Bacteria is officially that girl.

Let's be clear: I'm talking about the kind of bacteria that make up your body’s ecosystems of microbes, called microbiomes. On the surface of your skin in particular, they’ve proven essential for its overall function; they help regulate inflammation, fortify the skin barrier, and even support immunity. In other words, your skin microbiome—and the bacteria it’s composed of—is kind of a big deal.

Now, skin microbiome tests are suddenly buzzy. The tests claim to get up-close-and-personal and give you intel. And that, in turn, might be able to tell you where your skin needs TLC. But are they legit? With that big Q in mind, I tapped experts to give you the lowdown on on these tests, and what they can—and cannot —tell you about your skin microbiome.

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Meet the experts: Jennifer Chwalek, MD, is a dermatologist at Union Square Laser Dermatology in New York City. Carmen Castilla, MD, is a dermatologist at New York Dermatology Group in New York City.

What is the skin microbiome?

When it’s functioning properly, the skin microbiome helps maintain a balanced skin pH, hydration, and protection against environmental aggressors (like pollution) and external irritants (like potentially harmful microbes).

The exact makeup of the skin microbiome differs for everyone. Jennifer Chwalek, MD, a dermatologist at Union Square Laser Dermatology in New York City, likens it to your fingerprint.

And there’s a lot that goes into keeping your unique skin microbiome working like a well-oiled machine, such as genetics, your climate, your environment, and even your lifestyle. If one of these factors gets thrown off—say, you’ve over-exfoliated to the point of damaging your skin barrier, or your beneficial microbiota are outnumbered by harmful ones, “it can cause inflammation and various skin disorders like acne or eczema,” says Dr. Chwalek. Even age can play a role, with your microbiome changing over time.

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It makes sense, then, that you might want to know everything about it so you can best take care of it.

Skin microbiome testing is on the rise.

Enter the tests designed to measure and analyze your skin microbiome. The concept isn't a totally novel one. "In the past, culture-based methods were mostly used to evaluate the skin microbiome—for example, a swab of the skin is taken, plated onto media, and then grown out in a culture," says Dr. Chwalek, who notes that this was largely done for research purposes and not to actually treat patients IRL. This is time-consuming and not very accurate, since some organisms might grow better than others in this condition.

But now, microbiome testing has gotten a DIY-friendly makeover with two at-home methods: Swab-testing and tape stripping. The swab method is as straightforward as it sounds: You swab your face and place it in a container for collection. With the latter, "the individual applies sterilized tape strips to the designated area of skin to be tested, usually for one minute—depending on the test," says Dr. Chwalek. Then, the strips are removed and placed into a container for analysis.

Theoretically, you’ll get your results and learn how best to treat your individual skin microbiome, ensuring happy, healthy skin—right? Not exactly.

At-home skin microbiome tests aren't perfect.

While there have been recent advances in sequencing methods, says Dr. Chwalek the technology is still far from straightforward or infallible.

First, these tests may not be accurate. “With swabbing, the pressure, direction and the number of times an area is swabbed are important variables that can impact the results,” says Carmen Castilla, MD, a dermatologist at New York Dermatology Group in New York City.

Tape stripping is generally more uniform and less prone to user error, she says, but, “the adhesive of the tape plays a critical role in bacterial collection, with some adhesives potentially having better efficacy,” she says. “Additionally, the tape adhesive may not perform as well on wet or oily skin.”

Plus, the area of the skin you test can impact results. That's because the microbiome is so finicky. Its composition can vary across skin’s surface, sebaceous glands, and hair follicles. “Each area has a different microenvironment, with its own unique microbiome profile,” says Dr. Castilla. “Using a tape or swab that only samples from the skin surface may not get a complete view of the microbiome present.”

And even if you do get accurate results, that doesn’t mean you can just adjust your skincare routine accordingly. While research has shown how changes in the microbiome can contribute to conditions like acne, eczema, and psoriasis, “we do not have great data on how to specifically treat these alterations,” says Dr. Castilla. For instance, we don’t even know for certain whether the changes in the microbiome cause or result from these conditions.

And keep in mind that the over-the-counter products typically recommended to “remedy” your skin microbiome aren’t overseen by any kind of governing body, meaning that “there is no standardization in what they are looking at or how they are extracting their information,” says Dr. Castilla. “Most of these testing kits are linked to products that reportedly will fix or work well with the ‘issues’ that may arise with your microbiome results, but there is no study showing that any of those products are effective at positively altering the microbiome.”

Ultimately, “there is great potential for these tests to be useful—however, we need strong research on how to determine what is an ideal microbiome, and how to effectively correct a skin microbiome imbalance,” Dr. Castilla says.

Translation: Researchers are still working out a baseline of what a “healthy” skin microbiome looks like in the first place, which makes it virtually impossible to confidently determine the best TLC for it. Without that, you're just looking at a bunch of data. Which, incidentally, seems to be the biggest upside of these tests.

For now, you probably don't need to take a skin microbiome test.

Once accurate tests, science-backed interpretation methods, and effective treatment options become available, then they can be put to good use by the general public.

Right now, the biggest benefit of at-home skin microbiome testing is in the amount of data that can be aggregated as more and more people spring for these tests. As more data gets collected, “it will aid in further research, which may result in changes in how we manage and treat various skin conditions,” says Dr. Chwalek. For instance, monitoring your skin microbiome could potentially predict flares of some conditions and allow you to take preventative measures.

But that's still a long ways away. Ultimately, Dr. Chwalek says, “most microbiome testing still raises more questions than it answers.”

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Deanna Pai

Deanna Pai is a freelance beauty writer and editor currently based in New York. She has more than 10 years of experience writing about beauty and wellness.