Beneath the surface of our skin is a thriving ecosystem of bacteria, fungi, and other microorganisms. This microbiome plays an important role that keeps our skin youthful, resilient, and protects us from harmful pathogens. Studies also show that a well-balanced microbiome can promote wound healing, defend against infections, and even counteract the damaging effects of UV rays. There has been a growing awareness of the skin microbiome and so many skincare companies are now introducing 'probiotics' for skin.How Effective Are These?The idea of using bacteria to improve skin health is not new. It has been there from as early as 1992, when scientists experimented with applying bacteria to treat acne and seborrhea, which is a skin condition that causes itching and flaking. The skincare industry today offers a wide range of probiotic-infused products, from cleansers and serums to moisturizers. All of them promise to rebalance the skin microbiome. However, a closer look also reveals that many of these products do not actually contain live bacteria. Instead they rely on prebiotics, which are the nutrients that encourage the growth of beneficial bacteria, or postbiotics, which are the byproducts of bacteria that may benefit the skin. The Challenge of Keeping Bacteria AliveWhy don’t most skincare products contain live probiotics? The answer lies in the difficulty of keeping bacteria alive throughout the manufacturing and storage process. Even if live bacteria make it into a product, there’s no guarantee they will survive long enough to take effect on the skin, where they must compete with millions of existing microbes.Can Live Bacteria Treat Skin Conditions?Despite the challenges, some researchers are testing whether live bacteria can treat specific skin conditions like eczema and acne. One promising approach focuses on the relationship between Staphylococcus aureus—a bacterium commonly found on the skin of eczema patients—and beneficial bacteria like Staphylococcus hominis, which can naturally fight off harmful microbes.A 2021 clinical trial tested a cream containing live S. hominis on eczema patients. After one week, participants saw reduced S. aureus colonization and improvements in redness and itching. A larger phase two trial is now underway to evaluate long-term effectiveness.Similarly, in a 2018 study, scientists performed microbiome transplants on eczema patients using Roseomonas mucosa bacteria from healthy skin. After 16 weeks, symptoms improved by over 50%.Can Probiotics Prevent Skin Aging and Cancer?Beyond treating skin conditions, probiotics may have broader benefits. In animal studies, a strain of Staphylococcus epidermidis was found to produce a compound that protects against UV-induced skin cancer. While human trials are needed, these findings suggest that probiotics could one day play a role in skin cancer prevention.Some studies also suggest that prebiotics and postbiotics may improve overall skin health. Ingredients like inulin, found in some skincare products, create a favorable environment for beneficial microbes. Additionally, bacteria found in fermented dairy products may help boost ceramide production, which strengthens the skin barrier and improves hydration.