What Can an At-Home Skin Microbiome Test Tell You?

What Can an At-Home Skin Microbiome Test Tell You?

One of the trendiest topics in skincare right now is the skin microbiome—the millions of tiny microbes, including bacteria, fungi, and viruses, that live on and in our skin. In the past 10 years or so, research on the skin microbiome has exploded, revealing many new and exciting discoveries that have highlighted how important the skin microbiome is for the health of our skin. As a result of these findings, interest in microbiome-friendly skincare has grown, with many top and up-and-coming  brands releasing products that claim to protect, nourish, or balance the skin microbiome. 

At Ellis Day Skin Science, we also think a lot about the skin microbiome and, in fact, our innovative skincare products are grounded in cutting-edge microbiome science. Our hero ingredient is a proprietary blend of bacteriophages (aka phages) that target and kill blemish- and inflammation-causing Cutibacterium acnes (C. acnes for short) bacteria on skin. These phages, which can be found in our Balancing Phage Serum, our Hydrating Phage Serum, and in our new Chill Face Spray, are native members of a healthy skin microbiome, where they function to eradicate bad bacteria and help the good bacteria to thrive. Beyond phages, our products are loaded with other gentle, microbiome-friendly, skin-native ingredients, such as hyaluronic acid, which help to promote the health and well-being of your skin, without disrupting its natural microbial ecosystem.

So, all this is to say that the Ellis Day team is a big fan of things aimed at understanding and maintaining your healthy skin microbiome!  One recent trend in microbiome-focused skincare has given us pause: companies selling at-home skin microbiome testing kits, which allow customers to identify the microbes that make up their own skin microbiome. These skin microbiome test kits generally involve using a sterile swab (like a Q-tip) to collect a DNA sample from the surface of your skin by simply rubbing the swab over your skin a few times. Then the sample is sent to a lab for DNA sequencing analysis to determine which microbes are present. Such skin microbiome test kits are just beginning to hit the market, although similar products for measuring and analyzing the gut microbiome have been available for a few years. 

While this sounds exciting (and as a microbiologist, I’m certainly curious about what microbial species are living on my skin!), there are several reasons for caution. For one, the skin microbiome is very complex. This microbial community contains up to 1000 different species and differs drastically depending on the location on your body: the skin microbiome on the back or forearm is very different from the facial skin microbiome. Second, although a lot of research has focused on characterizing the ‘healthy’ skin microbiome, there is no clear consensus on what constitutes the ideal microbiome or which products are best suited for a particular microbiome “type.” 

Third, even when we know which skin bacteria are associated with certain skin conditions, it’s not always possible to identify these from an at-home skin microbiome test kit. This is because, in the case of C. acnes for example, not all C. acnes strains are problematiconly certain ones. And skin microbiome test kits may use DNA sequencing technology that doesn’t have the precision to identify particular strains associated with skin conditions or diseases. So, if you find out you have a lot of C. acnes on your skin, it could be indicative of a problem, or it could be totally fine (meaning you have lots of the good strains of C. acnes!), leaving you with more questions than answers. 

Let’s Be ClearTM: at Ellis Day, we think that everyone should be empowered to learn about the science of their skin, and to have the information they need to choose the safest and most effective skincare products. We also know that one of the most important aspects of science is understanding its limitations. Studies on the skin microbiome have provided us with a window into the complex and fascinating world of microbes that live on our skin, but we still have a lot to learn. So while it may be kind of cool to see the different microbes that make up your own skin microbiome, we are definitely not at the stage where we can make specific skincare recommendations or diagnose particular skin conditions based on these data.  So, keep that in mind before you shell out lots of money on an at-home skin microbiome test kit.

If you have any questions about the skin microbiome, Ellis Day Skin Science, or how our skin-native active ingredients can help to promote a healthy skin microbiome, please email us at hello@ellisdayskinscience.com. We’re happy to help!


  1. Barnard E, Shi B, Kang D, Craft N, Li H. The balance of metagenomic elements shapes the skin microbiome in acne and health. Sci Rep. 2016;6:39491.
  2. Fitz-Gibbon S, Tomida S, Chiu BH, et al. Propionibacterium acnes strain populations in the human skin microbiome associated with acne. J Invest Dermatol. 2013;133(9):2152-2160.
  3. Grice EA, Kong HH, Conlan S, et al. Topographical and temporal diversity of the human skin microbiome. Science. 2009;324(5931):1190-1192. 
  4. Grice EA, Segre JA. The skin microbiome. Nat Rev Microbiol. 2011;9(4):244-253. 
  5. Marinelli LJ, Fitz-Gibbon S, Hayes C, et al. Propionibacterium acnes bacteriophages display limited genetic diversity and broad killing activity against bacterial skin isolates. mBio. 2012;3(5):e00279-12.
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Dr. Laura Marinelli is a skincare-obsessed scientist who has spent her entire academic career researching phages and the microbes that live on our skin and make up our skin microbiome. She earned her PhD at the University of Pittsburgh, completed her postdoctoral training at UCLA, and is now living her longtime dream of creating phage-based skincare products to improve skin health with Ellis Day Skin Science. Laura has been a part of the Ellis Day team since 2017 and currently lives in Baltimore, Maryland with her husband, three kids, and two cats. 

About Ellis Day Skin Science

We believe that modern skincare must be grounded in true microbiome science and that the most potent, safe, and effective active ingredients are those that are native to healthy skin. 

At Ellis Day Skin Science, we formulate pioneering skincare products using skin-native active ingredients, for the cleanest, safest and most natural approach to healthy skin. These include bacteriophages that eliminate bacteria associated with breakouts, inflammation, and irritation, and enable good bacteria to flourish. 

We use cutting-edge science to leverage these powerful active ingredients, creating products that are just as kind and conscientious as they are effective, so that everyone can feel empowered with balanced, clear, radiant, and resilient skin.

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