Hair cuticles are hard, downward-pointing scales that form the outer layer of hair strands. As the "National Journal of Homeopathy" notes, hair cuticles are "appendages of the epidermis." Human hair cuticles normally lie flat but can sometimes stick up, causing rough-looking hair. Chemicals in hair dye, hot water, too much moisture and wind and cold weather are some of the things that make hair cuticles stick up. Learning tricks to seal hair cuticles is the secret to shiny, smooth hair.
Many people recommend rinsing hair with cold water to improve shine and reduce frizz, because cold water helps flatten and seal hair cuticles. Use a cool to cold water rinse as the last thing you do before exiting the shower.
When blow-drying hair, use a nozzle and point the hair dryer down toward the end of the hair. This technique flattens hair cuticles. Use the cool air setting on the blow dryer as the last step to encourage sealing of hair cuticles.
Hair has an average pH of 5. Shampoos can sometimes cause the pH of hair to become unbalanced, contributing to rougher cuticles. An apple cider vinegar rinse is one way to balance the pH of hair. Use 1/2 tbsp. to 1 tbsp. apple cider vinegar mixed with 1 cup water after shampooing and pour the mixture on your hair, avoiding the scalp. It's up to you whether you rinse the apple cider vinegar mixture from your hair or not, but the vinegar smell should dissipate once your hair dries.
Hair often contains buildup from products, shampoo and conditioner. Buildup lifts the cuticle up, not allowing it to seal. Use a clarifying or deep-cleaning shampoo on hair once a week or so to remove buildup on hair.
Some oils have the extra benefit of sealing hair cuticles. The human head naturally produces its own oil -- sebum -- which protects hair. Frequent shampooing washes away sebum. Shampoo hair less -- ideally once or twice a week -- and brush hair every day with a boar bristle brush to help the sebum coat all of your hair. To add a little extra oil if needed, especially in winter or dry climates, use olive oil. Put one or two drops of olive oil on your fingers and distribute the oil through the ends and bottom sections of your hair.