The Skin's Acid Mantle

Waterproof, washable, stretchable and automatically repairs small cuts, rips and burns? Welcome to your S K I N.

The Acid Mantel is vital to the function of the Stratum Corneum - this is the outermost layer of the epidermis - your skin! Along with it's derivatives - sweat and oil glands, hairs and nails make up a pretty complex set of organs and they are your super power called protection.

The skin forms three types of barriers

ONE Chemical Barrier - Includes skin secretions and melanin. The skins surface is covered with bacteria (skin microbiome) the low pH of skin secretions known as the Acid Mantle decreases their multiplication. Many bacteria are killed by anti-bacterial substances in the sebum. Skin cells also secrete a natural anti-biotic known as 'human defensin'. Melanin provides a chemical pigment shield to prevent UV damage to the viable skin cells. Keratin - is a protein found in skin, hair and nails; it prevents both the loss of body fluid through the skin and entry or excessive water into the body

TWO Physical Barrier -  Is offered by the continuity of the skin and the hardness of it's keratinised cells. The waterproofing of the glycolipids of water soluble subances between cells preventing both water loss from and entry into the body through the skin. Substances that do penetrate the skin in limited amounts (here are some examples) :

  1. Lipid soluble substances such as oxygen, carbon dioxide, fat soluble vitamins A // D // E // K, steriods and some bio-active botanical extracts.
  2. Oleoresins of certain plants (poison Ivy)
  3. Organic Solvents such as acetone, dry cleaning fluid, paint thinner (these dissolve the cells lipids)

THREE Biological Barriers - Langerhans cells in the epidermis and macrophages in the dermis. Langerhans cells - are active elements of the immune system which protect the Dermis against foreign substances (antigens) Macrophages - are the second line of defence and kill viruses and bacteria that have managed to penetrate the Epidermis.

What is the Acid Mantle?

It is an invisible viscous fluid known as hydro-lipid film, it maintains and protects the overall health of skin and hair and is slightly acidic. It comprises:
  • Sebum is secreted by our sebaceous glands and this oily substance is our skin's own moisturiser.
  • A salty watery mixture is secreted by our sweat glands 
  • Skins' microbiome secretions 

These together form the Acid Mantle and have a pH level ranging from 4–6. pH is a measurement of acidity. A neutral pH is 7, anything above that creates an ALKALINE environment, and anything below creates an ACID environment.

SKIN - Consists of three main layers Epidermis, Dermis and Hypodermis: 

diagram of human skin

The Epidermis - is made up of five layers which vary in thickness depending on the area of the body. Facial skin is rather thin compared to the soles of our feet. There are NO blood vessels or nerves in the epidermis. Nutrients and fluid diffuse into it from blood vessels in the Dermis. Both Keratin and Melanin are found in the epidermis.

The Dermis - is a thick layer of connective tissue that includes collagen fibres and elastic fibres providing both flexibility and strength and support the blood vessels and nerves paling through the Dermis. Sensory receptors are found here. Embedded in the skin are sweat and sebacous glands (along with hair follicles and nails) 

Hypodermis Below the epidermis and the dermis lies the Subcutanous tissue or Hypodermis consisting of connective tissue fat cells macrophages fibroblast blood vessels and nerves. 


  • A physical barrier against invasion against micro organisms 
  • Sebum is acidic and inhibits bacterial growth our skins microbiome lives on our skin and acts as a deterrent to invading organisms.
  • Skin prevents excessive fluid loss
  • Has an important role in the regulation of body temperature 
  • Sensory perception agains environmental hazards
  • The synthesis of Vitamin D 

SKIN DISEASE - The microbiome of the skin consists of transient, temporary-resident, and permanent-resident species, including coagulase-negative staphylococci. Normal flora growth (microbiome) is optimal at acidic pH levels, pathogenic bacteria, such as S. aureus, thrive at a neutral pH levels. So there is a good reason why your skin is so acid, because pathogenic bacteria thrive under alkaline conditions.

Disruption of the permeability barrier (Acid Mantle) can cause skin diseases which have been shown to have altered pH levels:
  • Atopic Dermatitis
  • Acne
  • Candidal Intertrigo
  • Diaper Dermatitis (nappy rash)
  • Ichthyosis
  • Tinea Pedis
  • Irritant Contact Dermatitis
  • What can irritate the Acid Mantle?

    UV light, diet, excessive sweating, Skin and Hair Products, Air conditioning, heating, medications and pollution. 

    Facial Cleansers - Can be classifed according to the type of surfactant used. [surfactant are to help a product foam think SLS/SLES] Cleansers with non-soap-based surfactants are known as “syndets” (synthetic detergent-based bars or liquids). Syndets are generally neutral or acidic less than pH 7 compared to soap-based cleansers which are typically alkaline in nature pH 10. Soap-based cleansers are known to have a higher potential to irritate skin than syndets. 

    Even water is too alkaline for skin - After water touches your skin, it’s important to rebalance the pH to a mildly acidic level [using high-quality skin care products]. Many common skin care products, such as cleansers, serums, and moisturizers often have a pH of 5.5 and higher, which can dry out your skin and make it more prone to infections, outbreaks, and premature aging.

    A skin care product’s formula - Helps determine its pH level. Look closely at the label, and if the pH is not listed then contact the manufacturer to find out. You also don’t want your skincare products too acidic (below 4.5). Mild acidity = pH between 4.6 and 5.


    Use an oil cleanser // For your face and always choose a body wash, soap or cleanser that has a pH between 4.5–6.5 (similar to the normal pH of the skin) Remember too that shampoo is a foaming product i.e. it will contain a surfactant. Oil Facial Cleansers - clean without stripping away the skins micro biome or the skins protective Acid Mantle.

    Use a Toner // that DOES NOT contain harsh astringents like Witch Hazel and alcohol [ethyl or denatured alcohols, are damaging to the skin]. Choose a water based toner // hydrosol that is both gentle, hydrating and will rebalance the the pH of your skin after cleansing.

    Moisturise // your skin with Emollients (oils and butters) these help increase the rate of barrier repair as they contain lipids similar to those found naturally in our skin. Jojoba Oil is an excellent example of an emollient. Occlusives help to form a barrier over the top of the skin increasing moisture levels and help prevent epidermal water loss. Avocado Oil has excellent occlusive properties.

    Avoid // Over exfoliating will strip away your skins protective barrier, choose gentle, pH balanced exfoliators that will help to protect your acid mantle.

    Apply // A Broad Spectrum UV Sunscreen daily

    Until next time..

    be human | be kind | be you







    1. Skin pH: From Basic Science to Basic Skin Care  - Saba M. AlI and Gil YoSIPoVITCH  Department of Dermatology, Wake Forest University Baptist Medical Center, Winston-Salem, USA
    2. The pH of the Skin Surface and Its Impact on the Barrier Function - Schmid-Wendtner M.-H.a · Korting H.C.b
    3. Jung, YC, Kim, EJ et al: Effect of skin pH for wrinkle formation on Asian: Korean, Vietnamese and Singaporean. J Eur Acad Dermatol Venereol: 27(3):e328-32, 2013.


    Thanks so much for sharing! I have cut out products containing alcohol and I have been more focused on nourishing my skin with oils because it just felt like the right thing for me, but I really had no idea why. Now I know! Thanks :)

    Rachel xx

    Rachel @inspirethewild July 07, 2017

    That is so good to know. Thanks for putting this together so succinctly.

    Chantal Vanderhaeghen July 01, 2017

    I’ve never even heard of this! Thanks so much for bringing it to my attention :’)

    Sarah June 30, 2017

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