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While research suggests there are health benefits, the FDA doesn’t monitor or regulate the purity or quality of essential oils. It’s important to talk with a healthcare professional before you begin using essential oils and be sure to research the quality of a brand’s products. Always do a patch test before trying a new essential oil.

There are many different essential oil companies in business, including doTERRA. According to the company’s website, the name doTERRA is derived from the Latin words for “gift of the Earth.”

doTERRA claims to stand apart from other essential oil companies with sustainable oil sourcing practices and its Certified Pure Therapeutic Grade (CPTG) label showing the purity of its oils.

According to a National Association for Holistic Aromatherapy blog post, “CPTG” is a marketing term only, and the field is largely unregulated.

One of doTERRA’s most popular oil blends is called On Guard.

On Guard is advertised as a “protective blend” that can be used to support the immune system. It contains a blend of five essential oils, including:

  • wild orange peel (Citrus sinensis)
  • clove bud (Eugenia caryophyllata)
  • cinnamon bark/leaf (Cinnamomum zeylanicum)
  • eucalyptus leaf (Eucalyptus globulus)
  • rosemary leaf/flower (Rosmarinus officinalis)

According to doTERRA, On Guard can support healthy immune and cardiovascular function.

The company also claims that On Guard promotes healthy circulation when ingested and gives off an energizing scent when diffused.

In addition, you can use the oil blend as a natural household surface cleaner.

Although studies suggest some benefits to using On Guard, research is limited and not conclusive.

A 2017 study, which was funded by doTERRA and conducted by doTERRA employees, found that On Guard reduced inflammatory markers in human cells.

It also indicated that the oil blend may promote wound healing and immune function.

According to a 2010 study, the On Guard blend may be effective in helping treat and control the influenza (flu) virus.

The study found that the oil weakened the flu virus in in vitro canine kidney cells that were infected. These cells, called MDCK cells, are commonly used in flu research because of their susceptibility to the virus.

They also discovered that the oil may prevent this virus from producing as many viral proteins and being able to replicate as strongly.

Studies of the individual essential oils in the On Guard blend also suggest some benefits. A research review from 2019 indicated that eucalyptus essential oil may have immune-enhancing effects.

A 2016 study found that cinnamon bark essential oil vapor had antimicrobial effects against viruses and bacteria common in respiratory infections. Clove and eucalyptus oils were also effective, but in liquid form.

More research is needed on the various uses and combinations of essential oils, particularly in humans.

According to doTERRA, there are four primary ways to use the On Guard blend:

  • ingesting it
  • diffusing it into the air for aromatherapy purposes
  • applying it on the skin
  • using it on surfaces as a household cleaner

To ingest On Guard, doTERRA recommends putting three to four drops into a veggie capsule or soaking apple slices in water with two to three drops of the oil.

Per the company’s instructions, add one drop of oil to every 4 fluid ounces of water to dilute it.

The National Association for Holistic Aromatherapy advises against ingesting essential oils without consulting a medical professional.

To diffuse On Guard, you can add three or four drops into your diffuser’s liquid base. The oil will then diffuse into the air.

When applying the essential oils to your skin, be sure to dilute one to two drops of the oil blend in a base, such as coconut oil.

The first time you use it, check for any skin sensitivity by putting diluted On Guard on a small area of skin for a patch test. Use a 1:30 dilution ratio — one drop of On Guard to 30 drops of a base oil — for the test.

If you notice any irritation or inflammation, wash the area and discontinue use. If you don’t experience any discomfort after 24 hours, it’s likely fine to apply to a larger area.

To use the oil blend as a cleaner, add the desired amount of oil to water, and spray the mixture on surfaces.

On Guard may lead to skin sensitivity. Avoid direct sunlight or UV rays for up to 12 hours after using the product on your skin.

Applying undiluted essential oils can cause skin irritation or an allergic reaction. Be sure to dilute the On Guard blend, then test the mixture on a small patch of skin before applying it to broader areas.

Avoid using On Guard on any sensitive areas on the body, such as the eyes, inside of the ears, genital areas, irritated skin, or rashes.

Breathing in the oil may carry risks. A 2017 study found that inhaling eucalyptus oil, one of the ingredients in the On Guard blend, may be linked to seizures in some people.

Each person in the study was using eucalyptus oil for the first time, and more research is needed on its effects in the general population.

Ingesting certain essential oils or a large amount of oil may also be dangerous, particularly for children.

According to a 2019 case report, eucalyptus oil poisoning is more common in children than adults. Still, consuming eucalyptus oil may have caused seizures in two adult men in the report.

A 2018 case report additionally indicated that swallowing clove oil led to liver damage in a 3-year-old boy.

Children, older adults, women who are pregnant, and women who are breastfeeding shouldn’t use this essential oil blend without first consulting their medical provider.

You should also talk to your provider before use if you have a serious health condition or any skin conditions, such as eczema.

As with their benefits, more research is needed on the risks of these essential oils.

If you’re looking for ways to protect yourself or your family from getting sick, there are a few other things you can do to support your immune system:

Get enough sleep

Sleep is very important to help your immune system function properly.

A 2015 research review suggested that being sleep deprived can weaken immunity, potentially increasing inflammation and the chance of infection.

Skimping on sleep can significantly affect your overall health. So get your Zzz’s and make sure your kids get plenty of sleep as well.


A research review from 2016 found that mindfulness meditation, which focuses on being present and aware, may help strengthen the immune system.

Specifically, it may be associated with reduced inflammation and mechanisms that protect against cell aging. Still, more research is needed on the effects of meditation on immune function.

Meditation may also help you sleep better, making it a win-win.


According to research from 2018, regular exercise may boost your immune system and lower your risk of chronic disease and infections.

For an even better pick-me-up, get your exercise outside for fresh air and vitamin D, which research indicates may be vital for immune function.

On Guard is sold exclusively through doTERRA, so it’s not available in stores. However, you can purchase it online directly from the company. You can also order the oil or request a sample from a local distributor.

Other essential oil blends use similar ingredients as On Guard and may be available at different prices.

The blends Fighting Five from Edens Garden, Immunity Boost from REVIVE, Thieves from Young Living, and Immune Strength from Rocky Mountain Oils combine similar essential oils as On Guard. A main difference is that they contain lemon essential oil instead of orange.

Note that Edens Garden does not recommend ingesting essential oils without talking to a qualified health professional. Thieves is also intended for external use only.

Be sure to consult your healthcare provider before using essential oils. It’s important to tell them about any and all alternative treatments you’re using.

They can work with you to assess the potential risks and benefits, as well as to prevent any interactions with medications that you’re currently taking.

We can now get through the winter seasons without constantly passing things around. If my kids do get something, they often can kick it out within 12 to 24 hours!
— Leah Outten