When your beauty routine kills certain bacteria
The use of moisturizers and sunscreens is associated with changes in the skin microbiota that lives on the surface of your skin and contributes to its health.
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About this article
The skin is a vital barrier: it protects our bodies from the sun's harmful ultraviolet rays, various chemicals we come into contact with, and microorganisms we encounter. To help it perform this task, it hosts skin microbiota, a collection of microorganisms that play a key role in our immunity. But what effect do the moisturizers and sunscreens we regularly apply to this tiny world have?
To identify and understand the influence of these routines on our skin microbiota and skin health, a team of researchers studied the faces of 10 men and 27 women1.
Your beauty routine changes your microbiota
When it comes to skin, we all have things in common (such as hosting bacteria like Cutibacterium acnes and Staphylococcus epidermidis, according to the skin of the 37 participants in this study), and differences (a highly variable diversity of species living on our epidermis). Our facial skincare routine seems to have a significant impact on this tiny world: the relative abundance of skin microbiota species is higher in participants who only use moisturizer compared to those who use a combination of moisturizer and sunscreen. Certain bacterial species also seem to depend on skincare routines: if you double up on skin hydration with sunscreen, you are likely to promote bacteria such as Corynebacterium sanguinis and Brachybacterium nesterenkovii.
Some figures on skin diseases
- 4.69 billion cases of skin and subcutaneous tissue disorders, responsible for 41.9 million disability-adjusted life years, were recorded worldwide in 20212.
- Skin and subcutaneous diseases are forming one of the top 10 causes of disability2.
- Most of the skin diseases burden in any community is caused by about 10 common general skin diagnoses and that, with the essential medicines, the right training and support, local health teams could effectively care for these patients2.
- On February 10, 2025, skin diseases were declared a global public health priority by the World Health Organization (WHO)3.
Effect of sun exposure
Another factor that greatly influences this microscopic world on your skin is sun exposure, which is enough to alter the abundance of beneficial microorganisms, such as Malassezia restricta yeast or S. epidermidis bacteria. Do you enjoy sunbathing and regularly use moisturizer? Your lifestyle probably promotes the growth of protective species such as S. epidermidis, which keep pathogens such as S. aureus at bay. And when we talk about the sun, we inevitably think of hyperpigmentation: according to this study, the use of sunscreen appears to be unrelated to the bacteria associated with hyperpigmentation (Corynebacterium spp.). These results still need to be confirmed in larger cohorts.
One thing is certain: when you apply your moisturizer or sunscreen tomorrow, you will spare a thought for the tiny bacteria, fungi, and other viruses that discreetly coexist on the surface of your skin for your own good!
