Also, the manufacturer can legally only make certain claims for the product.
They can't claim the stuff will actually make your hair healthier, because, as has been pointed out, hair is already dead past the roots.

So making it 'look' healthy is the best they can offer.
(Juan Quar is clinging to her front teeth on, Sat 10 Apr 2010, 11:55, 1 reply)

Exactly
It's also the same reason Cleaning agents will always leave one computer generated germ left on the kitchen side, or the visual plumping of the skin missing a tiny part of the face
(Ludacrust alliterated your monstrously magnanimous mother, Sun 11 Apr 2010, 22:19, closed)