The hair oil you should avoid is mineral oil.
Mineral oil, often disguised on ingredient lists as paraffin wax or petroleum, can lead to undesirable buildup on your hair strands. This buildup can ultimately trigger hair fall. Therefore, carefully check the ingredient list of any hair care product, especially hair oils, to ensure it doesn't contain mineral oil or its common aliases. This is important for maintaining healthy hair and preventing potential hair loss issues related to product buildup.