Answered by: Shaykh Ahmed bin Mohamed Umarji
I tend to sweat sometimes when sleeping. This causes my underwear to become slightly wet in some areas. Not much towards the front but more on the side between my inner thigh and private area and maybe slightly further upon these sides. It gives me doubts when waking whether I need to perform ghusl even when I know I have not had any kind of dream and I am sure it is due to sweat. Do I need to ignore these thoughts, or would I need to perform ghusl?
In the name of Allah, the Most Gracious, the Most Merciful
When one has the conviction that the wetness is sweat and not due to a wet dream, the ghusl will not be compulsory. This is due to sweat not being from amongst those things that render a ghusl compulsory.
Only Allah knows best
Written by Shaykh Ahmed bin Mohamed Umarji
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Nurul Idhaah, Page 27, Zam Zam Publishers