Last updated on 12/28/21
Have you ever wondered what is flash drying and how it affects your hair?
As a curly head, you want to make sure that you’re taking care of your hair in the best way possible. This means understanding all of the different ways that you can take care of it and using the right methods for your specific type of hair.
One of the top issues I’ve come across in the curly hair community is flash drying and there are a lot of questions surrounding it. But, what exactly is flash drying? How does it affect your hair? And, most importantly, is it a good or bad thing? Let’s explore all of these questions and more!
In this article, I will give you the 411 on what it is and how to prevent it from happening.
What is Flash Drying?
Flash hair drying is a technical term that you’ve probably heard at least once within the curly hair community. But what exactly is it? It is defined as “an instant flush out of the water from hair” as a result of a product application or treatment.
If you’ve ever experienced this, it feels like most of the moisture has been drawn out of your hair. It could be a shocking experience where your wet hair, all of a sudden turns into brittle, rough, hard, and rigid hair, which then becomes difficult to manage and style.
Is it Good or Bad?
It’s all about perspective. Some like it and some don’t. In our opinion, it’s not good. No one wants frizzy, brittle, rough, hard hair, on top of spiky hairs spread randomly all over your head.
So, what is this? What is the cause? We need answers…
Causes of Flash Drying
Here’s a little science to help break things down. Hair is porous, bio-composite material that may absorb water, and its water uptake varies according to the surrounding humidity conditions.1
As hair absorbs water, it swells, and its diameter increases due to high water level inside. This is even more prominent under high humidity conditions when there is more water outside.
Water uptake by hair is a “Two Way Traffic” where hair absorbs or may desorb (lose) water depending upon the surrounding conditions. Damaged hair fibers are more susceptible to this and are known to suffer these water equilibrium changes more severely.
Certain chemical agents and ingredients can influence (or disturb) this two-way traffic of water molecules across the hair shaft (in and out). Humectants, e.g., glycerin, is one familiar example of such an ingredient and it’s abundantly used in hair care products.
Other moisturizing ingredients also have the ability to retain moisture content while their water uptake capacity varies depending upon their molecular structure and chemistry.
Aloe vera and polymeric ingredients are also known for the same reasons. How could these ingredients cause flash drying? There could be various possible mechanisms involved.
Humectant Mechanism: Water Outflow
Humectants are chemical molecules that can absorb water. Some examples are glycerin, propylene glycol, urea, sorbitol, and other polyhydric alcohols. Starch-based molecules, e.g., glucose and lactose, can also absorb moisture.
Humectants are excellent moisturizing agents and are added to a formulation to keep hair hydrated. However, if they are used in large amounts or under low humidity conditions (dry weather), they may act in a slightly different way. They can absorb water molecules from the hair cortex and flush them out, resulting in less water content for hair.
In simple terms, glycerin will absorb water molecules from wherever it will find it easily and in excess. When there are more water molecules in the atmosphere, glycerin will absorb them and transport them to the hair, resulting in increased hydration.
However, if more water is available in the hair (and the air is dry with low humidity), it will flush water out of the hair, and cause the hair to become dry — this follows the thermodynamic equilibrium.
“Flash drying” is potentially due to the excessive available water and its uptake by humectants. There is a lot of water, and applying a humectant will cause the water equilibrium to shift in favor of the surrounding, resulting in water loss
Surface Coating Mechanism
Film-forming ingredients are used in hair care formulations to produce a fine film on the hair’s surface to protect hair from external changes such as humidity.
Hairstyling products like gels, curling custard, or creams contain these polymeric film formers. In addition to their function of improving the appearance and volume of hair, their film can sometimes make hair stiff and hard — this may happen suddenly, even if your hair is wet.
Thus, the tough coating is an obstacle to any further penetration of active ingredients and water molecules.
Hard Water: Deposits of Calcium and Magnesium
Water is a universal solvent, and it is the most common cleaning solution. It can be soft or hard, depending upon the concentration level of calcium and magnesium ions.
Tap water transports these metal ions to your hair. Repeated metal ion deposits on the outside cuticular surface of the hair fiber may lead to a crystalline formation on the hair shaft.
Recent studies have demonstrated that metal build-up alters the physicochemical and cosmetic features of hairs (combing force, sensory feel, and shine).2-3 This significant build-up of metal may hinder the penetration of active ingredients leading to unwanted and undesired results, and flash drying is one of those results.
Ingredients That May Cause Flash Drying
With the above discussion, we can make a list of chemicals and ingredients that we should possibly avoid preventing any flash drying.
Glycerin. Our old friend glycerin has been around for so many years. The products containing high amounts of glycerin (5.0 – 10.0%) may cause severe flash drying.
Though it is a cost-effective humectant/moisturizer for skin and hair care products, it works in two-way traffic, and under wet hair conditions, may cause flash drying. Glycerin is the most mentioned ingredient responsible for flash drying.
Aloe Vera. Aloe vera is a fantastic ingredient for its wide range of benefits. It contains more than 300-400 different chemicals that work together to provide dermo-cosmetics performance.
The main components are various polysaccharides (Starch), glycosides, such as mannan (Mannose sugar), and its acylate derivative acemannan.4 It also contains a protein molecule made up of essential amino acids.
Haircare products with aloe vera ingredients are also prone to causing flash drying. The possible reason is the synergistic effect of starch molecules and proteins. These molecules are capable of withholding and attracting large amounts of water from the hair, inducing a sudden water loss.
Film-forming Polymers. Conditioning polymers are a common element of haircare products. Most of them are large, high molecular weight molecules forming a thin coating on the hair shaft.
PVP and its derivatives are primary examples of such polymers offering good moisture resistance and styling under extreme humidity conditions. However, build-up and stiffness can occur as a result of overuse and repeated applications.
The water repellent layer changes the surface properties of hair, and the subsequent application of cleansing and conditioning products responds differently. The hair-water balance is altered, and the hair appears dry, giving a tactile sensation of “Flash Drying.”
How to Prevent Flash Drying
• Regularly use a deep cleansing shampoo, having moderately acidic pH to remove/minimize product build-up.
• Avoid harsh sulfate shampoos, as they increase hair protein loss and can damage the hair, which subsequently alters hair-moisture equilibrium and induce flash drying.
• If your hair is sensitive to proteins, it’s best to avoid products having large protein molecules.
• Use soft water for everyday cleansing; the metal build-up is detrimental to your hair health. Acidic pH shampoo (or chelating shampoo) will help the removal of calcium and magnesium ions.
• Don’t use heavy high molecular weight oils/butter and waxes such as beeswax, petrolatum, carnauba wax.
In case you have flash drying right after using a particular product, and you need a quick solution:
- First, try adding more water.
- Immediately wash your hair using a deep cleansing shampoo to remove product residue.
- Apply a regular conditioner to detangle your hair and rinse it off.
- Apply a low polymeric leave-in conditioner. Pay attention to ingredient listing; the product should not have polymeric styling ingredients.
Flash drying is a surprise and shocking experience, and any one of us can experience this. It is difficult and challenging to pinpoint exactly when and what caused the issue, as every one of us has different textures.
The primary components that might induce flash drying are high molecular weight starch-based molecules, humectants, and film-forming polymers. So make sure to check the ingredients in your products.
The workaround for flash drying, which can make your hair hard, brittle, and frizzy, is to avoid these ingredients and attempt to remove the culprits.
The good news is that you now know what to do, should this situation occur again.
As always, remember to let your hair be your guide!
Let us know in the comments below if this article was helpful!
1. Zviak, C., The Science of Hair Care. Taylor & Francis: 2005.
2. Godfrey, S.; Staite, W.; Bowtell, P.; Marsh, J., Metals in female scalp hair globally and its impact on perceived hair health. Inter. J. of Cosmet. Sci 2013, 35 (3), 264-271.
3. Evans, A. O.; Marsh, J. M.; Wickett, R. R., The structural implications of water hardness metal uptake by human hair. Inter. J. of Cosmet. Sci 2011, 477-482.
4. Burlando, B.; Verotta, L.; Cornara, L.; Bottini-Massa, E., Herbal Principles in Cosmetics: Properties and Mechanisms of Action. CRC Press: 2010.