Should You Blow Dry Wet Or Dry? A Scientific Approach

Have you heard of bubble hair? As the name suggests, it is literally bubbles of air forming in hair. This happens when wet/damp hair is in contact with a heating tool (straightening iron, curling iron or blow dryer) and water inside hair heats up to its boiling point (circa 100°C/212F). Heating tools range in temperature with a cool level at 30°C/86F and a high level at over 200°C/392F but not all have accurate gauges making it very easy to end up with bubble hair if you start blow drying or heat straightening on damp hair. The bubbles can usually be felt as irregularities that were not previously present and the hair usually ends up becoming very brittle.

However many hairdressers do successfully use blow dryers on wet or damp hair and even say it is better for kinkier textures. So what is the deal, is it better to go for wet hair after all or are there advantages to using heat on dry hair?

1. Heat Treating Wet/Damp Hair
Pros
— Wet hair is weaker but more flexible for manipulation.

Cons
— Risk of bubble hair if high heat is used or the appliance is overheats while in contact with hair (BJD, pp 901–903, 1994).
— There is more external structural damage to hair compared to using heat on dry hair (J Cosmet Sci, pp 15–27, 2011).
— Repeated cycles of wetting hair and blow drying can induce cuticle cracks (J Cosmet Sci, pp 141–153, 1998).

2. Heat Treating Dry Hair
Pros
— There is less external structural damage to the hair compared to using heat on wet hair (J Cosmet Sci, pp 265–282, 2011).
— Bubble hair is less likely (unless you use a heat protectant that is water based and therefore a water source)
— Hair does not change in terms of rigidity unlike with wet hair that has been heat-treated that becomes less rigid post-treatment (J Cosmet Sci, pp 15–27, 2011).

Cons
— Dry hair is stronger but less flexible making it susceptible to breakage.
— For kinkier textures and tight curls, some amount of stretching via another method may be necessary before attempting to apply heat.

General Notes
— It is good practice to use a heat protectant on dry or damp hair to protect from some elements of heat damage (J Cosmet Sci, pp 265–282, 2011).
— All heat-treated hair wet or dry sustains some amount of chemical damage notably loss of an amino acid called tryptophan (J Cosmet Sci, pp 15–27, 2011).
— This article is for the girls (maybe a few guys out there) who do like and whose hair can take heat. For some us, heat is a no-no, which is why you should look to African threading if you want a heat free blow out look!

Do you prefer to blow-dry your hair while wet or dry? Sound off in the comments below!