The body is composed of trillions of cells.  The function of every cell is dependent on the pH of the skin and the body.  The pH equation of health is the perfect balance between the body’s internal pH and the skin’s external pH.  Survival depends on the body’s ability to maintain pH balance (homeostasis).  The body and skin are very sensitive to their pH levels.  Outside the pH range compatible with life, the skin loses its ability to protect the body from environmental damage, enzymes lose their ability to function, and the body is unable to sustain organ system function.  The pH is tightly regulated by a complex system that works to maintain an acidic skin pH and an alkaline pH for the body.  The body and skin’s pH management system regulates circulation, breathing, kidney function, liver function, digestion, hormone function, immune system function, and the skin’s hydration control and barrier function.  The management system is based on cellular communication as all cells have a certain function and the regulatory authority that controls the skin and body’s function is the pH.   With age the efficiency of this pH regulating system decreases.  The health of the skin and body is determined by products applied to the skin, by fluids we drink, by the food we eat, and by the air we breathe.  The skin protects your internal clock against the aging process and you are the time-keeper.

All the regulatory systems and molecules (antioxidants, kidney cells, liver cells, etc.) serve the purpose of balancing the pH of the skin and body.  The skin and body need to neutralize chemicals (free radicals) that alter their pH.  Focus on maintaining healthy skin, not waiting for damage to occur.  Be an active participant in the health of your skin and body.

We protect our skin and eat to live, we do not live to sun tan and eat.  We should shift our perspective from tan and unhealthy diets to understanding the skin’s important functions and our diet’s role in maintaining a healthy pH environment which is essential for life.

One could say the pH is the thermostat that controls the “weather” of the skin.  The pH is the most important chemical feature of the skin and body.  Most physicians know serum pH is 7.35 +/- .05 and that any change outside the normal range is abnormal and at some point cannot support life.  Serum pH below 7 represents serious acidosis and serum pH above 7.5 represents serious alkalosis.  If one assumes the pH of the skin is the same as serum pH, they would be wrong.  It is important to educate everyone about this unknown and misunderstood value.  I am going to answer the important questions.  What is the pH of the skin?  What creates the pH of the skin?  Why is the pH of the skin important?  Why is the pH of cosmeceutical products important?


It is important to understand the fundamentals of pH and how the skin and body regulate the acid-alkaline balance on a minute to minute basis.  The body’s pH is regulated by intracellular fluid (fluid found in all cells and makes up about two thirds of the total amount of fluid in the body) and extracellular fluid (fluid found outside cells and is composed of plasma in the blood stream and interstitial fluid which surrounds tissues).  Your body needs to maintain a pH of 7.35 to 7.45 for your cells to function properly.  Your skin needs to maintain a pH of 4.5 +/- 1.0 for skin cells to function properly.  The proteins in the skin and body are unique and proteins must maintain a specific geometric shape to function and they are affected by the tiniest changes in pH of the skin and body.

There are three main forces at work on a daily basis that influence the pH of the skin and body.  They are the environmental injuries to the skin, the acid or alkaline effects of the food and liquids ingested, and the waste products produced by the metabolic activity of our cells.  Fortunately, there are three major mechanisms at work to prevent these activities from shifting the pH of your skin and body outside their normal ranges.  They include molecular buffering systems in the skin and body, elimination of carbon dioxide by the lungs, and urinary excretion of toxins.

The molecular buffering systems guard against sudden shifts in pH.  This system uses a combination of the skin and body’s naturally occurring antioxidants, enzymes, weak acids and weak bases to minimize changes in the skin and body’s pH.

Elimination of carbon dioxide occurs in the lungs.  Carbon dioxide is mildly acidic and as it accumulates in the blood, the pH of the blood decreases (acidosis).  The brain regulates the amount of carbon dioxide that is exhaled by controlling the speed and depth of breathing.  Thus, an accumulation of carbon dioxide in the blood will initiate faster and deeper breaths raising the pH of the blood into a normal range.  This mechanism is very sensitive and rapid, controlling pH on a minute to minute basis.

Urinary excretion of acids and bases help control the body’s pH.  The kidneys make these adjustments much slower than the lungs, generally, taking several days.

To understand the importance of the skin and body’s pH, one must be able to define pH and understand the definition.  The word pH is a chemistry term. But that doesn’t mean it can’t be understood! A pH number indicates the acidity or alkalinity of a solution (a liquid composed of ingredients).

In a definition of pH, “pH” stands for “potential of hydrogen.” The “H” is capitalized because the symbol for hydrogen is capital H.

“Skin pH” is a chemist’s term and is used to measure the degree of acidity or alkalinity in the outer skin layers. It is measured on a scale ranging from 0 to 14 where the center of the scale (7) is neutral (neither acid nor alkaline). A reading below 7 indicates that the substance being measured is acidic and above 7 is alkaline.

It is important to understand that on a pH scale, each number represents a tenfold difference from adjacent pH numbers.  That is a pH of 6 is ten times more acidic than a liquid that has a pH of 7 and a liquid with a pH of 5 is one hundred times more acidic than a pH of 7.  Most coffee has a pH of about 3 which makes it about ten thousand times more acidic than a pH of 7.

Normal skin pH is somewhat acidic and in the range of 4.5 +/- 1.0. It varies from one part of the body to another and, in general, the pH of a man’s skin is lower (more acidic) than a woman’s. The coating on the skin is a combination of sebum (oily fats), glandular secretions, perspiration, and cellular material called the “acid mantle” layer.  The acid mantle layer is constantly secreted to cover the skin’s surface and maintain a proper skin pH.

The acid mantle protects skin in several ways:

Antioxidants – The lipids (fats) in the mantle are sacrificially oxidized to protect the underlying skin from excessive oxidation. This is why “whiteheads” – which are un-oxidized sebum in pores – turn into “blackheads” as the sebum is oxidized.  Antioxidants help neutralize free radicals that cause oxidation.

Water Repellent – The fats in the mantle repel water from the skin just like the oil on a duck’s feathers repels water. This keeps water from loosening and damaging the outer-most skin layers and renders the skin less vulnerable to damage and attack by environmental factors such as sun and wind and less prone to dehydration.

Bacterial Inhibition – The acidic pH of the mantle inhibits bacterial growth on the skin. Thus, the skin remains healthier, and has fewer infections and blemishes.  

Maintains Protein Hardness – The outer skin proteins are made of keratin, a very hard protein, that is also used in nature to make horns on animals. Keratin must be kept at an acidic pH to maintain its hardness by keeping the protective proteins tightly bound together. More alkaline pHs soften and loosen the fibers of keratin and create gaps in the protective covering. This allows more allergens, irritants, bacteria and viruses to penetrate into the skin.

This is essential to our health because the body only operates well at a balanced pHour bodies need both acidic and alkaline substances to function well, but they need to be balanced. The pH scale is a tool we can use to monitor our health because it will show us whether our body is too acidic, too alkaline or just right and balanced.

One of the most important roles of our skin is to protect our ‘insides’ from the external environment, acting both as a barrier and a filter between the ‘outside’ and ‘inside’. In addition, the skin is involved with immune function, temperature regulation, sensation, storage of molecular compounds, eliminating toxins created by cell metabolism, synthesis of molecules, and determines our physical characteristics.



There is a change in skin pH with age.  At puberty, however, we start to produce more hair on our bodies. Hair follicles have an associated sebaceous gland or glands which become active as hair growth increases, causing changes in the skin’s pH. The hormones that control sweat also become active and the whole surface of a teenager’s skin is totally different to that of a young child. This is our body’s way to increase our defense system.

The pores of our skin are made up of a combination of oil and sweat glands (sebaceous and sudoriferous glands) helping to keep our skin healthy and elastic.   When in balance, the combined excretion of oil, celluar material sweat from the skin has a pH of 4.5 +/- 1.0.

In the late teens to early 20’s, our Acid Mantle Layer is well developed and provides good protection against potentially harmful, external environmental factors. Our skin usually looks healthy, heals quickly, and when injured seems to take care of itself.

With increasing age however, the skin’s pH becomes more and more neutral, and thus more susceptible to bacterial growth, sun damage, smoking, and other pollutants. This reduced acidity kills fewer bacteria, neutralizes less free radicals, and loses moisture content, leaving the skin susceptible to bacterial growth, aging, and dry skin. The skin weakens as a result and begins developing problems with increasing age. (Interestingly, the pH value rises beyond 6 when a person actually suffers from a skin problem or skin disease.)

The aging process of the skin causes biochemical changes in collagen and elastin, the connective tissues underlying the skin, which give the skin its firmness (collagen) and elasticity (elastin). The rates of loss of skin firmness and elasticity differs from individual to individual, depending on their genetic makeup, general health, over exposure to the sun, skin care regime, or lack thereof, and other factors.

As the skin becomes less elastic, it also becomes drier; the underlying fatty tissue begins to disappear resulting in the skin beginning to sag. Our skin is less supple, and wrinkles begin to form. At this stage, our skin is more easily injured, heals more slowly, and tends to dry out more quickly.

Another factor that helps in regulating your skin’s pH is the presents of microflora on your skin. Staphylococcus epidermis is involved in the breakdown of fatty acids, and is therefore partly responsible for the acidic pH of skin. The use of ordinary soap, not only changes the pH of the skin to be more alkaline, effectively removing the protective acid mantle layer, but also kills the bacteria responsible for creating, at least in part, the acidic pH of your skin – a double whammy.

It is therefore of great importance to have a good skin care regime in which high quality, scientifically advanced skin care products are employed.

The water you drink, the air you breathe, the amount of sunlight you are exposed to, how well you sleep, the amount of stress in your life, and how often you get physical exercise, can have a profound effect on the pH level of your body. This will affect how healthy you are and how long you will live.

The skin is the largest organ of the body making up nearly 15% of the total body weight.  Skin is amazingly complex and well designed.  Skin is a multipurpose organ providing numerous functions, many we take for granted.  The skin is flexible and elastic, it protects us from environmental stresses (sun, pollutants, wind, cold, etc.), provides us with sensation as there are thousands of nerve endings per square inch, maintains and protects our internal organs, and controls its pH in order to maintain healthy skin.

The pH is the thermostat that controls the climate (environment) of the skin.  Normal skin pH is essential for epidermal cell function, normal skin flora, molecular integrity especially enzymes and antioxidants, and normal skin hydration.  It is critical to maintain and restore skin pH for normal skin function and collagen synthesis.

Insults, such as, sun, tanning beds, pollutants, cigarette smoke, radiation, change in diet, hormones, excessive washing, and poor skin care products alter and damage the pH of the skin.  Altered pH results in skin irritation, acne, skin infections, and accelerated skin aging characterized by rough skin texture, large pores, poor skin tone, blotchy skin color and wrinkles.

This emphasis the importance of skin pH but the pH of skin care products is equally important.

The pH regulates the biologic activity, concentration, potency, and clinical benefit of cosmeceutical skin care products.  The pH influences the free acid concentration, “the biologically active form,” of all the important molecules present in the skin.  This directly affects the biologic activity of glycolic acid, alpha lipoic acid, enzymes, L-ascorbic acid, retinol, peptides, lipids, and other molecules.

Glycolic acid in a solution, lotion, or cream exists in a free acid form HOCH2CO2- and a bound form HOCH2CO2H.  There is equilibrium between the free acid form and the bound form in a product which is pH dependent.  However, the bound form is not biologically active.  The free acid concentration of glycolic acid is determined by the pH of the skin care product or glycolic acid peel.  Obviously, a product could state the free acid concentration and the pH which is the standard used by Rx Systems PF.  However, if one knows the total glycolic acid concentration and pH of a product, the free acid concentration can be determined using the free acid concentration of glycolic acid based on pH curve (glycolic acid dissociation graph).

The free acid form of glycolic acid represents the biologically active molecule.  The lower the pH of a product, the greater the percent free acid concentration of glycolic acid in that product.

Let’s examine the glycolic acid dissociation curve which is the same as the free acid concentration of glycolic acid as it relates to pH curve.  The bottom of the chart represents the pH of the product.  The left side of the chart represents the percent of free acid in the product but one must know the total free acid concentration of the product in order to calculate the actual free acid concentration in the product.

There is a product with a total glycolic acid concentration of 24% at a pH of 3.8.  On the bottom line of the chart locate 3.8, and then draw a vertical line to intersect with the dissociation curve, and then draw a horizontal line from that point until it intersects the left side of the graph which is at the 50% free acid form.  In the example above, there is a product with a total glycolic acid concentration of 24% and a pH of 3.8.  The calculated free acid concentration is 12%.

It is important to note that every individual molecule has an ideal range of free acid concentration and pH combination to maximize penetration, potency, and maximum clinical benefit.

When a product is not buffered, the more glycolic acid or other acid added to the product, decreases the pH and increases the free acid concentration, strength, clinical effectiveness, and results.  However, there is a balance because there is a level where the acidic pH alone can denature epidermal proteins creating skin irritation.  Therefore, an acidic pH less than 2 intensifies the effect of glycolic acid peels; however, with glypoic complex skin care products it is important to maintain a pH above 2.5 to eliminate the unwanted irritation and peeling of products used on a daily basis.

When a product is buffered, there is a base or salt added to the product which increases the pH of the product, decreases the free acid concentration of the product, and resists change in the free acid concentration when you add extra acid to the product.  For example purposes I am going to use sodium hydroxide (NaOH) as the base in a product to buffer the product.  With the higher pH (generally 3.8 or higher) you have some free glycolic acid HOCH2CO2- but more buffered glycolic acid (sodium glycolate) HOCH2CO2-Na+ (not biologically active) and bound glycolic acid HOCH2CO2H (not biologically active).  This creates a product which eliminates any irritation from the acidic pH (as it creates and maintains a higher pH of the product) of the preparation but also eliminates the benefits of glycolic acid or glypoic complex as it diminishes the levels of the free acid form needed for clinical benefit.

This emphasizes the fact that epidermal and dermal molecules are dramatically altered by pH.  Every molecule has its ideal range of pH and free acid concentration.  The pH determine the bioavailability and the biologic activity of these molecules (enzymes, antioxidants, peptides, and lipids).  Biologically active molecules have a positive (+) or (-) charge at its active site to bind to receptors which initiates a biologic reaction.

An understanding of biologic reactions is necessary to appreciate the fact that molecules exist in an active and inactive form.  Biologically active forms of a molecule exist in an active state with a biologic charge, either a negative (-) or a positive charge (+).  Biologically inactive forms of a molecule are bound and have a neutral or no charge.  A biologic receptor also has a negative (-) or positive charge (+).  One must remember that opposite charges attract one another   (-:+) and like charges repel one another (-   -) or (+  +).  A neutral charge or no charge has no attraction or affinity.  Let’s examine a biologic reaction.  There is a biologically active molecule and for example purposes L-ascorbic acid will be the model.  There is a cellular receptor for L-ascorbic acid with a (+) charge and the biologically active form of L-ascorbic acid has a negative (-) charge.  The opposite charges attract one another and the active molecule and the receptor attach to one another (L-ascorbic acid -:+ Receptor for L-ascorbic acid).  In the case where this receptor is cell bound, the attachment of the L-ascorbic acid to the receptor sends a message to the cell to stimulate collagen synthesis.  All biologically active molecules are like keys and the receptors are like the locks.  Therefore, in our example the active L-ascorbic acid with its negative charge (-) represents a key with a very specific pattern.  The receptor with its positive charge (+) represents a key hole, also, with a very specific pattern which will only turn on when the specific key is engaged.  That means that all negative charged and positive charged molecules have different key patterns and the same uniqueness exists for their receptors with negative and positive charges.  Remember, all negatively (-) charged biologically active molecules will only insert into a specific pattern, positively (+) charged receptor.  Vice versa, all positively (+) charged biologically active molecules will only insert into a specific pattern, negatively (-) charged receptor.   Again, this is because opposite charges attract one another and like charges repel one another.  When the specific, active molecule and receptor bind to one another it initiates a biologic reaction.

In other words, the right key for the right lock turns and initiates the biologic reaction.  On the other hand, if you have an inactive, bound form with no electrical charge it will not bind to the receptor because neutral or like charges repel one another.

Your skin is the first line of defense against the aging process and the pH is the thermostat that regulates the speed and progression of this process.  Create the right prescription for your skin based on pH and free acid concentration of active ingredients.  Good health is not a luxury, it is a necessity.  Real science will produce real results.