Friday, May 23, 2014

Question of the Week: Are coffee wraps legit?

Hey, strangers.  It's been a while, huh? 

So, the blog kind of got away from me, basically for two reasons:
  • The hypomanic high that propelled me through February and March and the first part of April gave way, as it inevitably had to, to some sluggish, lethargic, perpetually-exhausted unpleasantness.  Whereas I had been enjoying inordinate amounts of free time in the first few months–because I only needed to sleep 4 hours–suddenly most of my unaccounted-for moments were going to naps.
  • I started helping mod the /r/HaircareScience board.  I noticed that some of the writing that I used to be doing for the blog was now being done as comments on the board.  Which got me thinking...why not pull some of my longer, more thoroughly-researched pieces back over here?  Which brings us to today: redditor /u/mrs_shrew kindly agreed to have her original question replicated here with my response.  You can click here to visit the entire thread on Reddit (consider joining us on the board!).  :I thought about rewriting just my response into more of an essay type thing, but I think the Q&A format is fun and easy to get into, plus...the May doldrums are still hovering around and I'm feeling lazy.  So!  Let's take a look at our question, shall we?


Mrs. Shrew has a question about the humble cuppa joe:

Has anyone tried a coffee hair wrap?

I read somewhere once that the caffeine stimulates there any truth to this? 

I thought I would try it so I made a cup of strong coffee (3spoons of instant in half a teacup) and soaked my hair for a couple of hours and it seemed to make it thicker or was that just the shafts being swollen?


This was a really interesting question! I did a quick search of the subreddit for "caffeine" and was surprised to see that it apparently hasn't been discussed much.

Here's an interesting in vitro study of caffeine which tested hair follicles that were taken from men with male pattern balding. Caffeine seems to have some positive effect on hair growth in this study. I think it's really important that these are follicles from men with AGA--that is, hair follicles that are probably not growing "normally". As yet, I can't find any studies that show that caffeine accelerates growth in normal hair.

This particular study was done on follicles themselves which raised another question for me: does caffeine applied to the scalp penetrate to a level where it would be useful? Hair follicles seem to be a relatively good pathway for caffeine absorption: this in vivo study found caffeine in the blood of test subjects five minutes after topical application, which is cool. Also interestingly, they find the highest level of caffeine penetration one hour after application, so coffee hair wrappers apparently wouldn't need to leave it in for ages and ages.

So in terms of whether there's any truth to caffeine stimulating growth....maybe. AGA-patient hair shown positive effects in at least one study. I personally can't find any data to show that it does anything to normally growing hair, however, at least at the moment. I think we have to assume "no" until proven otherwise.  As a general rule, you can't make hair that's growing healthily grow any faster: hair growth rates, anagen phase length, and thickness are more or less genetically determined and as long as there are no problems, you can't really improve these. Coffee seems to be a pretty imprecise way of getting caffeine onto your scalp, but some measure of penetration is possible. Whether it's enough caffeine is another outstanding question.

I can't tell from your post if you put the coffee on your scalp, or just the lengths of your hair [edit: OP clarified in her reply comment that she was, indeed, applying it to the scalp]. Any potential for caffeine to affect growth is probably only present if it's applied to the scalp. The thickness question is also interesting to me; I can't find any scientific research on that at all, but coffee definitely has the potential to stain hair, so the thickness could be from the stain, similar to henna, though not permanent. That's would be my guess, but a "guess" is really all it is.