# Caffeinated Soap - Is it for real?

**URL:** <https://boards.straightdope.com/t/caffeinated-soap-is-it-for-real/117765>\
**Category:** Factual Questions\
**Created:** [July 7, 2002, 10:12am UTC](https://boards.straightdope.com/t/caffeinated-soap-is-it-for-real/117765 "2002-07-07T10:12:41Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Theios](https://avatars.discourse-cdn.com/v4/letter/t/e8c25b/32.png) [@Theios](https://boards.straightdope.com/u/Theios)\
**Post date:** [July 7, 2002, 10:12am UTC](https://boards.straightdope.com/t/caffeinated-soap-is-it-for-real/117765/1 "2002-07-07T10:12:41Z")

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While browsing [ThinkGeek.com](http://ThinkGeek.com), I came across a caffeinated soap called “Shower Shock”. They claim that the caffeine is absorbed through the skin as you wash. Is this possible?

Although I highly doubt that you can absorb caffeine though the skin this way, I now own a bar for the sole purpose of freaking out house guests. 😃  
You can view the product at [http://www.thinkgeek.com/stuff/caffeine/5a65.shtml](http://www.thinkgeek.com/stuff/caffeine/5a65.shtml) .

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**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\
**Post date:** [July 7, 2002, 3:14pm UTC](https://boards.straightdope.com/t/caffeinated-soap-is-it-for-real/117765/2 "2002-07-07T15:14:05Z")

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Apparently, there is some validity in the idea that caffeine can be absorbed through the skin:

[http://www.pharma.tno.nl/Product.cfm?PShID=650&DivID=9](http://www.pharma.tno.nl/Product.cfm?PShID=650&DivID=9)

> [@](#):
>
> Caffeine, a substance with good penetrating capability, has been used as a model compound in many in vitro skin penetration studies.

You will note, however, that the sample study described there involves a 4 hour application. I have my doubts that you can get anything but a boost to your imagination from caffeine infused soap which you wash off again immediately, and probably doesn’t contain that high a concentration to begin with.

The soap also contains peppermint oil, which may produce a noticeable effect, that one might interpret as “invigorating” if one wished.