Short answer
No. In the Hanafi school the pig is impure in its whole body, including its hair, so a brush made of boar bristles should not be used when other brushes are easy to find. Earlier scholars allowed pig bristle only to cobblers out of real need. The Maliki school differs: it holds that hair shorn from any animal, even a pig, is pure.
The pig is najis al-'ayn (impure in its essence), and the relied-upon view is that its hair is impure too. Using it is not permitted except in real necessity, which the classical texts allowed for leather stitchers. With plenty of alternatives today, boar bristle hairbrushes, beard brushes and makeup brushes should not be used.
Other madhhabs
- Maliki
- Hair shorn from any animal, even a pig, is pure in the relied-upon Maliki view, so a boar bristle brush is not impure for them.
Explanation
The Quran calls the flesh of swine impure, and the Prophet ﷺ forbade selling pigs along with wine, carrion and idols. The Hanafi scholars read these together: the pig is impure in its whole being, so its meat, fat, skin and hair cannot be made pure by tanning or anything else. That is why pigskin is not used and why a sale of pig hair is invalid in the Hanafi books. The Shafi'i and Hanbali schools agree that pig hair is impure.
The old exception. Cobblers in the past sewed leather with pig bristles because nothing else was stiff enough. The Hanafi jurists allowed them to use it for that need alone. Today nylon, plant fibres and the hair of other animals do every job a boar bristle does, so the need has gone.
What this means for brushes. Hairbrushes, beard brushes, shaving brushes and makeup brushes labelled "boar bristle" or "100% boar" are pig hair, so avoid buying them. Good alternatives are nylon, tampico or agave fibre, goat hair and horse hair. In the Hanafi school the hair of every animal other than the pig is pure, even if the animal was not slaughtered, because hair has no life in it.
If you already have one. Dry hair that touched a dry brush does not become impure. If you brushed wet hair or a wet beard with it, wash that hair before you pray. Then replace the brush. Many brushes mix boar and nylon, so read the label or ask the seller before you buy.
For other animal products, see can Muslims wear leather and soap made with animal fat.
The evidence
Quran, Surah Al-An'aam 6:145
قُل لَّآ أَجِدُ فِى مَآ أُوحِىَ إِلَىَّ مُحَرَّمًا عَلَىٰ طَاعِمٍۢ يَطْعَمُهُۥٓ إِلَّآ أَن يَكُونَ مَيْتَةً أَوْ دَمًۭا مَّسْفُوحًا أَوْ لَحْمَ خِنزِيرٍۢ فَإِنَّهُۥ رِجْسٌ أَوْ فِسْقًا أُهِلَّ لِغَيْرِ ٱللَّهِ بِهِۦ ۚ فَمَنِ ٱضْطُرَّ غَيْرَ بَاغٍۢ وَلَا عَادٍۢ فَإِنَّ رَبَّكَ غَفُورٌۭ رَّحِيمٌۭ ﴿١٤٥﴾
Say, "I do not find within that which was revealed to me [anything] forbidden to one who would eat it unless it be a dead animal or blood spilled out or the flesh of swine - for indeed, it is impure - or it be [that slaughtered in] disobedience, dedicated to other than Allah. But whoever is forced [by necessity], neither desiring [it] nor transgressing [its limit], then indeed, your Lord is Forgiving and Merciful."
The Quran describes the pig as impure, which the Hanafis apply to all of its parts.
Sahih al-Bukhari 2236
Sahih... إن الله ورسوله حرم بيع الخمر والميتة والخنزير والأصنام ...
"Allah and His Messenger have forbidden the sale of wine, carrion, pigs and idols."
The pig is listed with things that have no lawful use or value, so its parts are not traded or used.
Where the ruling is recorded
- al-Hidaya, Kitab al-Buyu', chapter on invalid sales. Selling pig hair is invalid because the pig is impure in essence; use by leather stitchers is allowed out of need.
- al-Durr al-Mukhtar with Radd al-Muhtar, Kitab al-Taharah, chapter on water. Parts of an animal that have no life, such as hair and bone, are pure, except those of the pig.
- Mukhtasar Khalil with al-Sharh al-Kabir, Kitab al-Taharah, section on pure and impure things. The Maliki view that shorn hair is pure, even from a pig.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.