The pH of Skin

The surface of human skin has a naturally acidic pH in the range from 4-6, probably averaging 4.7. This acidic nature of skin is called the acid mantle and is vital for the proper functioning of skin. The low pH helps to protect the skin from bacterial infection, protects the barrier function of skin and helps the skin enzymes function properly. If the pH varies greatly, skin problems arise which may include infection, dehydration, dermatitis, roughness, acne, irritation, and noticeable flaking.

For a refresher, the pH refers to the concentration of hydrogen ion. It is a logarithmic scale that goes from 1-14 with 7 being neutral, less than 7 acidic and higher than 7 alkaline (basic). The pH of a solution can be measured with a pH meter, pH of skin is more difficult to measure and requires more specialized equipment. Read more here.

 What can affect the skin's pH?

The most common thing that we do that can change the pH of the skin is cleansing the face with soap or other cleansers that have a high pH. Healthy skin can come back to its normal pH after a few hours, but not all skin can tolerate that challenge. Face toners are often used after cleansing to restore the skin pH back to acidic. Toners should always have an acidic pH for that reason. I like to use herbaldistillates/hydrosols for a toner.  Modern face cleansers though are typically not soap and are buffered to be an acidic pH. Soap however has a basic pH of about 10 which cannot be changed, that may work great on most of your body, but if you have problems with skin on the face, do not use soap there. You can find a good face cleanser here that is pH balanced to skin.

People have often asked me about cleaning their face with baking soda. This is a big no no because baking soda has a high pH between 9-10 (similar to soap) and is sure to disrupt the pH balance of skin due to its alkalinity. Even plain tap water can affect skin pH. Theoretically, tap water should be pH 7, but it is typically closer to pH 8 because of impurities.

Age also affects skin pH, increasing as we age. For this reason it is important that products for mature skin have a pH from 4-5. Skin moisture, sweat, sebum, anatomic site, and genetic predisposition also affect skin pH.

The skin's pH is maintained by secretions from the glands of the skin; both eccrine and sebaceous secretions.

Understanding the anatomy and function of skin can help you be a better formulator. If you would like to learn more, download our ebook “The Nature of Skin.”

Benefits of Vitamin C for Skin Health

Vitamin C is not made by our bodies and so it must be ingested. Rich sources include citrus fruits, peppers, parsley and berries. Vitamin C is a water soluble vitamin and so it is not found in oils. Although rose hips may be a good source of vitamin C, the oil extracted from rose hips is not a source of vitamin C as many claim. 

Signs of Vitamin C deficiency are follicular hyperkeratosis (rough, raised bumps), petechial hemorrhages (red marks), swollen or bleeding gums, and joint pain.

Vitamin C is also known as L-ascorbic acid and it likes to work with flavonoids for full activity. Its actions include:

1. It is a cofactor for the enzyme lysyl and prolyl hydroxylase. These enzymes are necessary to form the three dimensional structure of the skin matrix protein, collagen. Improving collagen leads to firmer skin.

2. Vitamin C inhibits the enzyme tyrosinase which results in decreased production of melanin. This helps reduce pigmented age spots on the skin.

3. Vitamin C is an antioxidant and inhibits lipid peroxidation and DNA damage caused by UV light. In doing so it also helps protect against UV induced skin damage.

 

4. Vitamin C inhibits the release of pro-inflammatory cytokines including IL-1α, IFN-γ, IL-8, IL-2, TNF-α, and eotaxin  as well as CRP. This may result in decreased reddening and irritation of the skin.

5. Ascorbic acid participates in the synthesis of carnitine. (β-hydroxy butyric acid). Carnitine is an antioxidant, is thought to firm the skin and is involved in the production of energy from fats.

6. Ascorbic acid is involved reactions necessary for activity of oxytocin; the love hormone that is stimulated by skin to skin contact.

For a face care product that has vitamin C try Springtide Gold by Colorado Aromatics.

Anti-Inflammatory Herbs

Feverfew

Borage

Our skin experiences damage both from within and from environmental factors which lead to inflammation. the pathways involved in this inflammation may be involved in promoting the signs of aging in skin. Antiaging formulas for the skin should therefor contain ingredients that act as anti-inflammatory agents. Following are some herbs that have anti-inflammatory activities that can be used in skin care products.

Antiinflammatory Herbs Used in Skin Care

Aloe vera (Aloe Barbadensis)
Borage (Borago officinalis)
Calendula (Calendula officinalis)
Chamomile (Matricaria recutita and Chamaelelum nobile)
Comfrey (Symphytum officinale)
Cornflower (Centaurea cyanus)
Fennel (Foeniculum vulgare)
Feverfew  (Chrysanthemum parthenium)
Frankincense (Boswellin)
Ginger (Zingiber officinale)
Green Tea (Camellia sinensis)
Holy Basil (Ocimum tenuiflorum)
Hops (Humulus lupulus)
Lavender (Lavandula angustifolia)
Licorice root (Glycyrrhiza Glabra)
Mint (Mentha spp.)
Pansy (Viola tricolor)
Plantain (Plantago lanceolata)
Red clover (Trifolium pratense)
Rosemary (Rosmarinus officinalis)
Sage (Salvia officinalis)
Turmeric (Curcuma longa)
White Willow (Salix alba)
Yarrow (Achillea millefolium)

Frankincense Review

I was surprised today to find a medical review of the esteemed Christmas herb, frankincense, in the British Medical Journal (December 17). Not only is it famed for having been one of the gifts of the Magi, but it is an important medicinal herb, incense and perfume ingredient.

As incense it has been used in religious ceremonies by Jews, Greeks, Romans, Arabs and other ancient religions and is still used today in the Catholic Mass. Frankincense, also called olibanum is the gum resin tapped from Boswellia (Boswellia serrata mainly) trees found in Arabia, Africa and India.

Forty seven studies met the criteria for inclusion in this systematic review done by E. Ernst at the Universities of Exeter and Plymouth in the UK. Inclusional studies had applications to asthma, rheumatoid arthritis, Crohn’s disease, osteoarthritis and collagenous colitis. What all these diseases have in common is that they are all related to inflammation. All studies showed clinically positive results leading the authors to conclude that collectively these results are ‘encouraging but not compelling’. They note that not enough of these studies were large, randomized controlled trials.

Frankincense has traditionally been used to treat diseases of inflammation as well as to promote digestion and used as a skin restorative. Active ingredients in frankincense such as alpha and beta boswellic acid have been shown to affect the pro-inflammatory enzymes lipoxygenase and cyclo-oxygenase as well as the compliment pathway. The lipoxygenase enzyme will convert essential fatty acids into leukotrienes which are can contribute to the inflammatory response in a number of ways. Cyclooxygenase (COX) promotes the formation of prostaglandin H2, another inflammation mediator, from arachadonic acid.

So although frankinsence is probably not the fountain of youth as many websites might have you believe, extracts from this resin certainly may play an important role in preventing inflammatory or treating inflammatory diseases.

Ernst, E., Frankincense: systemic review. BMJ 2008;337.