I use piroctone olamine shampoo for my hair loss and seb derm and am constantly searching for other shampoos to rotate with it that may potentially help with either problem. Tea tree oil sounds like a good bet, so I bought some of the pure oil at the store to add to a standard non-irritating shampoo. All the studies that say it is beneficial used a 5% tea tree oil shampoo. I've searched the boards and the internet but could not find out how many drops equal 5% in a certain volume of shampoo. Does anyone have any idea?