What’s the longest you’ve gone without washing your hair? Mine was (gulp) seven whole days. I had just dyed my hair silver and avoided cleaning to preserve the color longer. My scalp was itchy. My hair looked greasy. I felt gross. Yet I kept styling it and sweating during workouts, then dousing my head in a cloud of Klorane. I’m not alone—not washing your hair has become a punchline and badge of honor, of sorts, in the same way proclaiming you’re “soooo busy” has But, is relying too much on dry shampoo bad for your health?
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I turned to Dr. Dominic Burg, chief scientist and hair biologist for évolis Professional. An expert in trichology (that’s the scientific study of hair and scalp health), he answered all my nitty gritty questions about overusing dry shampoo. PSA: There is such a thing as too much dry shampoo, and what happens when you reach that point isn’t pretty.
I am always saying my hair is “dirty.” It’s a feeling. But what is that dirt, exactly?
Each hair follicle has a small oil gland attached to it. These are known as the sebaceous glands. The sebaceous glands produce a material called sebum, which provides lubrication and moisture to the hair and are also important for providing the natural oils for the skin. Some people produce more of these oils than others. “Dirty” hair is a combination of build-up of the natural scalp oils and sweat residue on the hair shaft, which dust and pollutants stick to. For those of us that handle our hair a lot, dirty hair can also be a result of the transfer of our skin oils and other residues from the hands to the hair. Dirty hair can also be a little smelly. This is the result of your natural bacteria breaking down the oils and sebum on the hair.
Is there a limit to how much dry shampoo my hair/scalp could take?
Yes, definitely. Dry shampoo is not really meant for the scalp, but rather is meant to absorb excess oil from the hair strands. Many also provide a volume and texture boost. The fine starch powders used in dry shampoo can be very clogging for the pores of the scalp, particularly follicular pores, so any excess application to the scalp should be avoided if possible. Instead, focus on the hair strand’s lengths and ends. Excess powder on the hair strands should be brushed out thoroughly on a daily basis to avoid build up.
Why is layering too much dry shampoo bad for me?
You can think of it in a similar fashion to applying a foundation or powder to your face. You wouldn’t leave those products on your face for days on end. Your scalp is no different. The fine powders in dry shampoo can clog pores and prevent the scalp from breathing. This can lead to issues with scalp and hair follicle health. Dry shampoos with silicone can also coat hair fibers, preventing moisture from entering, resulting in drying and brittleness in the long term.
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Can using too much dry shampoo cause dandruff?
The fine starch and/or clay powders used in dry shampoo can be very clogging for the pores of the scalp, particularly follicular pores. Excess application of dry shampoo to the scalp will result in reduced ability for the scalp to breathe. This can result in itchiness and irritation. Excess dry shampoo on the scalp, and the resulting change in the amount of air that can reach the skin, may also lead to a microbiome change, or the change in the mix of good bacteria on your scalp, which can lead to scalp irritation and an increase in the bad bacteria and fungi that can causes dandruff. The natural starches in dry shampoo can actually act as food sources for the bad bacteria and fungi, exacerbating the problem.
Say I’ve been sweating from working out multiple days in a row, is it terrible if I don’t fully wash my hair and just use dry shampoo?
Dry shampoos are great for absorbing excess oils, sweat residue, and dirt from the hair. Traditionally, these should be applied to the hair fibers, left to absorb, and then brushed out rather than left in. If used in this manner—if the powder is combed out and not just sprayed on the hair and left for days—and if application to the scalp is avoided, it is perfectly fine to use a dry shampoo whenever necessary.
How often should I REALLY be washing your hair with water for optimum scalp health?
This will depend on your hair and scalp type. I recommend gently cleansing one to three times a week, using a sulfate and silicone-free cleanser, preferably with natural ingredients and added vitamins. If you are a dry shampoo addict, try to wash it out with water at least every second day.