Hair drying is considered a simple step. However, it can impact hair health. Specific techniques and actions help care for hair during drying and prevent damage. Let’s explore them together.
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How to dry your hair without causing damage?
Summary
Published June 9, 2025,
updated on June 9, 2025,
by
Pauline, Chemical Engineer
—
5 min read
Is wet hair more fragile than dry hair?
Yes, wet hair is more prone to breakage than dry hair.
This fragility is explained by the hair fiber structure. As a reminder, it comprises several concentric layers. The outermost layer is the cuticle, acting as a protective shield. The intermediate layer, the cortex, consists of keratin, and the innermost layer is called the medulla. When hair is immersed in water, the scales that make up the cuticle lift and lose cohesion, which exposes the hair’s inner layers. Moreover, water penetrates the hair fiber and disrupts the hydrogen bonds linking keratin chains, making the structure more unstable.
Swollen with water, hair tends to elongate under its own weight, increasing its susceptibility to mechanical deformation. Running a brush vigorous brushing or harsh towel rubbing can cause permanent damage. Studies show dry hair can stretch up to 20% beyond its original length before breaking, while wet hair can stretch up to 50% before breaking. However, the force required to break the fiber—its tensile strength—is lower when hair is wet than when it is dry, which means wet hair is more likely to break under a lower force, despite its increased elasticity.
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Techniques for drying hair without causing damage.
To preserve the structure and health of your hair, it is important to be cautious when drying it because, as noted, wet hair is fragile.
Contrary to what one might think, air-drying hair is not the gentlest method.
Indeed, air drying keeps hair wet for an extended period—several dozen minutes or hours, depending on texture. This exposure lets water penetrate the cuticle and weaken hair fibers. A study showed that air drying tends to damage the hair’s cellular membrane complex. Composed of lipids and proteins, this complex is essential to cuticle cell cohesion. Its breakdown compromises the fiber’s seal and protection. It is preferable to dry your hair after showering, using a towel or a hair dryer.
Method No. 1: Dry hair with a towel.
The first instinct after a shower is often to wrap hair in a towel. While this removes moisture, technique matters. Vigorous rubbing with a standard cotton towel generates friction that damages the cuticle and increases breakage. A comparative study measured mechanical wear in hair based on drying method after shampooing: hair dried with a cotton towel retained 20% of its mechanical strength, compared with 45% for hair patted with a microfiber towel (80% polyester, 20% nylon). Slow movements, coupled with a soft towel, can help dry hair without damage.
Note : Scientists also tested the effect of a hair dryer on hair’s mechanical resistance. They measured it at 10% of its initial value, below the value after towel drying. The method of using the hair dryer was not specified. This is regrettable because, as explained below, this technique can dry hair without damage depending on the movements applied.
Hair fiber strength after shampooing and drying using different methods.
Source: MARTINS M. et al. Insights on the hair keratin structure under different drying conditions. Journal of Natural Fibers (2023).
Method 2: Dry hair with a blow dryer.
Using a hair dryer is often criticized because the device is accused of drying out hair. It is true that high temperatures, a short distance, and constant, focused heat cause visible damage to the hair surface. A Korean study evaluated the impact of different drying protocols on hair structure by subjecting hair strands to 30 drying cycles under five conditions. Results show that as temperature increases and distance decreases, surface damage becomes more pronounced. At 95 °C and a distance of five centimeters, the hair cuticle showed visible alterations, similar to hair left to dry in air. The study also showed that air drying or very high-temperature drying (95 °C) can change hair color, increasing lightness over successive cycles, probably due to progressive oxidation of hair pigments.
Surface cuticle damage measured by scanning electron microscopy after hair drying: (A) no treatment, (B) shampoo and air-dry (ambient temperature 20°C), (C) shampoo and blow-dry for 60 seconds at 15 cm (47°C), (E) shampoo and blow-dry for 15 seconds at 5 cm (95°C).
Source: LEE W.-S. et al. Hair shaft damage from heat and drying time of hair dryer. Annals of Dermatology (2011).
This study indicates the ideal method to dry hair without damage. Hold a hair dryer in constant motion 15 cm from the hair at a moderate temperature of 47 °C.
Sources
LEE W.-S. & al. Hair shaft damage from heat and drying time of hair dryer. Annals of Dermatology (2011).
HWANG S.-T. & al. Evaluation of changes and characteristics of hair according to the application of the hair dryer plasma functional module. Journal of the Korean Society of Cosmetology (2021).
WORTMANN G. & al. Comparing hair tensile testing in the wet and the dry state: Possibilities and limitations for detecting changes of hair properties due to chemical and physical treatments. International Journal of Cosmetic Science (2022).
MARTINS M. & al. Insights on the hair keratin structure under different drying conditions. Journal of Natural Fibers (2023).
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