Sister Scientist: "Hot water is more effective in helping to remove dirt, oil, and build-up from the hair, but it can also remove the natural oils your hair produces to stay soft and moisturized. Use hot water in moderation."
What's the best temperature for washing your hair?
Sister Scientist: "Start with hot water when shampooing the hair to help open the pores on the scalp to release dirt and oil, and also enhance the studying of your shampoo. Then reduce the temperature of the water to warm on the next shampoo or rinse."
Does cold water really seal the cuticle?
Sister Scientist: "Contrary to popular belief, there is not enough scientific evidence that supports the theory that cold water seals the hair cuticle. However, this doesn’t mean that the perceived 'sealing' benefits are completely false. Cold water may not physically seal the cuticle, but rather, I believe that people are observing the difference between the effects of steam and water on the hair."
How does steam affect the hair?
Sister Scientist: "Steam often results from using hot water in small spaces (i.e. the shower). The distance between water molecules that exists in a gaseous state (i.e. steam) is much larger than the distance between liquid water molecules. Gas molecules move more freely and are highly compressible, allowing it to diffuse or penetrate the cuticle layer faster. This could give the perception that hot water opens the cuticle, and cooler water seals it. However, all temperatures of water can penetrate and swell the hair shaft, raising the cuticle."
What's the best way to smooth your cuticle and prevent frizz?
Sister Scientist: "The best way to ensure the cuticle layer is nice and smooth is to make sure you use a great conditioner, no matter what the temperature of the water is."
Now that you know the science behind hot water and cold water for your natural hair, which one will you use on your next wash day?