Commonly considered as the "bacteria causing acne," acne bacteria seem to have a negative reputation, as many people think of them to be "harmful to the skin." However, their presence is in fact closely related to the skin's moisture.
Let's discuss the role of acne bacteria.
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The Savior of Dry Skin: Acne Bacteria
An increase in acne bacteria leads to acne.
While this is certainly true, did you know that acne bacteria have other functions as well?
And, the workings of acne bacteria might actually help those struggling with dry skin issues.
Commensal skin bacteria thrive on substances like sebum and sweat.
Bacteria residing in our bodies typically feed on and produce other substances. For example, probiotic substances considered "good for the stomach" increase by microbiota feeding on nutrients from the food you eat, creating substances beneficial to the body known as "lactic acid bacterial products."
This is why they are called beneficial bacteria. And, same goes for acne bacteria.
While acne bacteria are commonly perceived as troublesome and a cause of acne, they aren't inherently harmful bacteria. Fundamentally, acne bacteria produce metabolic products such as propionic acid and fatty acids, contributing to the skin's barrier function.
While an excessive increase in acne bacteria due to sebum blockage can lead to acne, they generally function as good bacteria, providing moisture to the skin and protecting it from irritation and dryness.
The abundance of acne bacteria on the skin is not unusual. Unless it is extremely excessive, having acne bacteria on the skin is considered quite natural.
Acne Bacteria = Not All Bad
In general, unless there is excessive sebum secretion, acne bacteria do not cause acne. In fact, as people reach their 30s, most individuals experience a decrease in acne bacteria, making it a valuable bacteria for protecting the skin from dryness.
Acne bacteria are more prevalent in younger skin and tend to decrease with age. In one's teenage years, they are abundant on everyone's epidermis, but as one ages, the numbers diminish. If the bacteria become too scarce, dry skin may develop.
They also play a role in maintaining the skin to be slightly acidic, preventing harmful bacteria from settling on the skin. Acne bacteria, once considered an arch-enemy for those prone to acne, might now be understood as essential bacteria that maintain moisture and contribute to the skin's barrier function.
Skincare ingredients that increase acne bacteria
As acne bacteria decrease with age, it becomes important to maintain a healthy balance with thorough skincare. Among the cosmetic ingredients, "glycerin" and "high oleic acid oils" are believed to be easily consumed by acne bacteria. Let's introduce the background of each.
1. Glycerin:
Glycerin has excellent moisture-absorbing properties, enhancing skin moisture. It is a common ingredient used in moisturizing items like toners and creams, and products without glycerin are relatively rare.
Acne bacteria are known to favor glycerin and use it as a food source. According to research from a pharmaceutical company, providing glycerin to acne bacteria significantly increased their growth. (※1)
2. High Oleic Acid Oils:
Oleic acid is highly compatible with the skin and is a component close to "sebum." In fact, oleic acid is present in the fatty acids of our sebum. Acne bacteria generally prefer such fatty acids, making them more abundant in environments with a higher sebum content.
Oils containing oleic acid are often used as moisturizers, preserving skin moisture and offering anti-aging and dryness prevention benefits. "Argan oil," rich in oleic acid, is recommended for those concerned about dryness.
Debunking myths: "Does Olive Oil Cause Acne?"
Rather than the oil itself causing acne, it is more accurate to say that acne bacteria prefer oleic acid, one of the fatty acids it contains.
While it is not certain whether high oleic acid oils directly increase acne, it is advised to avoid elements that may contribute to an increase in acne bacteria. This is likely the intended meaning behind the statement that oils rich in oleic acid are not suitable for acne-prone skin.
Given that acne bacteria generally favor fatty acids, individuals with acne-prone skin might find jojoba oil, which has lower fatty acid content, a safer option when using oils.
Conclusion
Dryness is a common concern for many. Understanding that skin barrier and the activities of acne bacteria contribute to this issue, we can balance them to protect the skin from dryness and achieve clearer skin.
Instead of eliminating acne bacteria from the skin, maintaining balance can help create beautiful skin. To achieve never-ending moisture for your skin, consider consciously caring for these bacteria in your skincare routine.
This blog post was medically reviewed by Yutaka Shimokawa.