The frequency at which you should shampoo your hair is a mysterious and mercurial science. I’ve heard advice ranging from “wash in the morning and at night,” to, “wash once a month and use hair oil the other 29 days.” So what are some things that happen when you wash your hair too much, or too little? As someone with curly, fine hair, there seems to be some kind of delicate balance of shampooing I’m supposed to maintain, and if I get it wrong, my hair can easily get too dry or too greasy (there’s got to be a Goldilocks middle ground here). My scalp is sensitive too: it gets itchy, red, flaky, and oily if I’m not careful. I talked to Dr. Jeff Donovan, a Canadian dermatologist who specializes in hair loss and health, and it turns out the answer is more nuanced than I thought.
Dr. Donovan stresses the importance of tailoring your habits to your specific hair type, saying, “This is not a simple question because what constitutes 'too often' is different for everyone!” So what are the different hair types? It doesn’t boil down just to “straight” or “curly.” There’s a wide range of hair types, from the follicle to the thickness and texture of each strand. I looked on the Curl Centric website, which provided a thorough though perhaps not conclusive list of hair types. First of all, note the thickness of your individual strands: How can you tell the difference between fine, medium, or coarse hair? You can test it by feeling an individual strand to check it for thickness. Then note the general texture of your hair (such as straight, wavy, curly, and natural). Hair types are more of a spectrum than a set of distinct categories, so you may find you fall in between hair textures or strand types, and you may have a mixture of different types.
1. Shampoo Too Much: Stripping Your Scalp’s Sebum And Scalp Microbiome
An important factor to consider when deciding your shampoo schedule is your scalp. Do you find it tends to be oily, or dry? Do you get irritation, flakiness, redness, or dandruff? Your scalp health is not only important for your physical comfort, but for your hair health. As explained on the Head & Shoulders website, scalp oils (sebum) coat and protect your hair, so even though excessive oils can make your hair look greasy, too little oil will dry out your hair. There’s also evidence that your scalp hosts a microbiome that impacts your scalp & hair health, including protecting it from infection, as Happi magazine reported. Understanding your hair and scalp types will help allow you to craft a personalized formula for hair maintenance.
2. Shampoo Too Little: Hair Greasiness
Once you’ve got a handle on your unique hair and scalp combo, what’s the best shampooing ritual for you?
"A woman with curly hair might be said to be shampooing 'too often' if she shampoos daily. But daily shampooing might be absolutely perfect for a woman with fine hair especially if she has hair thinning issues or has excessive oiliness,” says Dr. Donovan. “I often advise my patients with fine hair to shampoo their hair every day or every second day. Without doing this the normal oils often just weighs down the hair making it look greasy.” With curly hair, you have more time for the oils to saturate your hair: “Women with curly hair shampoo less often as it takes longer for the normal oils to work their way down the hair shaft,” Dr. Donovan advises.
3. Shampoo Too Little: Seborrheic Dermatitis
Speaking from personal experience, even with curly hair I can’t go more than two days without washing before my hair gets uncomfortably greasy, due to how fine it is. My scalp also requires more frequent attention. “Women with seborrheic dermatitis often shampoo more often otherwise the oiliness and excessive itching is too troublesome. Seborrheic dermatitis is an inflammatory scalp condition that closely relates to dandruff,” says Dr. Donovan. Personally, I typically wash my hair every day, especially if I go to the gym, with a gentle, sulfate-free shampoo, or a medicated shampoo to treat seborrheic dermatitis. I also use a hair mask or conditioner to help moisturize the hair after shampooing.
4. Shampoo Too Much: Damage And Loss Of Luster
Balancing scalp health with hair dryness can be an intricate equation, especially for women with natural and fine hair that can become frizzy, damaged, or dry with too much shampooing.
“Women who shampoo too often may develop excessive dryness and brittleness. The hair breaks easily and loses its shine,” Dr. Donovan tells Romper.
5. Shampoo Too Little: Alopecia & Folliculitis
Conversely, too little shampooing can cause scalp folliculitis (infection of the follicles), or alopecia (patchy hair loss), especially for those with natural hair, as Dr. Lily Talakoub wrote for MD Edge Dermatology. She suggested finding your own personal shampoo hair groove, testing out products and methods such as sulfate-free shampoo, lather only on the scalp (leaving the ends alone), shampooing just a couple times a week, or using dry shampoo between washings to promote scalp health while preventing hair dryness.
Dr. Donovan insists you should go with the (hair) flow: “There are some helpful basic suggestions about shampoo frequency but they are by no means rules. Many people come to know what it takes to give them great looking hair and a scalp that feels great too.” So when you discover the hair washing frequency that seems to make your hair and scalp happy, listen to what your head is telling you.