However, I think this one takes the biscuit it's the, er ... "personal product" that also works as a hair serum, and heat-styling protector. Would you? Could you?
Warning: while the link is safe for work (it's from HQ Hair) the product itself might not be something you want on your work internet history ... Many thanks to @muddlinleigh for the link!
What are some of your favourite double-duty products?