude that drinking coffee regularly is probably good for your skin, but you should drink it black without added sugar or coffee, and it’s a good idea not to have anything sweet with your coffee (so keep your hands out of the cookie jar). Switching to decaffeinated coffee could be even better for your skin. You should avoid other caffeinated beverages (such as sodas and energy drinks) as they have caffeine but lack the protective substances found in coffee and tea.

In the grand scheme of things, coffee is probably only a minor factor in acne. Other factors, such as diet, gut issues and stress are likely to have much larger effect than coffee or caffeine.

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About the Author

Seppo Puusa, a.k.a. AcneEinstein shares rational advice about natural and alternative acne treatments. Read more about me and my acne struggles at the page.

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(22) comments

Frederik Ackermann April 11, 2013

Will you write more articles for/with perfect health diet ?

    Seppo April 11, 2013

    Depends on Paul. I would be happy to write more at PHD, just depends whether Paul wants more acne-related articles there.

Kim June 9, 2013

Like your post very much, Seppo! It looks professional and well researched article. Will definitelly subscribe on your blog! What do you think about dark chocolate, say 72% dark? Is it good or bad for the skin? My problem with a coffe is that I cannot drink it without sugar:( What do you think about influence of milk in the cofee? Thanks.

    Seppo June 10, 2013

    Kim, I did a post on chocolate earlier. Chocolate, like caffeine, can increase insulin level. But it’s hard to say where that increase has any real effect on the skin. I don’t think that having some dark chocolate would be bad for your skin.

    Devin Mooers June 24, 2013

    Hey Kim, I eat tons of 80-85% dark chocolate and I’ve noticed no ill effect on my skin. On the coffee front, have you tried Intelligentsia or Blue Bottle coffee? It’s lighter-roasted and incredibly smooth / not bitter, so it’s a lot easier to drink black without the sugar/milk. You can mail order from their websites if you’re interested!

Laura June 9, 2013

Hey there! really like the website!.
4 months ago i decided to change my high bread, pasta, white potatoes and low fruit and veggies diet to fight my acne and i must say i’m clear finally T_T a couple weeks ago i decided to go caveman thanks to Tracy from TLV and, even though it’s till kind of messy, it really improved my skin a lot and i don’t longer have those ugly blackheads on my nose -u-
Regarding the coffee theme (i was actually drinking a cup while reading this lol) i can’t really say if it makes me breakout (i drink the caffeinated type, no sugar, no milk) beacause i always drink it when studyng for my exams (stress) and it’s always during “that time” of the month (hormones) beacause i’m so unlucky that my tests are at the same time :(. So i’m guessing it’s synergic? it’s not even that bad, just a very little pimple or two in my chin
Keep up the good work! (and sorry for the long comment OTL)

    Seppo June 10, 2013

    No point to worry about every single thing in your diet. It’ll just drive you crazy. All the data I’ve seen suggest that coffee itself maybe good for the skin. Caffeine can increase your blood sugar and insulin level but coffee has other substances that counter that. So I wouldn’t worry about it. I should say that I also drink coffee regularly. I’ve quit a few times, but never noticed any positive effect on my life, so I’ve always started drinking it again.

    To be honest, I’m not a big fan of the caveman regimen. It’s based on completely flawed logic, such as that your skin can take care of itself if you would just stopped interfering with all the topical products, when there’s actually a lot of evidence to suggest real abnormalities in acne-prone skin.

    It’s true that people often use too many irritating products that may do more harm than help. In that case, stopping them all would be helpful. But it does NOT follow from that that topical products are bad for your skin. There’s plenty of evidence to support smart use of benzoyl peroxide and topical antioxidants.

    Anyway, if you are already getting good results, then by all means keep up with it. No point to change what’s working :)

      Laura June 10, 2013

      Thanks for answering ^^ Yes! i have actually considered start using a korean lotion my mom got me for my b-day, it’s the most moisturizing thing in the world :o
      I have to admit i ,was reaaally using too many stuff on my skin + the dermatologist recommendation of washing two times a day actually made my skin worse and oilier than ever. Now it’s not oily at all ^^ but tbh i’m afraid of not using anything at all when i can get best results with minimal care xD

        Seppo June 11, 2013

        If you are already getting good results, then no point to change what’s working, right?

Marco July 30, 2013

Hmm i read this article like 10 times but i still dont know if i should drink coffe at all. People claim that coffee raisea cortisol levels and so it causes acne. My problem with these studies is that they only write about the caffein itsself. However im drinking green tea and it contains caff as well and actually helps my skin. maybe because of the slow release of the caffeine. But your article about coffee an acne is by far the best. All the other ones are biased and based on adrenal fatigue BS.

    Seppo July 30, 2013

    Glad to hear that you liked the post. I admit that it’s a bit ambiguous, because the data doesn’t really give good evidence for either way. Coffee has probably minimal, if any, effect on acne. So if you aren’t overtly sensitive to caffeine I wouldn’t worry about coffee.

Devin Mooers December 16, 2013

Hold on a sec, Seppo – on that intervention study you mentioned here, you left out the placebo in your comparison. That seems like the obvious thing to compare to though, doesn’t it? Regular coffee vs. no coffee at all? Instead of regular vs. decaf coffee?

If we compare regular coffee to the placebo instead:
The reported glucose AUC for coffee is 184, and for placebo it’s 176. If you look at the actual curves there, it seems almost obvious that glucose AUC for placebo should actually be lower than for regular coffee, despite their AUC table. They may have miscalculated, or their graph may be slightly off, but either way, the glucose AUC values they reported for regular coffee vs. placebo are within spitting distance of each other (easily explainable by the small number of subjects, only 11). So essentially no net effect on overall glucose from coffee vs. no coffee.

But what you didn’t mention is the insulin AUC! Per the literature, I’d expect insulin to be the variable to look at for determining acne risk, don’t you think? Since insulin is what drives IGF-1 production, excess sebum production, hyperkeratinization, etc.? And insulin AUC was significantly higher after drinking coffee, compared to placebo – 21% higher (26763 vs 22063). And the insulin spike is much higher/sharper, as well.

That study did find that decaf improved glucose tolerance / insulin response versus placebo, and that’s a valid conclusion to draw from it. But you go on to say, “I would conclude that drinking coffee regularly is probably good for your skin” – this seems a little unsupported by the evidence, doesn’t it? Don’t you mean, “I would conclude that drinking decaf coffee regularly is probably good for your skin” is more accurate? Perhaps you were drinking some caffeinated coffee while writing this post as well? :D

    Seppo December 18, 2013

    If you choose to only look at that one small intervention study, then yes, you are correct. But that’s just one small part of the entire data set. As I mentioned at the beginning of the article, several large scale epidemiological studies have shown that coffee reduces insulin resistance and is protective in diabetes and metabolic syndrome. And given that most people drink caffeinated coffee, I’m quite happy with my conclusion. Of course, if you find data that shows otherwise, I’ll be happy to take a look at it.

      Devin Mooers December 18, 2013

      Did you see my reply to your comment on my blog? I went through a good chunk of other studies there, and also wrote some about possible confounding factors in the epidemiological study you cited. Bottom line, I don’t think the science is conclusive one way or the other – short term intervention studies show insulin resistance and worsened glucose tolerance with caffeinated coffee, long-term epidemiological studies show lowered diabetes / CVD risk. Who’s right? I trust the short-term studies, myself, as well as the fact that I get elevated heart rate and general nervousness/anxiety when drinking coffee. Took me a long time to come to terms with that. I’ll stand by my conclusion, too! Agree to disagree on this one. :)

        Seppo December 18, 2013

        Yep, saw and replied there also. Agree to disagree since I don’t agree with your interpretation of the studies. Epidemiological studies may have confounding factors, but it doesn’t mean it’s wrong, especially since there are other studies that point to the same conclusion. It’s true that short term intervention studies show worse insulin response than placebo, but the effect seems very small and doesn’t say anything about long term effects, and epidemiological studies suggest long term effects are positive.

Prof Bob January 4, 2014

Not quite sure from the above discussion whether there might be some people who are more sensitive to caffeine and so would better avoid green tea as we’ll – as although this has much less than coffee it adds up with 10 cups a day ?

    Devin Mooers January 5, 2014

    10 cups a day could be 500mg of caffeine, depending on the green tea! That’s a hefty amount. I really do think some people tolerate caffeine better, and they’re the ones that end up drinking 5 cups a day with no problems. I personally start to get slightly irritable and nervous/anxious with long term coffee drinking (even 1/2 – 1 cup a day). I’m betting on genetic / epigenetic differences in how caffeine is processed in the body.

    Seppo January 6, 2014

    I hesitate the answer yes here. Mainly because I know there are acne patients who take food phobias to extreme and avoid any food that has even the slightest chance of causing acne.

    But yes, people who are very sensitive to caffeine might want to avoid teas also. That said, I find it hard to believe that even such people would get acne from drinking green tea. They may suffer other negative effects of caffeine, though.

      Prof Bob January 7, 2014

      I have noticed my acne getting worse as I drink more coffee (although of course this could also be coincidence) – but don’t have any ‘jittery’ effects. So I’m more concerned about the negative impact of caffeine on acne than I am on effects it might have on my mental state. There are low caffeine EGCG supplements, e.g. NowFoods via iHerb, which claims only 4 mg caffeine with 200mg EGCG in a 400mg capsule. Presumably I should still get the benefits of EGCG through a capsule – most of the reported studies seem to use capsules as a delivery route anyway?

        Seppo January 8, 2014

        Yes, you could get the benefits of ‘green tea’ from a supplement. However, I do not think green tea is a miracle food. It’s a good source of antioxidants and can have skin benefits. I’m just not sure those benefits are large enough to justify supplementation. Green tea extract supplements have been linked to liver problems, but it’s hard to say whether those cases are due to contaminated products or because of something in green tea itself. Because of almost total lack of regulation, I’m always a little wary of supplements.

        Devin Mooers January 9, 2014

        I saw a study recently on herbal supplements that found pretty appalling purity measurements. I’d say drink a few cups of green tea a day if you like it, but I’m with Seppo, no need to supplement things like green tea / EGCG.

          Prof Bob January 11, 2014

          Thanks – that saves some money I don’t need to spend on supplements!

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