Short answer
Yes. Using a safe, lawful product to help your beard grow is treatment and grooming, which is allowed. It is not required, though: a man whose beard is naturally thin or patchy has no sin and only needs to keep what Allah grows.
Treating hair loss or thin growth is permissible (mubah) as long as the product is safe and contains nothing impure. The synthetic alcohol in hair solutions does not make them impure in the Hanafi view explained by Mufti Taqi Usmani.
The four schools agree on this.
Explanation
The Prophet ﷺ said that Allah has not sent down any disease without sending down a cure for it, and he told people to seek treatment. Beard loss from a condition such as alopecia is an illness that may be treated. A naturally light beard is not an illness, but helping it grow is lawful grooming, much like oiling and combing it.
- Minoxidil and similar solutions: allowed, but they can have side effects, so follow a doctor's advice. Their ethanol and propylene glycol are not made from grapes or dates, so in the Hanafi school they are not impure; see is perfume with alcohol haram.
- Oils, serums and supplements: allowed if the ingredients are halal and safe.
- Microneedling: allowed; see is microneedling haram.
- Beard transplant: moving your own hair is allowed; see is a hair transplant haram.
Fillers and pens. Tinted beard fillers and fibres sit on the skin as a layer. Wash them off before wudu and ghusl, and do not let them become a made-up look.
No pressure. Some men simply have thin beards, and the Companions included men with little facial hair. You are not sinning, and you do not have to buy anything. What is asked of you is to leave what grows and keep it clean. See the Sunnah length of the beard.
The evidence
Quran, Surah Al-A'raaf 7:32
قُلْ مَنْ حَرَّمَ زِينَةَ ٱللَّهِ ٱلَّتِىٓ أَخْرَجَ لِعِبَادِهِۦ وَٱلطَّيِّبَٰتِ مِنَ ٱلرِّزْقِ ۚ قُلْ هِىَ لِلَّذِينَ ءَامَنُوا۟ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا خَالِصَةًۭ يَوْمَ ٱلْقِيَٰمَةِ ۗ كَذَٰلِكَ نُفَصِّلُ ٱلْءَايَٰتِ لِقَوْمٍۢ يَعْلَمُونَ ﴿٣٢﴾
Say, "Who has forbidden the adornment of Allah which He has produced for His servants and the good [lawful] things of provision?" Say, "They are for those who believe during the worldly life [but] exclusively for them on the Day of Resurrection." Thus do We detail the verses for a people who know.
Adornment and good things are lawful unless Allah has forbidden them.
Sahih al-Bukhari 5678
Sahih... ما أنزل الله داء إلا أنزل له شفاء ...
"Allah has not sent down any disease without sending down a cure for it."
Seeking treatment is lawful.
Sunan Abi Dawud 3855
Graded sahih... تداووا فإن الله لم يضع داء إلا وضع له دواء ...
"Seek treatment, for Allah has not made a disease without making a remedy for it."
A direct instruction to seek treatment.
Where the ruling is recorded
- al-Fatawa al-Hindiyya, Kitab al-Karahiyya, chapter on medical treatment. Treatment with lawful means is permitted.
- Fiqhi Maqalat (Mufti Taqi Usmani), Article on alcohol in medicines and perfumes. Synthetic and grain alcohol in products is not impure in the Hanafi view he relies on.
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.