Usually we see that many saints and Vaishnavas around us wear sandalwood and tilak. And we think that maybe only they should wear sandalwood and tilak. This idea , how much is it based on truth ? Let's not know in the light of scripture. Sri Chaitanya Mahaprabhu himself has said- If there is no tilak on the forehead of Bipra. He says in the Vedas resembling a forehead crematorium. The **** says , buy brother , your forehead. I don't see Tilak , what is the reason for this ? In the Padma Purana, Srivagavan says to Brahma - Madbhakto dharayennityamurdhvapundrang vyapaham. " -O Brahma , my devotee will wear the fear-killing Urdhvapundrang tilak every day for my love or for his own good and for his own protection. Srinivasan Muni's statement is that- Byarthang bhavati tatsarva murdhva pundrang bina kritam. -Urdhvangpundrang does not hold tilak , his yajna donation , austerities , home , study of Vedas , father tarpan, etc., any action performed fails. He further said, Note: -Urdhvapundra Tilak-free human body resembles a crematorium. That person is not worthy of visitation (Padmapuran). Sohapi abandoned the fire and tried to get rid of it. " - O angels! Whose forehead will see Gopichandan Pundra Tilak , like burning embers will abandon him from afar with utmost care. Because such a person is unworthy of hellish suffering. Many people do evening salutations but do not tilak. Seeing such a person , Sri Chaitanya Mahaprabhu said , your evening today is barren. The author of Sri Chaitanyamangal , Srilochana Das Tagore, sang : Vishnu Purana Balchen Vishnu Dev Narad who ? Narad, my favorite devotee is the one who always wears sandalwood on his forehead while chanting my Guna Kirtan. Applying holy sandalwood on the body destroys sin and evil energy !! What is the scientific explanation ? Scientists can find out by researching that applying sandalwood on the forehead keeps the brain cool , increases endurance and keeps the mind calm !!