Acne and the Skin Microbiome: Watch Out for the Rebound Effect!

In summer, the sun is shining and your skin looks glowing — it might even seem like your acne has magically disappeared…
Unfortunately, it’s just an illusion! Come fall, breakouts often return with a vengeance — this is known as the rebound effect.

Where does this phenomenon come from?
And more importantly, how can you avoid it while protecting your skin microbiome?

Acne, an inflammatory skin condition affecting over 6 million people in France, is often triggered by an overproduction of sebum. This excess sebum clogs pores, creating the perfect environment for the proliferation of bacteria responsible for breakouts and inflammation.
Beyond its physical effects, acne also has a significant psychosocial impact. A common source of discomfort and frustration, it may seem to miraculously fade with the first rays of sunshine — but that’s far from the truth.

While the sun can temporarily reduce blemishes due to its anti-inflammatory effects, it also dries out the skin, prompting it to produce more sebum to compensate for the loss of moisture.
This imbalance — combined with heat and sweating — encourages bacterial growth and often leads to a surge in acne breakouts after sun exposure.

Research has highlighted the essential role of the skin flora (also known as the skin microbiome) in maintaining skin health.
Composed of microorganisms living on the surface of the epidermis, the microbiome plays a key role in protecting against infections and maintaining the balance of the skin barrier.
Excessive sun exposure, along with the improper use of certain cosmetic products, can disrupt this delicate balance and create an environment conducive to the proliferation of acne-associated bacteria such as C. acnes, thereby worsening skin concerns.

This is where BYOME LABS comes in — a French biotech laboratory specializing in the analysis of the skin microbiome and biofilms.
Our expertise lies in studying the impact of cosmetic products on the skin flora, and in supporting brands in the development of innovative solutions to preserve this delicate balance.

BYOME LABS is also behind the creation of the “Microbiome Friendly” certification, offering consumers the guarantee that the products they use are truly respectful of their skin microbiome.

To minimize the damage caused by interactions between the sun, the skin microbiome, and acne-related bacteria, it’s essential to adapt your skincare routine:

• Cleanse your face daily with gentle cleansers to remove impurities without irritating the skin or further disrupting the microbiome.

• Hydrate your skin according to its needs to prevent dryness. Be careful to avoid photosensitizing ingredients, which can make the skin more vulnerable to sun damage!

• Use exfoliating products to unclog pores and remove dead skin cells. To protect the skin flora, opt for chemical exfoliants (fruit acids, AHAs, BHAs, PHAs…) and use them in moderation.

• Protect your skin from the sun with a high-level sunscreen to prevent damage from both UVA and UVB rays — and do so all year round!

Preventing the rebound effect of acne isn’t just about using the right products during or after sun exposure.
It’s also about caring for your skin year-round with products tailored to your skin type, avoiding overly aggressive formulas that can disrupt the microbiome, and adopting a consistent skincare routine.

By helping cosmetic brands scientifically demonstrate how their products affect the skin microbiome, BYOME LABS is paving the way for protecting and preserving our skin’s natural balance — allowing us to fully enjoy the pleasures of summer with peace of mind.