Selecting skin care products is daunting with the myriad of choices available.

We have to know our skin type, what our problems are, and what ingredients are best for it. Now to compound that, we need to make sure the products are at an acceptable pH to keep our skin in balance and keep it functioning optimally.

I will try to simplify this today and help you assemble a pH balanced skin care regimen.

Understanding pH

What is pH?

pH is a very important measurement in cosmetic chemistry for both formulating products and testing them as well (1). pH is the measure of the concentration and activity of the hydrogen atoms in a solution. It is an acronym for “potential hydrogen” (2).

pH is measured from 0-14, with 7 being considered neutral. The higher the number, the more basic or alkaline the solution. Basic solutions have a lower concentration of hydrogen atoms.

Conversely, the lower the number, the more acidic the solution. Acidic solutions have a higher concentration of hydrogen atoms. Neutral solutions are neither acidic nor basic.

Here are some examples:

• Water is considered a neutral solution (pH of 7)
• Lemon juice and white vinegar are a pH of 2
• Bleach and ammonia for consumer use are a pH of 11

While a one number increase in pH, such as from 4 to 3, doesn’t sound like a big deal, just remember that each one number change actually means a tenfold increase in potency. So small deviances in pH can lead to big problems.

What pH is the human body?

The human body’s pH varies depending on what part of the human body we are discussing (2).

The body cannot function properly if it does not maintain its specific pH. So, our body has built-in mechanisms that try to keep the pH where it needs to be.

• Human cells are a pH of 6.8
• Human blood is a pH of 7.4
• The outer layer of the skin (stratum corneum) is a pH of 4.7-5.4, which gets more basic with each deeper layer
• Stomach is a pH of 1-2

How does pH affect the skin?

Any change in the skin’s pH levels will affect how the skin functions (2). It needs to be slightly acidic. If not, the skin’s defenses will be impaired:

1) Rendering it susceptible to an overgrowth of bad bacteria and fungi, 2) leading to loss of barrier function and increased water loss and dehydration of the skin with possible exfoliation of the skin, and 3) causing irritation and inflammation, which can lead to conditions such as acne and eczema.

Acidity and the skin

What is the acid mantle?

The skin’s acid mantle is the protective film on the outer layer of skin (stratum corneum), which was first studied by Schade and Marchioni in 1928 (2).

It is a complex combination of functioning units of the skin which, protects the skin and keeps it functioning properly.

This combination includes:

• Eccrine sweat glands which secrete lactic acid
• Free fatty acids produced from the resident bacteria that secrete lipase
• Urocanic acid
• Sodium/hydrogen antiporter system

What does the acid mantle do for the skin?

The skin must be maintained in its acid state for the proper functioning and health of the skin (1-3). Here are some things that the acid mantle does:

• Protect against invasion by pathogenic bacteria and fungi and subsequent infection
• Shedding of skin cells
• Pigmentation
• Stem cell behavior
• Prevent inflammatory skin diseases, like acne and eczema

Therefore, it is essential to select products which, keep the skin slightly acidic, so it remains healthy and disease-free.

What affects the pH of the skin

Does tap water affect the pH of the skin?

Depending on what pH your tap water is, it could temporarily change the pH of the skin. The tap water in Europe is about a pH of 8, which is more alkaline than in the US, which is about a pH of 7 (4-5). Seawater and pool water are also alkaline.

People with normal barrier function can tolerate these changes, but it affects patients more if they have impaired barrier function, like eczema patients. Some people believe they should wash their faces with carbonated bottled water, which has a more acidic pH of 5.5; however, more research needs to be done to confirm the benefits, if any.

Does pollution affect the pH of the skin?

When skin is exposed to pollution, it can increase the pH (6). When the pH is altered, it allows deeper penetration of harmful free radicals that are produced by UV rays from the sun. These free radicals damage our collagen and DNA, leading to skin cancer formation.

Pollution also promotes inflammation, increases sebum (oil) production, and the growth of bacteria, like P. acnes, which is implicated in acne breakouts. This increased inflammation can also cause problems with premature aging and eczema flares.

Does aging change the pH of the skin?

Aging skin develops a higher pH, which leads to a decrease in the acidity of the skin (2, 7, 8). Without the skin barrier working correctly in the skin of the elderly, there will be more water loss and more growth of unhealthy microbes. That is why skin gets dry and wrinkled as we get older. This also correlates to more odor from pathogenic microbes as we get older.

Interestingly, newborns have neutral skin pH (2, 7, 8). Newborn skin becomes more acidic within the first months after birth and maintains this until old age, when it gets less acidic.

Does ethnicity affect pH?

The pH of darkly pigmented skin is usually lower than lightly pigmented skin (2, 8-11). This difference is possibly due to underlying skin biology and behavior of melanocytes and melanin granules. The lower pH of darkly pigmented skin leads to less dehydration and less infection.

Does sex affect the pH of the skin?

Men tend to have more alkaline skin than women (2, 12-14). This may even lead to more odor in men because of the increased growth of pathogenic microbes from the alkaline environment.

Do different parts of the body have different pH?

Intertriginous areas, such as the armpits and groin, tend to be less acidic (2). This is due to the fact that these areas have higher moisture (8). Higher moisture = higher pH = more alkaline.

The higher pH allows for the growth of microbes, which can lead to infections and odor (12). Deodorants work best by decreasing the skin’s pH to make it more acidic to kill the pathogenic microbes causing odor and infection (15).

Does sweating change the pH of the skin?

Excessive sweating and higher environmental temperatures raise the skin’s pH, especially in the armpits (2, 16). Mild exercise does not. These alterations in barrier function were transient and returned to normal shortly after ceasing exercise.

Does diabetes alter the pH of the skin?

Patients with diabetes have a higher skin pH, which leads to abnormal skin barrier function (17-19). This higher and more alkaline pH leads to overgrowths of harmful microbes, like bacteria and candida, and ultimately infections.

Diabetic skin also has increase water loss and lower sebaceous gland function that causes dehydration and dryness of the skin. So, the skin of a young diabetic takes on the appearance of an elderly person’s skin.

Does nutrition alter the pH of the skin?

Nutrition can alter the pH level of the skin (2). These can make it more acidic, which is beneficial to the proper functioning of the skin:

• Vitamin A
• Monounsaturated fats
• Increased fluid intake
• Increased calcium intake
• Diets rich in histidine

pH and its role in different skin conditions

How does the change in pH of the skin affect acne and rosacea?

When the skin’s pH is off, it can affect how the skin functions and lead to certain inflammatory and infectious skin conditions, such as acne and rosacea (2). When the skin cells do not shed properly, dead skin cells build up and clog pores leading to acne and rosacea.

Also, if the skin pH is not acidic enough, it cannot kill the bacteria P. Acnes which is implicated in acne formation (2).

Finally, excess androgens, which lead to acne, slow down barrier recovery making it difficult to keep the pH of the skin acidic. So keeping the pH of the skin acidic will help keep acne under control.

How does the change in pH of the skin affect eczema?

It is thought that eczema patients have an underlying impaired barrier function causing a decrease in barrier lipids to protect the skin from dehydration, allowing microbes to penetrate and lead to infection, and causing a dysfunction in the signaling molecules leaving the skin being stuck in a constant inflammatory state (20).

The use of products with a less than optimal pH can worsen these underlying dysfunctions in the skin of eczema patients, which will exacerbate their eczema (20). The change in pH will cause poor barrier function allowing dehydration of the skin through water loss.

It also impacts barrier function against microbes, allowing them to penetrate the skin’s defenses and colonize the skin leading to infections.

pH and skincare products

What is the ideal pH for your skincare products?

In order to keep the skin functioning properly, you need pH balanced skincare products (21-23). Your skincare products should be about a pH of 5.5 to 4.5. Most skincare products today understand the importance of balancing the pH and keeping it at an optimal level.

The skin has a fantastic ability to counteract drastic changes in pH on a temporary basis to restore it to its normal pH (23).

However, continued long-term use of products that drastically change the pH will eventually damage the skin leading to redness, flaking, irritation, dehydration, and inflammation. Alkaline products such as bar soaps are the worst for the skin. They strip away all-natural oils in the skin, giving you a tight feeling on your skin.

They are excellent at cleaning the skin but at a high price. There are better liquid cleansers that keep your pH where it should be.

What are the different types of cleansers?

There are 4 basic types of cleansers for the skin (24). These vary based on their ingredients and what they do to the skin.

1. True soap

Soap is created by mixing fat and alkali and usually has a pH of about 9-10. It is great at removing oil, dirt, and debris from the skin. Unfortunately, they are too good because they strip away natural oils and damage the skin’s proteins.

This damage leads to dehydration and flaking of the skin.

2. Synthetic detergent (syndet)

These cleansers only contain a small amount of soap to minimize damage to the skin and keep the pH of the product around 5-7. These are preferred over true soap for everyone, but especially acne patients.

3. Combination bars (combars)

These combination bars contain soap, syndet, and antibacterial agents. While they get rid of harmful bacteria, they also eradicate the good bacteria we need to keep the skin functioning properly. These can lead to dryness and damage to the skin.

4. Lipid free liquid cleansers

These cleansers have no soap, so they can maintain the proper pH of the skin. They also have moisturizers, which leave behind a thin layer of moisture on the skin to protect it.

They are like hair conditioners which, deposit moisture into the hair. This makes them ideal for eczema patients or the elderly who are prone to dry skin.

What is a surfactant?

Surfactants are ingredients in cleansers that actually do the job of removing dirt and oil (24). The CMC (critical micelle concentration) of a surfactant is the measure of how well it removes the dirt and oil.

Low CMC means a higher cleaning efficacy and thus more damage to the skin. There are 4 types of surfactants: nonionic (stearyl alcohol), amphoteric (cocamidopropylbetaine, anionic (sodium laurel sulfate), and cationic (benzalkonium chloride).

Nonionic is the least irritating, and anionic and cationic are the most. Interestingly, anionic are the most commonly used today because they lather well. Cationic surfactants are primarily used in antibacterial cleansers.

What are the different types of moisturizers?

There are essentially 3 types of moisturizers which, provide hydration via direct or indirect mechanisms (24).

Direct mechanism is by occlusion of the skin to immediately stop the loss of water. In contrast, an indirect mechanism occurs with the addition of an ingredient, like a humectant, which helps retain water slowly over a longer period of time.

1. Occlusives

These agents form an immediate layer over the skin, which will not allow water to evaporate or anything else to penetrate. Petrolatum and mineral oil are examples of occlusives.

2. Humectants

These agents penetrate the skin and bind to and hold on to water so that it does not evaporate. Examples include glycerin, hyaluronic aid, and alpha hydroxyacids (glycolic acid).

3. Emollients

These agents have some occlusive potential while making the skin feel smooth. Examples include glycerol and sunflower oil.

Today, many moisturizers have lipids (fatty acids, ceramides, pseudoceramides, and cholesterol) added to them to help restore barrier function quicker by artificially replacing these lost lipids in the skin. These have shown promising results in eczema patients.

What is an emulsifier?

Emulsifiers are agents added to moisturizers to help mix different ingredients that would not normally mix together (24). Think of oil and water. They are divided into 3 groups: anionic, cationic, and nonionic.

Anionic ones (sodium laurel sulfate) are the most irritating, while nonionic (polyethylene glycol) is the least. Cationic ones (quarternium 15) may cause a problem as well.

Can I test my products to see what the pH is?

You can very simply and easily test the pH of skin care products at home. You can order litmus paper or pH testing strips online to test your products. Litmus paper is a special paper that will tell you whether the product is acidic or alkaline.

Blue litmus paper turns red under acid conditions, and red litmus paper turns blue under alkaline conditions. Neutral litmus turns purple.

pH paper will indicate the precise pH value, not just whether it is acidic or alkaline. The pH strips will change color based on the product being tested. It is a much more accurate way of testing pH.

The pH scale looks like a rainbow with dark red as the most acidic at one end of the spectrum and dark purple at the other end to indicate the most alkaline. Green in the middle represents neutral 7 pH.

The best pH balanced skincare products

What is a good pH balanced cleanser?

These will gently cleanse your skin to remove dirt while keeping your skin pH in the acidic range to maintain barrier function. These are all about 5.5 pH cleansers, except for Cetaphil, which is closer to 4.5 pH.

Neutrogena Ultra Gentle Daily Cleanser

ZELEN Life Cleanser

Dove for Sensitive Skin (liquid)

Cetaphil Gentle Cleanser

Skinceuticals Purifying Cleanser

What is a good pH balanced moisturizer?

These pH balanced face moisturizers will moisturize your skin and help prevent water loss while maintaining the proper pH of the skin.

Vanicream Moisturizing Cream

Cetaphil Moisturizing Cream

ZELEN Life Moisturizer

Cerave Moisturizing Cream

What is a good pH balanced sunscreen?

These are some of the best sunscreens on the market that will protect your skin from the sun’s harmful rays while maintaining the proper pH of the skin.

La Roche Posay Melt In Sunscreen Milk SPF 60

La Roche Posay Mineral Sunscreen SPF 50

What is a good pH balanced exfoliator?

These exfoliators will gently remove dead skin cells without harming your barrier function by maintaining your acidic pH.

ZELEN Life Exfoliator

La Roche Posay Ultra Fine Face Scrub

Skinceuticals Glycolic 10 Renew Overnight Exfoliator

What is a good pH balanced toner?

These low pH toners will help remove dirt and oil while protecting the integrity of the acidic pH of the skin.

Skinceuticals Equalizing Toner

ZELEN Life Toner

Conclusion

It is crucial to select skincare products that are close to the pH of the skin, of around 5.

Prolonged disruptions cause by-products, which alter the skin’s pH and can lead to (or worsen) certain skin conditions. The alteration of the skin’s pH will lead to impaired barrier function, which increases the dehydration of the skin and allows pathogenic microbes to enter the skin and cause infections.

If you do not know what the pH of your products are, you can buy inexpensive pH testing strips and test your products at home.

Do you have any suggestions of products for a well-balanced pH of the skin?

References

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