Can Muslim men put henna on their hands?

It depends on the part and the reason. Muslim men may use henna on their hair and beard, and it is actually a sunnah way to change gray hair. Henna on the hands and feet is fine for a medical need, but many scholars discourage it as decoration because it is seen as women's adornment. Some allow it where it is an ordinary custom for men, such as a groom's henna night.

Henna for hair and beard is a sunnah

The Prophet ﷺ said: "Indeed the best of what the gray may be changed with is henna and katam" (Jami at-Tirmidhi 1753). Katam is a plant dye that gives a darker, brownish shade when mixed with henna. Men have used this mix on their hair and beards ever since. Henna alone gives an orange-red tone. See Can I make wudu with hair dye or henna?

Henna for pain or injury

Henna was also used as a simple remedy. Salma, a servant of the Prophet ﷺ, said that when someone complained of pain in his legs, he told them to dye them with henna (Sunan Abi Dawud 3858). So a man who applies henna for a medical or practical reason has no problem. Cooling or soothing the skin is a need, not a fashion statement.

Decorative henna on the hands

This is where scholars differ. The Prophet ﷺ cursed men who imitate women (Sahih al-Bukhari 5885). In most cultures, patterned henna on hands and feet is traditionally women's adornment. For that reason many scholars discourage it for men, especially detailed designs, and prefer that men keep henna to the hair and beard.

Other scholars say the imitation concern depends on local custom (urf). In some regions, grooms and other men wear henna at weddings, and a simple, plain stain there is not seen as copying women. If you want to join a groom's henna night, a small, plain mark is the cautious way to do it.

Custom, not sunnah

Henna on the hands for Eid or weddings is a cultural tradition, not a sunnah in itself. That means you don't lose reward by skipping it. If you do it, keep the intention simple, choose a plain pattern and avoid anything that looks clearly feminine. For women's henna, see Can I wear henna as a Muslim woman?

Henna, wudu and safety

Stain: dried henna colors the skin and doesn't block water, so wudu and prayer are valid.
Wet paste: remove it before wudu, because paste sits on top of the skin.
"Black henna": it can contain a chemical that burns the skin. Use natural henna only, which is orange to reddish-brown, and test a small patch first.

Key points

Henna on the hair and beard is a sunnah way to change gray.
Henna for pain or injury is fine for men.
Decorative henna on the hands is discouraged by many scholars.
Natural henna doesn't affect wudu once the paste is washed off.

Tip: For a natural dark-brown beard, mix henna with katam, which many Muslim shops sell ready-made, and do a patch test first.