The perception of hair dryness -Is it moisture related?

Many of us suffer from hair dryness, or so we think. But is it only due to a lack of moisture? The cause for dryness in damaged hair is different than in virgin/minimally damaged hair. Here’s why.

Dryness in Virgin/ Minimally damaged hair

Hair can absorb up to 32% water. However studies show that the amount of moisture that stays in the hair after it dries is dependent primarily on the humidity in your environment. If the humidity is low your water content will also be low and likewise in a high humidity environment your water content is high. In fact, in virgin/ minimally damaged hair, the moisture level tends to equilibrate accordingly.

Interestingly research has shown that the lipid (fat) composition of the hair governs the dryness and oiliness of hair. Having more of one component and less of another can dramatically change how the hair feels naturally.

Additionally, the texture of the hair might also influence how we perceive dryness. For example curly virgin hair usually complains of dryness more than straight virgin hair.

In an experiment that I personally did with african american hair tresses, I was surprised to find that after flat-ironing the hair straight, it felt smooth and ‘moisturized’. Bear in mind that in the curly/coily frizzy state, the hair felt ‘dry’ and crunchy. Ironically, by flat-ironing I was actually removing the water content of the hair, but yet the hair felt great. This could potentially be due to the heat causing the lipids of the hair fibers to melt thereby distributing more evenly along the hair fibers as I was flat-ironing. So this made me wonder. Is ‘dryness’ entirely about moisture? It doesn’t seem to be the case.

One could say that dryness in virgin/ minimally damaged hair refers mostly the lack of certain lipids (or uneven distribution of lipids in textured hair). Restoring the oils and fats of the hair with products can help keep the hair soft, malleable, and smooth thereby attributing the feeling of being moisturized.

Obviously the hair’s porosity varies from person to person, but if the hair is not that damaged and close to virgin hair, they should still have a fair amount of moisture present in the fiber.

Dryness in Damaged Hair

Dryness in damaged hair is whole different story. In damaged hair, the integrity of the cuticles have been compromised and in some cases they might no longer be present on the hair fibers. In this case, the hair absorbs water faster than virgin hair but also loses the water very rapidly upon drying causing it to become crunchy and rigid. Damaged hair is thus unable to regulate its moisture content as it should.

Additionally, the lack of cuticles or presence of damaged cuticles means that the lipids are also missing or present in low amounts. The combined effects of low moisture content and low lipid content gives damaged hair not only the feel of extreme dryness but also the look of being dry. Usually this type of dryness is also associated with dullness/ lack of shine.


Chemical and Physical Behavior of Human Hair by Robbins

Cosmetics and Toiletries, Science applied. Glycolic acid no longer just for skin- changing the internal properties of hair by Evans et al.

Originally published at on October 21, 2015.