As far as Islamic Shari`ah is concerned, the issue of using bristle brushes made from boar or pig by-products for non-food purposes has been a matter of disagreement between the Muslim scholars. However, it is better for a Muslim to steer clear of using such bristle brushes since there is an alternative in the market.
The issue of using pig by-products for non-food purposes has been a matter of disagreement between the Muslim scholars. Some of them view it haram while others view it permissible in specific cases, such as tanning pig leather, which, they argue, removes its impurity.
Both positions are Islamically correct. The way we see it is that, since hairbrush bristles are not tanned leather, and since there is an alternative in the market (from synthetic origin), it is better to choose the alternative. The same applies for other pig by-products such as soaps, shampoos…etc.