What is the ruling on using snake or viper oil for hair? Is it considered impure like carrion? And is it permissible to use it as a treatment to thicken and lengthen hair?

The majority of scholars are of the opinion that eating snakes and serpents is forbidden, and therefore, their carcasses are impure (najis). It is not permissible to use impure snake oil on the body except in cases of urgent necessity, with the obligation to wash it off before every prayer, because impurity invalidates prayer. Some scholars have permitted benefiting from the fat of a carcass for purposes other than eating or applying it to the human body. Others have permitted treating oneself with impure substances out of necessity, provided it is not through ingestion, and with the condition that it is washed off before prayer.