Tip # 6 - STOP HAIR STRETCH AND USE HEAT SOURCES

The exposure of hair to heat can result in structural damage. This is not surprising since many heat styling devices can reach temperatures as high as 230ºC.

The excessive styling heat on a hair fibre changes its natural pattern, becoming irreversible when reaching the hair protein’s denaturation temperature.

To straighten or curl your hair temporarily requires utensils such as an airdryer, straightener/flat irons, hot hair brush and it only lasts until the next wash.

What happens when you straighten your hair?

To get your hair straighten, you need heat to shape it as you wish.

Temporary straightening or waving requires techniques such as dryer, flat iron, hot comb and lasts only until the next wash. These tools denature the bonds in keratin which allow you to re-shape your hair. As your hair cools down, new bonds that lock your hair in that shape are formed.

To return to its natural shape, the hair then needs to be dampened in order to break the hydrogen bonds of the keratin.

Heat tools are commonly used in curly hair and can cause hair damage such as roughness, dryness and loss of hair colour and natural shine. Your hair might easily break when combed, become very frizz and tangled. The more heat tools you use, the more damage your hair is going to experience.

Some scientific studies show that heat causes cracks/damage in the cuticle and protein loss in hair, making the hair more porous and dehydrated.

Straighten your hair: Dry or Wet?

You can see from these pictures on the left that blow drying/straightening on dry hair, causes various types of chemical and structural damage. However, on wet hair, the same heat utensils cause the same kind of chemical damage but with a much higher structural damage, causing irreversible changes on the physical properties of hair.

This comes from the quick evaporation of water from the hair, as you can see in the picture, by straightening on dried hair, flat irons will cause less damage to the hair fiber than if you do the same with wet hair.

In these pictures on the right, we can take a look at the surface of a hair fiber in the microscope. The pictures compare the level of damage of hair. The first picture is a healthy hair without any treatment. The second image is a hair that just washed with shampoo and dried the hair naturally. In the third picture the hair was washed with shampoo and dried with an airdryer 60 seconds at a distance 15 cm. In the fourth picture the hair was washed with shampoo and dried with an airdryer 30 seconds at a distance of 10cm. In the last picture the hair was washed with shampoo and airdried by 15 seconds at a distance 5 centimeters.

These cracks occur because of the rapid change of wet hair to dry.

As you can see, drying hair with an airdryer too close to the hair root causes enormous damage to the hair fiber. As you know, this is something that happens whenever we go to the hairdresser: drying at high temperatures and very close to the hair, in order to dry it quick and have more or less acceptable results, so you can imagine the damage this causes. The damage is even greater if you dry it very fast at high temperatures.

Is there a way to prevent this?

A regular deep conditioning mask containing protein (used to reconstruct hair) can help in the short term, but on the long-term, the only way to remove the damage from excess heat is by cutting hair ends or make a hair transition.

There is no better way to prevent this heat damage, but some studies suggest that using an airdryer/diffuser at a distance of 15cm with continuous movements at the lowest temperature, cause less damage. You can also choose to use heat protection products in the hair, but be careful, because many of these products rely on Silicones to reach this goal.

Information and pictures of scientific articles:

Yoonhee, L., Kim, Y., Hye-Jin, H., Pi, L., Jin, X. and Lee, W. (2011). Hair Shaft Damage from Heat and Drying Time of Hair Dryer. [PDF] http://dx.doi.org/10.5021/ad.2011.23.4.455, Daejeon, Korea.