There are a number of reasons why your hair always feels greasy. Your scalp may produce an overabundance of sebum. Sebum is necessary, but an overabundance will cause oily, greasy hair, clogged pores and acne. Make sure you are using the correct shampoo and conditioner, specifically formulated to combat an oily scalp. Don't over shampoo. Over shampooing will strip your hair of it natural oils, causing your scalp to produce more sebum than is necessary. When you do shampoo, be sure to clean your scalp thoroughly, often two to three shampoos are necessary, especially if you are using a sulfate-free shampoo. Completely rinse out your conditioner until the water runs clear. Conditioner residue to make your hair look and feel greasy immediately after washing. Always do a final cold rinse to close down the pores on your scalp. This will help stop the overproduction of oils. Use the right styling products for an oily scalp and hair, volumizers, texturizers and root lifts are the best. Don't touch your hair too much. When you touch your hair, oils from your hands will transfer to your hair, making your hair look and feel greasy.