How often should you wash your hair?
There's no one right number, but there is a good place to start. If your hair is curly, washing every few days to once a week works for many people. If your hair is tightly coiled (type 4), start with once a week or every other week. And whatever your hair type, it's time to wash when your scalp feels greasy, itchy, dirty, or coated with product.
However, the American Academy of Dermatology advises that people with straight hair and an oily scalp may want to shampoo daily. But people with dry or textured hair, such as wavy hair, curly hair, or kinky hair, may be able to go longer between washes.
Straight hair requires more frequent washing and tends to look more oily, as sebum easily and quickly coats straighter hair strands.
Wavy, curly, and kinky hair types tend to stay a bit drier than straight hair, as it's more difficult for oils to travel down curlier hair types.
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Dermatology reviews describe how sebum (i.e., your scalp's natural oil) has trouble spreading evenly down wavy, curly, and coily strands. That can leave your scalp oily while the rest of your hair feels dry, so let your scalp help decide when it's time to wash.
Note that washing more often than your hair needs means more detangling and handling, which can increase your chances of breakage. Seeing more hair in the drain on wash day doesn't necessarily mean you have hair loss, though. It's normal to shed 50 to 100 hairs a day, and wash day can release hairs that have already shed.
This is especially true if you're using harsh shampoos or if you consistently wear hairstyles that pull at the roots of your hair or stress your edges.
How Often Should You Wash Your Hair?
We recommend washing your hair no more than every other day and as little as once per week for curly hair. Washing curly hair too often could be very drying, depending on the ingredients in the shampoo.
Co-washing your hair or using the Curly Girl Method are options to consider if you want to try a washing routine specifically designed for curly girls.
For people with a kinky hair type (often referred to as type 4), we recommend washing your hair once a week or every other week. Note that the American Academy of Dermatology provides a similar recommendation.
For people with straight hair, washing your hair every two to three days is generally acceptable.
If you've had chemical treatments like perms or relaxers, wash gently rather than rarely. Once a week or every other week still works, and the American Academy of Dermatology advises washing textured hair at least every two to three weeks. Condition every time, because chemically treated hair dries out and breaks more easily.
Ultimately, there is no blanket recommendation, and paying attention to your hair's needs is important to determine how often you should wash it. How often you should wash your hair depends on several factors, such as hair type, lifestyle, and scalp condition.
Where to start, by hair type
We recommend starting with the schedule for your hair type. Then adjust one wash at a time, based on how your scalp and hair feel.
| Start with | Your hair | What to know |
|---|---|---|
| Every day may work | Straight hair with an oily scalp | The American Academy of Dermatology says you may want to shampoo every day if your hair is straight and your scalp is oily. |
| Every 2 to 3 days | Straight hair that doesn’t get oily fast | Oil moves down straight hair easily, so it can look greasy sooner than curly hair. |
| Every few days | Wavy hair | Wavy and curly hair can have an oily scalp and dry ends at the same time. Wash for your scalp, and condition your ends. |
| Every few days to once a week | Curly hair | Washing more than every other day is rarely necessary. Let your scalp decide where you land in that range. |
| Once a week or every other week | Tightly coiled hair (type 4) | The American Academy of Dermatology gives similar advice. It says this helps prevent product buildup, which can dry out your hair. |
| At least every 2 to 3 weeks | Any dry, textured, curly, or thick hair | This is the longest gap the academy suggests. Wash sooner whenever your scalp needs it. |
| As often as your hair type needs | Braids, weaves, and other protective styles | Keep your scalp clean while you wear braids or a weave. The academy also recommends wearing braids for no longer than 6 to 8 weeks. |
| Dandruff shampoo about once a week | Curly or coily hair with dandruff | Wash when your hair needs it, and use the dandruff shampoo about once a week. Put it only on your scalp, because it can dry out your hair. |
These are starting points, not rules. If your scalp feels greasy, itchy, dirty, or coated with product, wash it, even if it hasn’t been a week.
Signs It's Time to Wash Your Hair
Your scalp will usually tell you when it's time to wash. The American Academy of Dermatology puts it simply: wash your hair based on how often it gets dirty or oily. Here's what we look for.
- Greasy. Your roots look shiny or flat, or your scalp feels slick when you touch it. That's natural oil from your scalp building up near the roots.
- Itchy. Your scalp itches between wash days. Oil, sweat, and dead skin collect on your scalp, just like they do on the rest of your skin.
- Dirty. You can see lint or dust on your scalp or along your part.
- Coated with product. Your curls feel heavy, waxy, or weighed down, or your products stop working the way they used to. That's usually buildup from gels, creams, and oils.
- It smells. Your scalp has an odor, even after you refresh your curls.
If you notice any of these, it's time to wash, even if it hasn't been a week. But if your scalp feels fine and only your hair feels dry, you may be able to wait and refresh your curls instead.
Flakes need a closer look. The academy notes that flakes can come from not shampooing often enough, or from not using the right conditioner, oil, or scalp moisturizer for your hair type. Dandruff itself isn't caused by poor hygiene, but the NHS notes that it may be more obvious if you don't wash your hair regularly. If your scalp is painful or inflamed, or the flakes don't improve after four weeks of using an anti-dandruff shampoo as directed, see a doctor or dermatologist.
Does Washing Less Train Your Scalp to Make Less Oil?
No. Your scalp makes the same amount of oil whether you wash once a week or three times a week. In a 1979 study, researchers changed how often people shampooed, from once a week to three times a week. It made no real difference in how quickly the oil came back to their hair.
The researchers also found no sign that washing tells your oil glands to make more oil. So we don't recommend trying to "train" your hair by stretching out wash days. Wash on the schedule your scalp and curls actually need.
What Happens If You Go Too Long Between Washes?
If you've ever stretched wash day out to two or three weeks, you may have noticed that your scalp starts to itch before your curls look like they need a wash. Your scalp is skin. It sheds dead cells, makes oil, and collects sweat and product, so it needs a regular wash even when your curls would be happy to wait.
The American Academy of Dermatology says washing once a week or every other week helps prevent product buildup, which can dry out your hair.
The most extreme example comes from a Japanese research team who spent three months in Antarctica without being able to bathe or shower. In this small study of 16 team members, the amount of a yeast called Malassezia living on their scalps increased by roughly 100 to more than 900 times, and the team members developed itchy, scaly scalps. This was an extreme environment, so it doesn't tell us how often women with curly hair should wash. It does show that going without regular cleansing can change the scalp environment.
A large study of 1,500 adults in China also found that people who washed more often had less flaking and itching. However, that study had important limits. A shampoo company paid for it, the people in it had straight or slightly wavy hair, and in the part of the study where people washed every day, they used a dandruff shampoo. The authors said they don't know whether the results apply to curlier hair.
Going longer between washes may work well for your curls. But if your scalp becomes itchy, oily, flaky, or coated with product, your current gap between washes may be too long.
How to Wash Your Hair Without Drying Out Your Curls
We recommend shampooing your scalp instead of your whole head and using conditioner every time.
Put your shampoo on your scalp and massage it in gently. When you rinse, let the suds run down through your curls instead of rubbing shampoo into your hair strands. The American Academy of Dermatology recommends this because it washes away product, dead skin, and extra oil without drying out the hair too much.
Use conditioner every time you wash. The academy recommends applying it to the full length of dry or curly hair. Pay extra attention to your ends, since they're the oldest and most fragile part of your hair.
Then detangle while the conditioner is still in. Hair is delicate when it's wet, so the academy suggests a wide-tooth comb instead of a brush. If your hair is thick and curly, it says the best time to comb is in the shower, before you rinse out your conditioner. A dermatology review also notes that combing highly coiled hair takes less work when it's wet than when it's dry.
Every extra wash day is one more detangling session, and each session is another chance for breakage if you aren't gentle. Work in sections and take your time each wash day.
Workouts, Swimming, and Protective Styles
If you work out and sweat a lot, you don't always need a full shampoo. Rinsing and conditioning your hair after a heavy sweat can be enough between shampoos. That's what the American Academy of Dermatology suggests for children with dry, curly hair after heavy sweating or swimming.
If you swim, rinse your hair as soon as you get out of the pool. The academy recommends this for swimmers.
If you wear braids, a weave, or another protective style, keep your scalp clean and wash your hair as often as your hair type needs. The academy also recommends wearing braids for no longer than 6 to 8 weeks.
Should You No-Poo or Shampoo Your Hair?
Some women in the natural hair community use a co-washing technique to clean their hair. This concept of co-washing, also known as conditioner washing, involves washing your hair using a conditioner instead of a traditional detergent-based shampoo.
When I mention a traditional detergent-based shampoo, I am talking about commercial shampoos, which include sodium lauryl sulfate (SLS), SLS-free brands, shampoo bars, castile soap, and other types of soap.
Does Co-Washing Really Work?
Shampoos are usually used to remove dirt and oil from your hair. This dirt can be in the form of particles, lint, dust, and other substances which stick to the oils coating your hair strands.
However, a common complaint with shampoo is that it can make your hair feel dry. This is the primary reason why many naturals prefer to co-wash their hair. In theory, co-washing would never completely strip the hair of all of its natural oils, leading to less overall dryness.
Some women have even decided to wash their hair using only water. So, does water washing or conditioner washing adequately clean your hair and scalp?
Water Washing
Based on our research, water washing your hair tends to only spread the hair's natural oil more evenly over your hair strands. However, water washing does not clean your hair or remove excess oils, meaning that the hair will still be dirty and unwashed.
Co-washing (Conditioner Washing)
Conditioner washing (co-washing) can surprisingly provide a decent level of cleanliness to your hair. This is because co-washing products can remove some of the oil coating of unwashed hair.
Co-washing removes some of the oil from your hair, but conditioner can't clean as thoroughly as shampoo. So does co-washing effectively clean your scalp?
In short, I don't think co-washing is effective at cleaning your scalp over a long period of time due to leftover oils and conditioner build-up. Note that this is my opinion, as I haven't found any studies that prove or disprove this theory.
A dermatology review published in 2018 came to the same conclusion. Conditioner is made to add things to your hair, not to remove dirt and buildup, so co-washing shouldn't replace shampoo completely.
So, if co-washing works well for your hair, we recommend continuing to use the hair care routine that works best for your hair.
Traditional Shampooing
Using commercial shampoos is the best way to clean your hair as it completely removes visible scalp oils and deposits on your hair. Although, the problem is that these shampoos can completely strip your hair of moisture leading to the feeling of dry hair, especially with frequent washing.
If you decide to exclusively co-wash your hair, the buildup of conditioner deposits on your hair can happen, and an occasional shampoo is important, even if you are committed to a co-washing regimen.
Shampooing is still the best way to clean your hair. Co-washing is an acceptable alternative, but periodic shampooing (or frequent shampooing, depending on your needs) is still recommended.
We don't recommend water washing due to the lack of effectiveness. We also don't recommend using dry shampoo unless you don't have another option at the moment.
We consider dry shampoos "temporary" solutions to be used in a pinch. For example, you're on vacation with an oily scalp and can't use your normal washing routine.
How Does Shampoo Work?
Are you familiar with the saying that oil and water don't mix?
This saying is more important than ever when it comes to understanding how shampoos work. Oil will always separate and float on top of the water.
Even if you are able to vigorously mix the oil and water, you will, at best, get droplets of oil within the water. Plus, if you allow the mixture to settle, the oil and water will once again separate.
Now, you may have noticed dish detergent is able to remove oils from dirty dishes. The reason is due to the dish detergent containing surfactants.
Surfactants are special chemicals that have (1) a polar head and (2) a lipid tail. The polar head loves water, and the lipid tail loves oil. Some surfactants, like sodium lauryl sulfate (SLS), are able to interact with both oil and water.
With surfactants like SLS, chemists can combine water and oil without them separating. This allows the oil to completely dissolve in water. This process occurs because the surfactants create micelles, a mixture of oil, water, and a surfactant.
Now that we understand micelles, let's discuss SLS.
In the natural hair community, SLS has a reputation for drying out your hair. It's often completely avoided by many women. However, there is a reason why it's often used in commercial shampoos. SLS is a fantastic surfactant.
Let's compare two scenarios to illustrate the purpose of SLS:
- If you decide to use a water washing regimen, washing your hair with only plain water, this process will dislodge some oil, but your hair will still be dirty.
- If you decide to use a shampoo with a surfactant (like SLS), the oil will be removed from your hair. This is because the surfactant will cause the water and oil to form micelles that are going to carry the oil away when the shampoo is rinsed out of your hair.
It's important to note that some women don't want squeaky clean hair; remember, that's one of the main reasons why so many women use co-washing instead of shampooing their hair daily.
Although, if you're trying to remove a silicone-based product and have excess conditioner or oil build-up on your hair and scalp, then you may find yourself using an SLS shampoo to give you fresh, clean hair.
...But, Are Sulfate-Free Shampoos Better for Your Hair and Scalp?
While there are no official classification parameters for sulfate-free shampoos, cosmetic companies usually classify their shampoos as sulfate-free when they don't contain ammonium lauryl sulfate (ALS), sodium lauryl sulfate (SLS), ammonium lauryl ether sulfate (ALES), and sodium lauryl ether sulfate (SLES).
Are Sulfate-Free Shampoos Gentle?
Several sulfate-free shampoos are gentle and aren't irritating to your hair, scalp, and skin. However, this is not always the case.
As such, you should always trust the way your hair and scalp feel after using a sulfate-free shampoo. It is important to note that many sulfate-free shampoos use an ingredient called olefin sulfonate.
Olefin sulfonate is often used in the place of SLS, which is a very effective surfactant that gets rid of oil very quickly.
Likewise, olefin sulfonate is pretty effective at removing hair oils, and it can still be drying or irritating for some scalps. Sulfate-free doesn't automatically mean gentle, so the way your scalp feels after a few washes tells you more than the label does.
Olefin sulfonate is usually classified as a mild surfactant, though that classification won't tell you how your own scalp reacts.
However, not all sulfate and sulfate-free shampoo surfactants are harsh. Some are gentler than the sulfates. For example, sulfate-free sorbitol esters are much gentler.
What's the Difference Between Sodium Lauryl Sulfate (SLS) and Sodium Laureth Sulfate (SLES)?
These ingredients are effectively the same, although one is gentler than the other. The phrase 'eth' (i.e., laureth) is a reference to ethoxylation, a process by which the SLS is converted to SLES.
SLES starts from the same fatty alcohol as SLS, but it goes through an extra step called ethoxylation before it becomes a sulfate. That makes it a milder detergent. Dermatology reviews describe laureth sulfates as mild cleansers that still foam well, and they're often used in shampoos for normal to dry hair.
Using Natural Shampoo Alternatives
Bentonite Clay Wash
We don't typically recommend bentonite clay, but we've been pleasantly surprised with the effectiveness of the clay wash.
The cleanliness level provided by bentonite clay, which turns into a silky paste, seems to be similar to a co-wash. Most of the oil layer is removed, with only a few remnants of surface oil remaining.
Rhassoul Clay Wash
Rhassoul clay wash does not create a silky paste-like bentonite clay, but it appears to clean in a very similar way. The cleanliness of the hair appears to be similar to a typical co-washing session, where most of the surface-level oil has been removed.
Apple Cider Vinegar
Some naturals promote apple cider vinegar as a natural cleanser. We don't usually recommend using apple cider vinegar (ACV) as a standalone cleanser, but we do like some commercial shampoos that use ACV as a primary ingredient.
In our experience, ACV alone will only provide marginal cleanliness compared to co-washing or SLS-based shampoos.
Shikakai Shampoo
Shikakai shampoo is often recommended as an Ayurvedic shampoo for those with an affinity for natural products.
We only periodically mention Ayurvedic hair treatments, but my friend Phoenyx Austin tends to talk about these treatments more frequently.
Shikakai shampoo is produced using crushed acacia pods that contain saponins. The root of the Saponaria plant is commonly used in commercial soaps and shampoos.
In our experience, shikakai shampoo provides marginal results compared to co-washing or traditional commercial shampoos.
If you're interested in learning more about Ayurvedic hair care, we recommend reading Phoenyx's book, 'If You Love It, It Will Grow'.
Homemade Soaps, Natural Soaps, and Shampoo Bars
Traditional soaps, for example, if we make an olive oil soap with sodium hydroxide, produce pretty clean hair. However, homemade soaps are often not considered mild cleansers, and we recommend being cautious with hair products that have high pH levels.
Conceptually, we provide the same advice for users of castile soap and African black soap. If you use undiluted or less diluted castile soap you're likely to completely remove the oil layer.
So, depending on the formulation, homemade soaps, natural soaps, and shampoo bars can be very similar to traditional SLS-based commercial shampoos.
Baking Soda
Baking soda continues to be a pretty popular natural cleanser in the natural hair community, but in our experience, baking soda doesn't seem to clean the hair very well. The hair will often remain oily after multiple uses of baking soda.
Basic Shampoo Ingredient Formulations and Primary Functions for Washing Your Curly Hair Type
This section includes the most common formulations and ingredients in commercial shampoos (source).
Detergents
Detergents are designed to remove dirt from the hair and scalp. They also remove sebum, styling products, and skin scales.
Several detergents are included in cleansing products, but the most common ones are sodium laureth sulfate, sodium lauryl sulfate, sodium olefin sulfonate, ammonium lauryl sulfate, ammonium laureth sulfate, TEA-lauryl sulfate, and DEA-lauryl sulfate.
Foaming Agents
These foaming agents are included to cause commercial shampoos to form suds. Many people believe that foaming equates to cleanliness. However, this simply isn't true. Foaming and cleaning are completely unrelated.
Conditioners
Conditioners are what leave your hair feeling soft and smooth after the detergent has removed the dirt and oil from your hair and scalp.
Thickeners
Thickeners are responsible for increasing the thickness of a shampoo formulation. One common misconception is that thick shampoo is superior to thin shampoo. The thickness of the formulation doesn't affect the shampoo's performance.
Opacifiers
Opacifiers are used to make a shampoo opaque or a whitish, milky color. It is solely for aesthetic purposes and has no impact on the shampoo's performance on your hair.
Sequestering Agents
These agents prevent soap scum from forming on the scalp and within the hair while washing your hair with hard water. Sequestering agents are one of the primary differences between a bar cleanser and a liquid shampoo.
Fragrances
Scents (or fragrances) are added to make a shampoo smell good. If a fragrance wasn't used in shampoo, then it likely wouldn't smell good to consumers.
Preservatives
The last thing a consumer wants is for their shampoo to become contaminated. This is why preservatives are used in commercial shampoos. More specifically, preservatives are used to prevent fungal and microbial contamination of the shampoo.
Special Additives
These special additives are commonly referred to as treatment ingredients.
These additives, for example, include jojoba oil or amla oil, are also used as marketing aids to other benefits of the shampoo being sold, and are used as additions to the cleansing effects of the shampoo.
As for what kind of additives are used, this varies from one brand of shampoo to the next.
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With straight, wavy, curly, and kinky hair types, plus everything in-between, everyone's hair is a little different. So, generally speaking, there is no way to provide an exact answer, but we do encourage women to wash their hair regularly to mitigate product buildup and encourage hair health.
How often you should wash your hair depends on your hair regimen, workout regimen, outdoor activities, the climate in your geographic regimen, scalp health, and much more.
For newbies, I recommend that you start out washing your hair once per week with lukewarm water. Determine how your hair feels, record it in your natural hair journal, and increase or decrease your washing frequency as needed.
If you're not sure which way to adjust, try adapting a simple method the American Academy of Dermatology gives parents. If your hair or scalp looks oily, add one wash a week. If your hair feels dry or dull, remove one wash a week. See how your hair and scalp respond before changing the schedule again.
Even after you settle on a wash routine, you will need to make adjustments as the needs of your hair may change based on your lifestyle changes.
