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What is the skin microbiome?

What do we know about our surface microbiome and how this impacts our skin and skincare routine?

The skin microbiome is a relatively new area of research, and one that is continually evolving. Despite there being so much still to discover, what we do know already is that it is incredibly important for overall skin health. Here we explore what we know about the skin microbiome and how we can use skincare to best support it. 

What is the microbiome of the skin?

Being the largest organ of our bodies, the skin acts as a barrier to protect us from the outside world, and is our first line of defence against pathogens, UV light and damaging free radicals. 

The surface of the skin is inhabited by a colony of microorganisms, mainly bacteria, fungi and viruses, all contributing to what is known as the microbiome. This is similar to that of the gut and is essentially the ecosystem of our skin that regulates its immune ability and protects against invasion by harmful organisms. 

The exact makeup of your microbiome will depend on both internal and external factors and will differ from person to person. From our internal physiology (age, gender) to the climate we live in, all contribute to the functioning of a healthy microbiota. 

Why is the skin microbiome important?

The microbiome of the skin is extremely important for many reasons. Firstly, it maintains our skin’s natural pH of 5.5, which is slightly acidic to inhibit the growth of any harmful microorganisms, whilst creating a healthy environment for our good bacteria, which helps to protect against infection. It is important to have a balanced and diverse microbiome, as disruptions to its harmony can result in skin conditions such as acne, eczema or psoriasis. 

How can the skin microbiome become imbalanced and what happens when it does?

Over the last century or so, changes in lifestyle have contributed to disruption of the microbiome. From washing in hot water on a daily basis to using harsh surfactant-based products; these hygiene habits we have adopted are putting extra stress on the skin. 

As a consequence of continually stripping the skin of its natural lipids alongside elements of the microbiome, a reduction of the barrier function of the skin can occur. This results in increased water loss and in turn increased dryness, sensitivity and redness. 

There has been recent evidence to suggest that imbalances in the microbiome can lead to or affect eczema. One study investigated the skin of patients with atopic dermatitis (eczema) during and after a flare up (when symptoms are worsened). Researchers noted a drop in the diversity of bacteria constituting the microbiome in these patients during their flare up as opposed to before (Byrd et al., 2017). 

Which skincare products can support a healthy microbiome?

The primary way to support a healthy microbiome is simple; be gentle with your skin. Hygiene is important however be careful not to over-cleanse or scrub your skin. Chemical exfoliators such as AHAs and BHAs offer a more gentle resurfacing action than physical scrubs, and how often you exfoliate your skin should be based on your skin type.

It is also important to use products that support the acidic pH of your skin, for example a classic soap is generally alkaline (high pH) and hence will disrupt your acid mantle (low pH), and in turn your microbiome. 

With more research being done on the microbiome, certain products have been released onto the market that are formulated to contain particular strains of ‘probiotics’ that claim to support a healthy microbiome. This proves particularly challenging for formulators, as legally products must be preserved sufficiently to protect the user, so contain no living bacteria or ability to grow bacteria. 

More commonly used in skincare are prebiotic ingredients, such as yeasts, which support the growth of beneficial bacteria to help support microbiome diversity. However, the effects of these are still in early research, and the principle way we’d recommend to keep our microbiome healthy is by preventing its disruption with gentle, pH balanced products which contain barrier-supporting ingredients. 

Laila Manshi
Laila Manshi
MSc Cosmetic scientist