Humans evolved without the need for shampoo so, for our hair, this daily cleansing ritual of shampooing can actually end up doing more harm than good.

The hair and scalp produces its own protective oils to protect the hair from drying out and splitting. These oils also protect the scalp from drying and other skin conditions.

Dandruff is more common today than ever before and that’s in part due to the overuse of shampoos. The main reason, though, for the prevalence of dandruff is poor diet, which will be discussed later.

By shampooing too much we strip away our protective oils and leave the hair and scalp vulnerable. However, most people need to shampoo regularly because their body is excreting toxins which have built up from poor diet, through the scalp.

Shampooing too much also shuts down the self-cleaning mechanism of your scalp. As the protective oils are stripped away, the skin produces more and more to replace them.

In this article, you’ll learn how often you should shampoo, and why using ‘off-the-shelf’ brand shampoos can end up damaging your hair in a significant way.

Then, we’ll discuss the best natural shampoos, the best natural ingredients for shampoos and how and why they are useful for overall hair health and stopping hair loss.

You’ll also learn about the chemicals found in most shampoos and why the manufacturers use them.

Hint: It’s because they smell, feel and foam nicely, but don’t offer much in terms of the general health of your hair.

NOTE: ‘Natural’ is an ambiguous word that’s used by many to mean different things. Throughout this piece, ‘natural’ refers to any plant or food products that have not been processed or synthesized in a laboratory. These can include seeds, leaves, stems, oils, and extracts.

The Evolution of Store-Bought Shampoo

For thousands of years, humans have used natural ingredients – plants, berries, and oils – to cleanse and beautify themselves (1).

In fact, cleanliness is imperative to the survival of humans, as it helps to slow the spread of diseases.

But cleanliness as we practice it today is nowhere near the way it was practiced by our earliest ancestors. It was a necessity, sure. However, it wasn’t an obsession or a daily occurrence.

For example, it wasn’t until the invention of liquid shampoo – created in 1927 by German Hans Schwarzkopf – that shampoo really began to take off in Europe and around the world (2).

It was then that shampoo became a necessity – the only proper way to maintain one’s scalp hygiene.

Is Shampoo Necessary?

Cosmetics manufacturers will have you believe that shampoos and conditioners are a necessity.

But the truth is, the scalp already provides its own natural cleansing process that removes the need for shampoo entirely.

The Scalp’s Natural Cleansing Process

The scalp is a complex environment, and one that has adapted to care for itself. This means that many of the cleansers we use on a regular basis aren’t really necessary, and they can even cause harm.

Sebum is a natural lipid produced by the skin’s sebaceous glands and it “consists of squalene, esters of glycerol, wax and cholesterol, as well as free cholesterol and fatty acids. (3)”

These lipids work together to protect the skin and hair of the scalp.

In fact, sebum has been shown to protect against damage caused by sunlight, as well as free radicals and microbes, including bacteria and fungi (4).

And sebum has even been shown to contribute to “the pro- and anti-inflammatory skin properties” that are necessary for maintaining a proper balance and protecting against injury and illness (4).

When the scalp is healthy – free of disease, uninjured, and otherwise functioning as it should – the sebum levels produced are enough to protect the scalp without causing oiliness or discomfort.

However, a variety of health conditions and lifestyle factors can contribute to sebum overproduction.

This then triggers the ‘need’ for shampoos, which only perpetuates the cycle of cleansing.

Off-the-Shelf Shampoos: The Truth

While many brands are moving towards more natural, organically-sourced ingredients, there are still a few major categories that they won’t remove from their formulations – namely, preservatives, surfactants, and detergents.

Preservatives ensure a longer shelf life, while surfactants and detergents provide a more consistent and ‘shelf-worthy’ end product. However, they can all cause significant damage to the scalp’s natural cleansing process (5).

Let’s take a closer look at some of these ingredients and why you should avoid them.

The Ingredients

While this list isn’t exhaustive, it does provide a look at some of the most common – and most harmful – ingredients found within shampoo.

Sodium Lauryl Sulfate (SLS)

When applied topically, SLS has been shown to strip the natural oils from the skin and cause irritation and sensitivity (6). In those that are also hypersensitive, this can further complicate the issue (7).

Study: Susceptibility of atopic dermatitis patients to irritant dermatitis caused by sodium lauryl sulphate (1991)

Atopic Dermatitis (AD) is a skin condition characterized by a red, itchy, scaly rash. It’s the most common type of eczema, and it effects more than 18 million American adults (8).

With this in mind, researchers from Copenhagen tested the effects of SLS on individuals with atopic dermatitis (7).

The study consisted of 28 individuals with AD, and 28 healthy controls.

To track results, the researchers collected data on basal transepidermal water loss, skin thickness, blood flow, and skin color before and after exposure to SLS.

The results showed that participants with AD experienced higher levels of water loss and increased skin thickness than the controls.

This indicates that SLS can cause further irritation in individuals with AD and other skin sensitivities.

Sodium Laureth Sulfate (SLES)

Just like SLS, Sodium Laureth Sulfate (SLES) is a surfactant that is added to products to increase their foaming action. And also just like SLS, it’s a proven irritant (9).

Study: Final Report on the Safety Assessment of Sodium Laureth Sulfate and Ammonium Laureth Sulfate (2010)

In 2010, the Cosmetic Ingredient Review (CIR) Expert Panel was tasked with investigating the safety of SLES and related ingredients as they’re currently used in cosmetic products (9).

SLES and related ingredients have been shown to cause irritation to the eyes and skin, though they’re often formulated in such a way as to reduce this risk.

As stated by the panel, SLES can:

”produce eye and/or skin irritation in experimental animals and in some human test subjects; irritation may occur in some users of cosmetic formulations containing these ingredients.”

And while this is a possibility, the panel also claims that such ingredients:

“are safe as cosmetic ingredients in the present practices of use and concentration when formulated to be nonirritating.”

For individuals with sensitive skin, this means SLES-containing products – of which there are thousands – should be avoided to prevent further irritation of your condition.

Citric Acid

Citric acid is an ingredient found in both foods and cosmetics. It’s most often used as a pH adjuster and fragrance ingredient (10).

Study: On the Safety Assessment of Citric Acid, Inorganic Citrate Salts, and Alkyl Citrate Esters as Used in Cosmetics (2012)

The CIR was once again tasked with determining the safety of citric acid, as well as inorganic citrate salts, and alkyl citrate esters as they’re used in cosmetics (11).

The main concern was with topical applications of the ingredients, though aerosolization of the ingredients were also considered.

As highlighted by the review, citric acid has been shown to be irritating to the skin and eyes. The level of irritation varies by concentration, with some human subjects experiencing itching and stinging in as little as 3 percent concentrations.

However, the panel concluded that:

“available repeated insult patch testing at the highest leave-on concentration of 4% citric acid demonstrated an absence of both dermal irritation and sensitization, suggesting that these ingredients would not be irritants in formulation.”

But as previously stated, irritation can occur in smaller percentages depending on the individual.

If these ingredients cause so much harm, why are they used?

The simple answer is that they prolong the shelf life of the product, while also creating a ‘classic’ shampoo smell and feel.

But these ingredients aren’t necessary to the health of your hair and, in fact, they can cause significant damage.

The Best Natural Shampoo Ingredients

There are many shampoos on the market that claim to contain only the best natural ingredients. However, ‘natural,’ as it’s commercially used, is far from an accurate definition.

But even if these products do contain natural ingredients, there are still underlying chemical agents – including dyes and waxes – that can cause harm.

This is why the best natural shampoos are those with plain, simple ingredients. There are no preservatives or drying alcohols – just plant, mineral, and microbial ingredients as nature intended them to be.

So, what ingredients should you look for?

Apple Cider Vinegar

Achieving and maintaining the right pH balance on your scalp can be tricky. This is especially true after years of store-bought shampoo usage.

Fortunately, there are natural ‘cleansers’ that work to bring balance back to the scalp gently and effectively. One such cleanser is Apple Cider Vinegar (ACV).

ACV can be applied to the face, scalp, and hair either directly or after its been diluted.

It cleanses any buildup – including dirt, dead skin cells, and leftover cosmetic products – without stripping your skin of its natural oils.

Malic acid, a component of ACV, has also been shown to contain antibacterial properties which contribute to its use as an antimicrobial agent (12). This means ACV may be helpful in the treatment of fungal and bacteria infections, both of which may promote hair loss.

Coconut Oil

Moisturization and hydration as important to the scalp as they help to maintain balance. And one of the best oils you can use for this task is coconut oil.

Coconut oil is widely found in cosmetics, including lotions, face creams, and shampoos and conditioners. And this is for good reason. It does have numerous studies backing its benefits, after all.

Study: Quantitative measurement of the penetration of coconut oil into human hair using radiolabeled coconut oil (2012)

The ability for an oil to penetrate the hair shaft is highly indicative of its effects on hair strength and restoration. In 2012, Indian researchers put coconut oil’s penetration abilities to the test (13).

One 10-centimeter strand of hair was heated in the presence of tritium gas (a radioactive element) and then soaked in coconut oil.

The strand was split into three separate samples, and measurements of the hair strand were taken at one hour and six hours.

Using the radioactive nature of the hair strand, the researchers were able to determine the percentage of penetrated oil within the samples.

As the results showed, hair submerged in coconut oil for one hour can absorb as little as 14.5 percent of their total weight in oil or as much as 21.5 percent. In the six-hour sample, this jumped to as little as 20.4 percent of their total weight or as high as 26.3 percent.

One of the greatest benefits of coconut oil’s absorption rates is its ability to protect against protein loss.

Study: Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage (2002)

Protein is of great importance to the health of hair, as two major components of hair are keratin (a protein) and collagen (an amino acid) (14). The loss of protein can mean loss of strength and flexibility, and an increase in the chances of breakage.

Researchers from Mumbai, India performed a study that aimed to determine which of three oils – mineral, sunflower, or coconut – would prevent the most damage and protein loss (15).

After determining that coconut oil was the most protective of the oils, its effects were tested.

Four hair types were used, including straight, wavy, and curly (all of Indian origin) and DeMeo (provided by a producer of human wigs).

Each of the four hair types was subjected to different treatments. These included:

• Undamaged control
• Undamaged/coconut oil
• Bleached
• Coconut oil/bleached
• Bleached/coconut oil
• Boiling water
• Coconut oil/boiling water
• Boiling water/coconut oil

Once the hair was treated, they were subjected to a 20 percent concentration of sodium laureth sulfate. They were then examined for various qualities, including protein loss.

Whether the hair was undamaged, bleached, or even boiled, those that were pretreated with coconut oil had the least amount of protein loss and breakage.

The researchers declared:

“the superiority of the protective effect of coconut oil on hair damage in grooming processes when it is used as a pre-wash conditioner as compared to mineral oil and other vegetable oils such as sunflower oil.”

These results are believed to be due to coconut oil’s hydrophobic nature.

This is also why coconut oil is thought to be a great addition to homemade, natural shampoos for dry hair.

Peppermint Oil

Peppermint is a plant hybrid of watermint and spearmint. It’s used in a large variety of daily products including toothpaste, shampoos and body washes, lotions, candles, mints and gums, etc.

And while the minty scent and flavor likely play a role in its popularity, its proven health benefits may contribute as well.

Namely, peppermint oil has been shown to be antifungal and antibacterial, as well as anti-inflammatory (16, 17).

These properties can be used in various formulations to treat an array of conditions, and as the results of a recent study show, possibly even hair loss.

Study: Peppermint oil promotes hair growth without toxic signs (2014)

In 2014, researchers used mice to determine the effects of peppermint oil on hair growth (18).

Twenty male mice were split into four groups. They each had their dorsal areas shaved (to induce telogen phase), and were given a topical application of one of the four substances:

• Saline
• Jojoba oil
• 3 percent minoxidil
• 3 percent peppermint oil

The substances were applied to their corresponding groups six days per week for four weeks total.

Photographs were taken at baseline and weekly thereafter, and skin biopsies were obtained at the end of the study.

As researchers expected, the minoxidil-treatment group saw significant hair growth starting at week 2. However, the peppermint essential oil group also saw significant growth.

In fact, the results between the minoxidil and peppermint oil groups were quite similar.

As the researchers concluded:

“our experimental data suggest that 3% PEO facilitates hair growth by promoting the conservation of vascularization of hair dermal papilla, which may contribute to the induction of early anagen stage.”

They further indicated that, because PEO is believed to “stimulate[] hair growth in an animal model via several mechanisms” the oil “could be used as a therapeutic or preventive alternative medicine for hair loss in humans.”

Caffeine

Caffeine is a stimulant most often enjoyed in the form of a cup of coffee, but its use as a topical stimulant has been around for years. It’s increasingly being used in face masks, lotions, and under-eye creams (19).

But what you may not know is that caffeine may also be one possible solution to hair loss.

There are various studies that back caffeine’s use in the promotion of hair growth. The most recent study, published in 2014, aimed to understand the exact mechanism by which it works.

Study: Differential effects of caffeine on hair shaft elongation, matrix and outer root sheath keratinocyte proliferation, and transforming growth factor…of the hair cycle in male and female human hair follicles in vitro (2014)

Researchers collected male and female hair follicles, which were then dissected and treated in one of two concentrations for 120 hours: one containing testosterone alone, and the other containing both testosterone and caffeine (20).

The researchers used histomorphometry to measure the effects on the hair follicles.

The results of this study left us with three important findings.

First, caffeine was shown to promote follicle elongation.

Second, the caffeine stimulated hair matrix keratinocyte proliferation which is essential to healthy hair growth.

And third, caffeine prolonged anagen duration which is critical in individuals with conditions such as AGA.

The study also showed that caffeine effects male and female follicles differently.

Researchers observed that female hair follicles were more sensitive to the caffeine which means lower concentrations may be just as effective in females as the higher concentrations are in males.

Olueropein

Olive oil is a dietary staple, but it also contains various components that can be helpful in the promotion of strong, healthy hair. One such component is oleuropein.

Oleuropein is a plant-based compound that is found in green olives, olive leaves, and argan oil. It offers a number of positive health benefits, but one of particular importance of those with hair loss is its proven ability to induce anagen hair growth (21).

Study: Topical application of oleuropein induces anagen hair growth in telogen mouse skin (2015)

Researchers from Yonsei University and the University of Ulm conducted a study to determine the effects, if any, that topical oleuropein would have on mice (22). More specifically, they were interested to learn whether the compound could activate the Wnt/β-catenin signaling pathway to induce anagen phase hair growth.

Twenty-four mice were split into three groups of eight. Their dorsal skin was shaved at eight weeks of age to standardize telogen phase.

The three groups were then given a daily application of their corresponding treatment.

Group one received a control substrate, group two received substrate plus 0.4mg of oleuropein, and group three received substrate plus 3mg concentration of minoxidil.

The control contained 50 percent ethanol, 30 percent water, and 20 percent propylene glycol.

The topical applications continued for 28 days, and photographs and hair length measurements were taken on days zero, seven, 14, 21, and 28.

As was suspected, the oleuropein group saw significant hair length improvements over mice in the control group. However, the results also showed that oleuropein outperformed minoxidil over the period of four weeks.

The researchers summarized:

“our present findings indicate that topical oleuropein administration at a dose of 0.4 mg per mouse induces anagenic hair growth in telogenic C57BL/6N mouse skin.”

And while these results do seem promising, they also advise that:

“additional research is required to further determine the potential for developing oleuropein as a pharmacologic strategy for promoting hair growth.”

How Often Should You Shampoo for a Healthy Scalp and Hair?

While evolution may have intended for us not to shampoo, or to do so infrequently and only with the most natural ingredients, there’s no doubt that shampooing has become a societal expectation.

But this expectation can result in over shampooing the scalp which comes with its own set of problems.

In short, you want to avoid removing the scalp’s protective layer as much as possible (23). This means reducing the number of times you shampoo.

Unfortunately, there’s no ‘right’ answer as to how often to shampoo for best results.

Using no shampoo at all would be the best, but it’s not for everyone. So, here are a few factors to consider when making your decision.

Hair Texture

Whether your hair is straight, curly, or anywhere in between, sebum is produced at the base of the follicle and then distributed throughout the strands. However, the texture of your hair can determine how well – and how quickly – this disbursement happens.

Men and women with straight hair will find that their hair becomes oily more quickly, as sebum is able to travel down the hair strands with minimal efforts.

Those with curly or coarse hair, though, will find that their hair may be on the drier side for much longer.

With this in mind, you should aim to wash your hair less frequently the more curly your hair is to avoid over drying.

Skin Type

Skin type is often used when trying to determine the best face wash or foundation. However, determining whether you have a dry, oily, or in-between skin type can also be useful when deciding how often to shampoo.

For individuals who produce less sebum than ‘normal,’ it’s best to wash your hair infrequently. Two times per week at most is best.

This will prevent over-drying, which can lead to other issues including breakage and hair thinning down the line (23).

If you produce more sebum than usual, you’ll also want to limit how often you wash.

By washing too frequently, you’re stripping the scalp and hair of its natural oils. This causes the sebaceous glands to produce even more sebum, which perpetuates the cycle.

To break this cycle, you should stick to washing three times per week maximum.

Lifestyle

Styling and activity level play a major role in how often you’ll need to wash your hair (23).

For men and women who have over-processed their hair with hair dyes, perms, and heated styling tools – you should shampoo your hair as little as possible.

Overstyling the hair causes physical strain on the strands, which leads to premature thinning and breakage. Shampooing too often will just add to this strain.

But for those with high activity levels, you may find yourself need to cleanse your hair more often.

Sweat and dirt can build up more easily in those who are more active, and it’s important to remove it to prevent blockage of the follicles.

One way to do so is by rinsing under lukewarm water and massaging your scalp to remove any sweat and dirt without the use of shampoo. You can then use a cleansing agent, such as ACV, once or twice per week to remove any build up without stripping the oils.

Conclusion

While the scalp can sometimes seem to be a delicate environment, it’s actually adapted to care for itself over hundreds of thousands of years of human evolution.

This means that many of the routines we’ve established to care for our hair – including daily shampooing and regular conditioning – are actually causing more harm than good. And that doesn’t even account for all of the drying and damaging preservatives and detergents found in modern hair care products.

Fortunately, there are ways to prevent further damage to your scalp and hair and even reverse the damage that has occurred over the years of commercial shampoo usage.

You can switch to natural shampoos and hair products – those that contain just plant- and mineral-based ingredients – and allow your scalp to do the job it was created for.

Even further, you can reduce the number of times that you shampoo on a weekly basis and bring your scalp back to its naturally balanced state.