Does Rinsing Hair With Cold Water Affect Hair Growth?'

Name: Jenny

Question: I read online that using cold water at the end of washing your hair made your hair shinier, but today I read something that said using cold water could contract the blood vessels in your scalp and negatively affect hair growth. What do you think about using cold water at the end of a hair wash? Does it affect hair growth?

Answer: Hi, Jenny. Thank you for checking this with us as there are many hair myths and lots of information about hair growth online that comes from non-professional sources and is not necessarily true.

Cold water doesn’t close the cuticles. When the hair is wet, the cuticle layer will be open regardless of the temperature. However, some people believe that cold water lifts the cuticle scales less than hot water.  Either way, once the hair dries, the cuticle scales will close.

If the hair is porous, cuticle scales may be missing and the hair can look dry, dull and frizzy, regardless what water temperature is used to rinse the hair. In healthy hair cuticle scales close smoothly and, as the hair reflects light, it will appear shiny.

Whilst Afro textured hair is the most likely to be porous, any hair type can be porous though Asian hair is the least likely to be affected. Over-processing with chemicals or heat is the biggest contributor to hair porosity, regardless of hair type. You can tell if your hair is porous or not by taking a strand between your thumb and index finger, then sliding your fingers along it from root to end. The hair should feels smooth; if it feels rough, there may be swelling of the cortex or longitudinal splitting of the hair shaft or any other form of damage. This would mean the hair is porous.

Straight hair tends to look shinier than curly hair because of the way it reflects light, but it doesn’t necessarily mean that it is healthier. It is simply because curls cause shadows and curly hair therefore has a naturally less shiny appearance.

Some people like to alternate hot and cold water in the shower as they believe this will increase the blood circulation. Also, some like finishing a shower with cold water as it will constrict the pores of the skin making it appear clearer. In terms of hair growth, this wouldn’t have a significant effect either way.

I would say, with regards to how shiny the hair is or can be, this depends on the health of the hair and the products used on the hair, rather than the water temperature used when rinsing.