Caring for your skin microbiome in summer

With the return of sunny days, many of us are eager to enjoy the outdoors and soak up the sun! However, it’s essential not to overlook our skin’s health. Understanding the skin’s role and composition is key to adopting the right habits and routines to care for it properly and effectively.

Our skin is our first line of defense against external aggressors. It is composed of a lesser-known protective layer: the skin microbiome.

The biofilm is a thin layer of microorganisms—primarily bacteria—that adheres to all surfaces. In humans, it is found notably on the skin and interacts directly with the skin microbiome. When under attack, the bacteria organized in the biofilm form a united community, responding much like a Roman army to defend the body.

As a true protective shield for our skin, it is essential to preserve the biofilm and avoid damaging it.

First and foremost, it’s important to limit external aggressors that disrupt the structure and composition of the skin microbiome — one of the main ones being the sun. UV rays affect the growth and activity of the microorganisms that make up the biofilm. Wearing sunscreen daily is essential to prevent UV rays from damaging our skin barrier. These rays can either promote the overgrowth of certain microorganisms or reduce the overall diversity of the skin microbiome. Such imbalances can lead to skin issues like irritation or inflammation.

The skin microbiome also plays a key role in maintaining the skin’s immune barrier. When disrupted by sun exposure, the skin’s protective function can be weakened, increasing the risk of inflammatory reactions such as sunburn. This imbalance can even lead to irreversible cellular damage, including dark spots caused by the overproduction of melanin.

That’s why applying a broad-spectrum sunscreen (UVA + UVB), daily and suited to your skin type, is crucial to protect your skin barrier from UV-related damage.

Secondly, to avoid imbalances and maintain healthy-looking skin, it is essential to use skincare products that are respectful of the skin microbiome. The key lies in maintaining the balance of the biofilm — and therefore of the bacteria it hosts.

However, certain cosmetic ingredients can disrupt this balance by negatively impacting the skin’s bacterial flora, which may lead to skin issues or an unsatisfactory appearance. That’s why it’s important to ensure that your skincare products are microbiome-friendly.

In practice, this means choosing gentle, non-irritating products and avoiding harsh cleansers (like aggressive exfoliants). Opting for ingredients such as prebiotics and probiotics supports the growth of beneficial bacteria and helps reinforce the skin barrier. Soothing ingredients, like aloe vera, can also help protect the skin from sun-induced irritation.

Finally, well-hydrated skin is more resilient to external aggressors. Staying well hydrated — both by drinking water and using proper moisturizing care — remains essential.

With this in mind, our experts at BYOME LABS — a specialized analysis laboratory focused on the microbiome and biofilm — are dedicated to testing the impact of cosmetic products on the skin flora.

Their work aims to:

• Understand the composition of the skin microbiome

• Analyze how it functions

• Highlight the importance of the skin barrier for overall skin health

• Study and measure the impact of cosmetic products on the biofilm

• And much more!