Restore & maintain
good bacteria
on the skin

What is AO+ Mist?

AO+ Mist is a spray for the skin to be used after bathing, before bedtime and whenever you find convenient. The spray consists of strain of safe live-cultured AOB (Ammonia Oxidizing Bacteria). It is a “good bacteria” found in nature that live off the ammonia you produce through sweat on your skin.

What is “AOB” (Ammonia-Oxidizing-Bacteria)?

You clicked, so we're going to get scientific with you now. Ammonia-Oxidizing-Bacteria (AOB), also known as “Nitrifying Bacteria,” are microorganisms that consume ammonia for energy and are present wherever a nitrogen cycle is taking place. This means wherever you find ammonia (their energy source), this class of bacteria will be found. The only anomaly to this is human skin, which we think is a rather interesting example of the effects of modern lifestyle. AOB also do not rely on solar energy or carbon (instead, they grow by consuming inorganic nitrogen compounds). The specific type of AOB used in our AO+ Mist is Nitrosomonas eutropha D23.

Wait a second... Bacteria is GOOD?

Yes! This bacteria actually does good! Similarly to how probiotics are “good bacteria” for the stomach, this AOB do good for the skin. Now, we understand that the notion of a “harmless bacteria” might be a bit tough to wrap your head around, but follow us here for a minute: AOB are found everywhere in nature and have never been implicated in any human illness over the many decades that they have been researched. If you’ve ever walked barefoot on dirt, swam in a lake or the ocean, you probably emerged refreshed and covered with AOBs. Although our strain is cultured and produced to cosmetic grade quality it has the same safe properties as natural AOB. AO+ Mist is non-pathogenic - i.e. the live bacteria lack the genetic machinery needed to cause infection.

How does it work?

The Nitrosomonas in the AO+ Mist work by consuming the irritating compounds produced by your skin (like ammonia and urea in sweat), and in turn producing beneficial byproducts. Specifically, Nitrosomonas produce Nitrite and Nitric Oxide. Nitrite tames the bad bacteria and promotes the good bacteria on the skin. Nitric Oxide is a key antioxidant and anti-inflammatory. These two byproducts together do a great deal to help promote healthy skin overall.

How do I use it?

Good question! We're so glad you asked. First, shake the bottle. Then, spritz 5-7 times all over the body, twice a day. Be sure to focus on areas with high amounts of sweat glands: the face, scalp, underarms, groin, hands, and feet. Great times to spritz are: after showers, after swimming in a pool (rinse the chlorinated water off first!), before workouts, and in the evenings before bed. Most importantly - experiment! See what works best for you in terms of routine, frequency and quantity. Happy misting!

How do I recycle?

Click here for recycling information.

When do the products "go bad"?

Unlike most other products in your bathroom, you’ll notice all of our products have an expiration date. That’s because none of our products contain preservatives. Preservatives inherently prevent bacterial growth, so they are not compatible with the AOB in the Mist.

  • The Mist will keep its potency for 6 months in the fridge or 4 weeks at room temperature.
  • The Shampoo and Cleanser do not contain live bacteria, and are completely sterile until your first pump. Once you begin using your Shampoo and Cleanser, they will last for 8 weeks.
  • The Moisturizer does not contain live bacteria, and is completely sterile until your first pump. Once you begin using your Moisturizer, it will last 6 months from first pump.

Why do I need to refrigerate the AO Mist? What about the Shampoo, Cleanser, and Moisturizer

You should keep the AO+ Mist refrigerated until you first start using it. Once you start using the product, you can keep it at room temp, somewhere convenient like your bathroom counter, for example. After 4 weeks at room temperature, the bacteria start to lose activity. Think of the refrigerator as a way to pause or slow down the loss of activity. You’re welcome to keep the AO+ Mist in the fridge even after you begin using it in order to stretch the life of the product beyond 1 month.

Since the Shampoo, Cleanser, and Moisturizer do not contain live bacteria, they do not need to be refrigerated. The Shampoo, Cleanser, and Moisturizer are sterile until your first pump. Because we’ve formulated these products without preservatives, you should discard the Shampoo and Cleanser after 8 weeks of use, and Moisturizer after 6 months of use.

How do you protect the products during shipping? What if I live somewhere hot?

Don’t be concerned about the temperature upon arrival. Room temperature is not harmful to the AOBs in your bottle unless it is for extended periods of time (the 4 weeks on the label). It's really the temperature extremes that are harmful. This is why we ship expedited so that all packages arrive between 1-3 days from leaving our facility, depending on where in the US or Canada you live. We also use insulated mailers to further protect the AO+ Mist from getting too hot or cold (depending on the season), so it's not likely that anything inside the package ever reached dangerously high temps.

    So, are you saying soap is bad?

    Not at all! The AO+ Mist is not a replacement for soap. We just want to help society understand that there’s a difference between "clean" and "sterile". Our obsession with being as clean as possible has generally resulted in removing all bacteria from our skin, including the beneficial and necessary ecosystem that is our skin microbiome.

    Do I have to stop showering?

    Nope! (Phew!) AO+ Mist thrives in water and you can and should continue showering as you would normally. It’s not necessary that people stop showering or give up their soaps and shampoos. Our research shows that daily application along with normal showering in regular tap water produces a sustained level of AOB on skin. We recommend applying AO+ Mist daily as part of your usual personal hygiene routine.

    What about moisturizers?

    Many of our users find that once they get into a regular routine with the Mist that they no longer have the need for a moisturizer. If you do find that there are areas that need extra hydration, our biome-friendly Moisturizer is perfect for anywhere you need it. It can be used in conjunction with the Mist (since it is biome-friendly, it can be applied before or after Misting) or you can use it on its own.

    What about makeup?

    You can still wear makeup and still gain the benefits of AOBs. All makeup has preservatives, so this means as it sits on our skin all day, it won't be too friendly to the AOB in your mist (sigh...). One way to lessen the AOB damage is to apply your makeup, let it fully absorb, and then spritz the mist as the final step. If that's too tricky, you can try using just using the Mist after you've taken off your makeup in the evening and still gain the benefits while you sleep. It's important to note: putting on your makeup the next morning won’t "reverse" the beneficial effects of what was at work overnight.

    What about deodorant?

    Much like with makeup, deodorant is something you'll need to experiment with as you add AO+ Mist into your daily routine. The ingredients in most deodorants will be harmful to the AOB, but you may find that you are able to use less of it over time. If you want to try going cold turkey with deodorant use, remember that it may take some time to "smell" the positive results of your Mist working.

    What about my hair?

    For many, our shampoo softens and detangles enough that they don’t need to use conditioner, or that they need it less often. For others that’s not the case. Don't worry, there's no need to cut out conditioner cold turkey. If you use conditioner, make sure to keep it away from your roots, which is where the AOBs in your Mist like to live.

    What about sunscreen?

    We know SPF is very important especially if you spend a lot of time outdoors or if you are very conscientious about your level of sun exposure - and that's OK. The key thing is to remember to spritz your mist at times that you aren't wearing the sunscreen (like at night). The evening is actually the best time to mist because that is when the bacteria are most active! While we haven't tested many SPFs for their compatibility with AOB, it's likely that they aren't very compatible However, you can spritz your mist on other areas (like the underarms) to maintain the benefits during the day for areas that aren't as exposed.

    What about swimming?

    Swimming pools most likely kill AOB, while the ocean and fresh water sources should be just fine. If you do swim in a pool, you can replenish your AOB by rinsing off after a dip and misting with your AO+.

    Are the products safe to use during pregnancy or on children?

    The bacteria in the AO+ Mist is safe for use during pregnancy and for children of all ages. Our products are formulated to work in conjunction with the ammonia-oxidizing-bacteria (AOB), a fragile microorganism that grows very slowly and is killed by a single use of basic soap. This means that we must use ingredients that are incredibly mild and gentle.

    If you have any additional questions about safety, please feel free to contact us directly at

    I'm an over-achiever, how can I get the most of out my products?

    Hey! We're over-achievers, too! First off, AOBs thrive in the evening, so make sure to spray at night before bed. Another tip? Limit your use of conventional cleansers and soaps over time. We've found that even at low concentrates, these can be harmful to AOBs. You might be surprised at how little you need!

    Will I always have to use this stuff?

    This all depends on your personal habits - not just the showering and the products you use, but also the amount you sweat. It’s different for everyone, and we’re still working on defining what a "healthy biome" is. Having a healthy biome is a ongoing process, not simply a destination. We view a “biome-friendly” routine as a two-part process. First is replenishing the beneficial bacteria that we lose naturally on a regular basis (this is what our AO+ Mist does), and the second is making sure that the products we do come into contact with don’t hurt the beneficial bacteria of the skin. The good bacteria of our skin is constantly in flux based on our environment and what we expose it to. Microorganisms are constantly falling off, scrubbing off, and they definitely don't live forever. It's a natural part of the process. For this reason, it's important to replenish. AOB in the mist (and other good bacteria) don't just grow endlessly. Does this mean you'll always have to use the same amount of AO+ Mist? Not necessarily. Once again, it depends on your personal habits, environment, and routine. We encourage you to experiment and find what works best for you as time goes on.

    What about the science?

    We're so excited that you want to learn more about the skin biome and AOB's. Here's where you can learn more about the research side of AOB's:

    Can't I just make this myself at home?

    One of the most complex production pieces for us currently is producing 100% pure product. We test at every step of our process to make sure it only contains AOB and not other microorganisms. But let's say you didn't care about contamination and wanted to try to grow your own bacteria anyway. You'd still run into some issues with the final product. It turns out some microorganisms adversely affect the Nitrosomonas, and the concentration level of the AOBs is very important to determining the brew's potency and effectiveness.

    Do you test on animals?

    AO+ cosmetic products are never tested on animals. Because we believe in being fully honest and transparent, we want to make you aware that AO+ Cosmetics is a wholly owned division of AOBiome, LLC, a biopharmaceutical company engaged in high level bio-therapeutic research and testing. The FDA requires animal testing as part of their process to ensure that pharmaceuticals are both safe and effective and there is no way around this process. AOBiome is committed to work with the FDA to find alternatives to animal testing whenever possible and to minimize animal testing when no alternative is available. We recently became a contributing member of the ASCCT, a scientific society dedicated to the promotion of toxicology testing and research that reduces and replaces the use of animals.

    Will temperature extremes while shipping hurt my product?

    The short answer is no, temperature extremes experienced during shipping will not cause harm to your Mist. We’ve done extensive temperature and shipping testing to make sure the AOB in your Mist are in good condition when they arrive.

    All shipments are sent via 2-day express service. This minimizes time spent in temperature extremes, both hot and cold. Furthermore, during extremely hot (summer) or cold (winter) times of year, we employ special packaging for certain geographical areas so that you don’t have to worry.

    Lastly, it’s important to remember while the AOB in the mist do have temperature sensitivity, they are not as sensitive as you might think. They are happy and active across a large range of temperatures: between 32 degrees and 120 degrees fahrenheit. Below are some more specifics in case you’re curious!

    The Mist and heat
    The Mist can withstand 72 hours at 100 degrees fahrenheit. It would require hours at well-over 110 degrees to degrade the AOB.

    The Mist and cold
    Freezing temperatures are always bad! The coolest it should get is 32 degrees fahrenheit.

    Can these bacteria cause harm if ingested?

    No. These bacteria don't have the ability to contribute to colds or infections of any kind. They are non-pathogenic and various sequencings of our strain as well as many others confirm that they genetically do not contain the ability to take on pathogenic characteristics.

    Here is a simple overview as to the basic characteristics of the bacteria that make them incapable of causing harm:

    1. The bacteria only consume ammonia as their food. This is an important attribute because pathogenic bacteria typically consume things containing carbon.

    2. The bacteria cannot survive in your digestive tract or blood. Their food source is not there (ammonia from your sweat), and the pH is way to acidic in the gut for them to survive. They would almost surely die upon contact.

    3. The bacteria take 10-12 hours to double, which is a very long time (pathogenic bacteria typically take 20 minutes to double). This means that it would take a really long time for an "infection" to happen, and for there to be an "infection" they would need a lot of food (a lot of sweat). The amount of sweat you would need to produce in order to create an infection is something our bodies are not physically capable of.

    4. Lastly, you can kill the bacteria simply with soap. Which makes it a really easy thing to get rid of. Harmful bacteria take a whole lot more effort to get rid of.

    How can I contact you?

    Questions about the product? Want to tell us about your day? We're here for you! Email us at

    What does "biome-friendly" actually mean?

    In short, biome-friendly means that it will keep your skin microbiome intact, and will not harm AOB, or drastically alter your skin microbiome.

    Anything with a preservative will harm AOB, which is why Mother Dirt products are preservative-free. Most products contain preservatives to keep them shelf-stable for long periods of time. This is also why all Mother Dirt products have an expiration date.

    We use AOB as our core measurement for testing biome-friendliness. AOB are one of the most sensitive microorganisms on our skin. Because of this, we believe that testing against AOB is a great measurement for the overall impact on the skin biome. If an ingredient or product is friendly to AOB, then it will also be friendly to the other delicate microorganisms of the biome as well.

    All biome-friendly products come with a unique label, which verifies that it’s been tested, but also includes important information about the expiration date and the lot number for the product.

    Visit to learn more.

    How sensitive is the microbiome? Will one wash with soap remove my AOB?

    The truth is that our skin microbiome (like other microbiomes) is a sensitive ecosystem that is constantly evolving. External factors as mild as a hot water shower or as harsh as swimming in a chlorine pool will cause changes in our microbiome. The bacteria in Mother Dirt's AO+ Mist are very sensitive to conventional soap, which will remove them completely with gentle scrubbing. This is normal and expected. Remember that the body always wants to go back to equilibrium and puts the proper systems in place to do so. Therefore the skin microbiome will recover, especially with the help of a biome-friendly routine, which is why we created our biome-friendly Cleanser, Shampoo, and Moisturizer. The problems begin when we don’t allow our skin microbiome to recover and return to its natural state of equilibrium.

    I use essential oils / I make my own products, are they biome-friendly?

    Here’s a quick list of common products/ingredients and their biome-friendly status:

    • Provided they are pure oils, preservative-free, and added-fragrance free; vegetable or seed oils such as coconut, almond, and olive oils, along with Argan and Jojoba oils appear to be generally biome-friendly.
    • Thus far, we have tested and qualified rose oil, rose hydrosol, and ylang-ylang as being biome-friendly and compatible with AOB.

    Not biome-friendly:
    • Citrus oils such as lemon, orange, and grapefruit oils tend to be antibacterial and toxic to AOB so we recommend that you avoid citrus oils if you’d like to maintain a biome-friendly routine.
    • Many, if not most of essential oils, are antibacterial and antifungal to some degree. Short of testing each one, it is hard to generalize and predict whether the essential oils that you are using will be biome-friendly.

    When using products that are not biome-friendly, we highly recommend applying the Mist as the very last step in your skincare routine, after all other products have been absorbed.

    Are your products sulfate-free?

    We know that many people are concerned about sulfates in cosmetic products, and we’re happy to report that we do not formulate our products with sulfates. And in case you’re curious about the Sodium Laurylglucosides Hydroxypropylsulfonate you see listed in our shampoo ingredients, it’s not a sulfate; rather, it's a sulfonate. Sulfonated Alkyl Polyglucosides (SAPGs) have evolved over the past decade and have become an efficacious primary surfactant (the stuff that suds) alternative to sulfates.

    In fact, sulfonates tend to be among the most gentle surfactants. We prefer sulfonates because of their mildness to the skin and eyes, their foaming properties, and the renewability and environmentally-friendly nature of the materials.

    Do you use chemicals in your products?

    We get this question a lot, and we’re thrilled to! It’s great to see consumers taking an active role in the products they use. We’ll start by clarifying this question: Everything is a “chemical” including water. So the fear with “chemicals” is typically around the use of harsh or toxic chemicals. It is an important value of ours that we make products that don't pose harm to people or the environment. (Read our blog on our partnership with Campaign for Safe Cosmetics as well as the Green Chemistry and Commerce Council.)

    All of our ingredients are plant-derived, and any chemistry performed on them is green chemistry. We have taken special care throughout our entire supply chain to source raw materials that are sustainable and ethically produced. We have also performed impurity and safety tests to ensure, to the best degree we can, that our products safe and mild.

    None of these tests are required by regulatory bodies, but as mentioned above, this is an important value to us—it is important we go above and beyond.

    If you don’t use harsh chemicals, then what’s the deal with the long complicated names of your ingredients?

    Using the Latin names of our plant-derived ingredients, such as Caprylic/Capric Triglyceride (from coconut), is the required format by the FDA for cosmetic labeling. It’s called the International Nomenclature of Cosmetic Ingredients, or INCI for short. Part of it is rooted in Latin as a legacy from medicine, where Latin names are always used because because there are different types of species within the same genus of plant. The full Latin name ensures we are getting exactly the right plant, which in medicine is important due to safety.

    To completely comply with the International Nomenclature of Cosmetic Ingredients (INCI), in addition to listing the ingredients with the proper Latin name, we must also feature the different compounds of an herb or nutrient. This is all to say that long, unpronounceable words shouldn't necessarily be a cause for concern. What's in the parenthesis—a natural, nontoxic source—following that word is more significant.

    How is the AO+ Mist any better than other non-living / freeze-dried / live probiotics?

    Mother Dirt is the consumer products division of AOBiome, a health-sciences company studying the skin microbiome. The AOBiome team of scientists and researchers believe that there are real issues with many probiotic skincare products—whether living, freeze-dried, or non-living—and for a number of reasons, chief among these being quality control and assurance.

    All AOBiome products are packaged and filled in U.S. facilities that meet or exceed the FDA’s proposed Cosmetic GMPs, and every facility that packages AOBiome products is registered with the FDA. Additionally, each batch of AOBiome product undergoes strict quality control testing before being released for sale.

    To ensure that our probiotic, the AO+ Mist, arrives at full activity, we ship it in temperature-protective packaging, which varies as needed based on weather and time of year. The Mist also comes with clear labeling to refrigerate upon arrival (to extend the maximum efficacy to 6+ months). It is fine without refrigeration as long as it doesn't get exceptionally hot or freeze within 30 days after receipt.

    That's all to say that we take great care with the production, packaging, and shipping of our Mist, and we don't know that other products that are not as carefully sourced and shipped can offer the same benefits.

    How does the bacteria in the Mist differ from the bacteria in yogurt? (Or probiotic supplements in general.)

    While their general function is the same, the types of bacteria used are very different. This is because there are many different kinds of bacteria and each thrive in different environments. The environment of the gut is very different from the environment of the skin.

    Probiotics in the form of yogurt or supplements target the gut biome. These types of bacteria need to be able to withstand more acidic environments. Though these products also aim to shift the balance of good and bad bacteria, they would not be suitable for the skin, and vice-versa.

    The AO+ Mist uses a bacteria suited for the skin: Nitrosomonas - a family of bacteria that consume ammonia found in our sweat, in turn producing beneficial byproducts that lead to healthier looking skin.

    What about traveling with Mother Dirt?

    All of our products are no more than 3.4 fluid ounces and TSA-approved for carry-on. We always recommend keeping the Mist in your carry-on bag to ensure that the live AOB (Ammonia-Oxidizing Bacteria) are not exposed to the extreme temperatures of the checked-bag cargo hold.

    Don't worry about x-ray machines. The AOB have a very small genome, so they make a very small target for the x-rays. Diagnostic doses of x-rays have no discernible effects on bacteria or their environment.

    The Shampoo, Cleanser, and Moisturizer can go in your checked bag. If they freeze and then thaw, they are still okay to use.

    Again, extreme temperatures will affect the little guys in the Mist, so better to play it safe and bring them aboard. To be super specific, the Mist can withstand 72 hours at 100 degrees fahrenheit. It would require hours at well-over 110 degrees to degrade the AOB. Freezing temperatures are always bad!

    How to estimate the shipping status for your AO+ Mist

    The AO+ Mist ships on the first MONDAY or TUESDAY following your order date. You'll receive it that same week if you order before NOON on TUESDAY. Shampoo and Cleanser ship within 24 - 48 hours of order. (Want it sooner? Use Rush Shipping.)

    We ship Fedex or UPS from Boston, MA: When your product ships you'll receive an email confirmation with tracking info from

    Important info for International Orders: Occasionally, customs may require a brokerage fee and/or additional taxes, and we are sorry that we cannot cover additional import duties associated with receiving our products at this time. We do our best to forestall this prior to shipment in package labeling and declaration. International orders are shipped on Monday of each week.

    Important info for Rush Shipment Orders: Order by 2pm Monday - Friday, and receive your shipment in 2 business days. Orders received after 2pm and on weekends are shipped the following business day. US only.