Need some guidance getting started with your essential oil adventures? Our experienced in-house aromatherapy authorities weigh-in with answers to some of your most frequently asked questions to provide the trustworthy information you need to start blending, crafting, and diffusing with confidence!
FAQs by Topic
Essential oil basics
Essential Oil Safety
Essential Oil Care & Preservation
Essential Oil Diffusers
Diluting Essential Oils
Measuring Essential Oils
Essential Oil Basics
What Are Essential Oils?
Essential oils are highly concentrated plant essences used in natural fragrances, skin and body care, natural DIY home cleaning solutions, and aroma-support recipes. Essential oils are produced from all sorts of aromatic plants and resins and are extracted through the art of distillation, cold expression or, in the case of absolutes, solvent extraction.
Why Do Plants Produce Essential Oils?
Essential oils can be found throughout many parts of a botanical, from roots, flowers, and fruit peels, to leaves, twigs, and grasses. They are produced for a variety of reasons, including protection from predators (animals or insects interested in snacking on the plant) or to attract wildlife that helps pollinate and propagate for future plant generations.
What Should I Look for to Find High-Quality Essential Oils?
- Purity: Essential oils are pure aromatic plant oils without diluents. Some essential oils on the market are cut with a carrier or diluted with lesser quality products, so make sure the oils you are considering contain only pure plant oils. Avoid buying anything with the term “fragrance oil” as these are often synthetically produced and are not true botanical essential oils. For ease of use, you may opt to purchase the botanical's essence as a blended absolute—just be sure that the product is clearly labeled with its ingredients.
- Accuracy: Look for the Latin name on the product label to be sure you are getting the botanical you are expecting. For example, Peppermint (Mentha piperita), should be listed clearly.
- Toxin-Free: Because essential oils are very concentrated, any pesticides or other toxins used to cultivate the plant source material can be distilled into the final oil as well. Purchase oils that are certified organic or sourced from a supplier you trust (some essential oils are made from wild-harvested plants or plants cultivated without chemicals, so they may lack the organic certification but still be safe to use).
Are Mountain Rose Herbs Essential Oils “Therapeutic Grade”?
When first starting out, many beginning aromatherapy enthusiasts look for oils that are Therapeutic Grade. This distinction, however, is not an industry standard and is not endorsed or regulated by any governing agency. It is purely a marketing claim. You can learn more about this issue by visiting: AromaWeb, National Association for Holistic Aromatherapy, or the Alliance of International Aromatherapists.
Our essential oils come from carefully vetted (and whenever possible, certified organic) growers and processors and are verified by our experienced in-house Quality Lab, led by our AHPA award-winning Director of Quality Assurance and Quality Control. Quality testing documentation for our essential oils and other offerings is free and available upon request to those seeking specific information about any of our pure plant essences.
Are Absolutes Stronger Than Essential Oils?
Absolutes are not considered stronger than distilled or cold pressed essential oils. Rather, they are simply the result of a different method of extracting an herbal essence. Certain materials are not able to be distilled or will yield almost nothing from the extraction; for example, with jasmine, the heat from distillation damages the petals and will not extract their oils. In these cases, a plant’s essence is extracted using a solvent, such as alcohol, which is later removed from the pure plant essence. Oftentimes, absolutes can be very thick and difficult to work with. In such cases, you may choose to opt for a blended absolute, which should be clearly labeled with its ingredients.
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Essential Oil Safety
Why Dilute Essential Oils?
Once extracted, essential oils are highly concentrated aromatic ingredients. It takes a great deal of plant material to produce a small amount of oil—one drop of organic rose essential oil contains 60 whole flowers! Such potency means that, for most uses, diluting your essential oils is a good practice. Essential oils should always be properly diluted before applying them to the skin, and just a few drops added to an essential oil diffuser can create an immersive fragrance experience that can last for hours. Generally, essential oils are safe when diffused or diluted properly and used externally.
Can I Use Essential Oils on My Skin?
Due to the potency of essential oils, we typically recommend that they be diluted to 1% to 2% in a carrier oil for topical use on healthy adults. They can also be used in a bath soak blend, aroma spray, or in other body care products. When working with a new essential oil for use on the skin, it is a good idea to do a small patch test with the finished product to check for sensitivity or skin irritation before applying to a larger area of the body. Some essential oils are naturally more irritating to the skin then others. If an essential oil causes skin irritation, discontinue use. Every body is different, and an oil that causes skin irritation for one person may be totally fine for a someone else.
What Essential Oils Should Not Be Applied to the Skin?
Some oils are phototoxic, which means that if these oils are applied to skin that is exposed to sunlight or ultraviolet light shortly after, burns or blisters can develop. Angelica and tagetes are examples of such oils, as well as many cold-pressed oils in the citrus family, such as lime, lemon, or grapefruit. However, not all citrus oils follow this trend (sweet orange is one such exception), and while they are typically cold-pressed to preserve their delicate scents, those that are steam-distilled tend not to exhibit phototoxic properties.
Are Essential Oils Safe to Eat?
Mountain Rose Herbs labels all of our essential oils for external use only. This labeling is mandated by the American Herbal Product Association’s Code of Ethics. Essential oils are extremely concentrated, and we do not recommend them for internal use for safety and regulatory reasons.
If taken internally in large amounts or with prolonged and high frequency, essential oils can cause damage to the liver and kidneys from the aromatic compounds they contain. This is because the aromatics must be removed from the blood by the liver and kidneys, and these organs can become overloaded. It is possible that internal use can eventually even cause liver or kidney failure. Additionally, essential oils should not be used in the eyes or any mucus membranes to avoid burns or other injury to these delicate tissues.
If you wish to obtain the benefits from a botanical internally, we recommend ingesting the herbs as food or seasoning, steeped as a tea, or as herbal extracts/tinctures, capsules, syrups, or elixirs, forms which our bodies have more experience processing.
Can I Use Essential Oils Around My Kids, Pets, or While Pregnant/Nursing?
Not all essential oils are okay for everyone. Essential oils are generally not indicated for use on those who are pregnant or breastfeeding, for infants or young children, people with serious medical conditions, or pets—especially cats. The National Association for Holistic Aromatherapy has an excellent webpage on safety information for essential oils and is a wonderful resource, and Erika Galentin’s The Family Guide to Aromatherapy also offers helpful guidance in this area.
We list specific precautions in each of our essential oil profiles, as well as general precautions for use. We reference Essential Oil Safety, 2nd Edition by Robert Tisserand and Rodney Young to obtain our oil-specific precautions, which is considered the industry standard reference for essential oil safety. We also recommend that you thoroughly research a specific essential oil or contact a licensed aromatherapist, naturopath, or qualified healthcare practitioner to make sure it is safe for your purposes before use.
How Should I Store My Essential Oils?
Essential oils are flammable and should be stored away from flame, heat, and ignition sources. Additionally, essential oils should be stored out of the reach of children and pets to avoid accidental ingestion. Always store essential oils in glass and out of direct sunlight in a temperature-controlled area.
How Should I Dispose of Essential Oils?
While pure essential oils contain only naturally occurring plant compounds, the concentrations of these organic chemicals are high enough to make them considered hazardous waste. Essential oils should not be dumped down the drain or thrown in the trash. Essential oils no longer suited for aromatherapy can be added to a passive oil diffuser (which allows them to disperse gradually into the atmosphere) or added to natural DIY cleaning formulations (in properly diluted amounts). Please contact your local sanitation department for details on how to safely dispose of larger oil quantities.
Can Essential Oils Be Sent Through the Mail?
Because essential oils are flammable and/or combustible, they fall under Federal Aviation Association restrictions. With proper packaging, essential oils can be shipped to many destinations safely, but there are limits on the ways and destinations essential oils can be sent. You can learn more about how we ship our essential oils on our website.
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Essential Oil Care & Preservation
How Long Do Essential Oils Last?
When stored correctly, essential oils can last a long time. Conservatively, you can keep properly stored oils for at least one year, and some will last five or more. To determine if an essential oil is still appropriate for general use, monitor for changes in scent, color, or consistency.
Can Essential Oils Become Rancid?
Essential oils will oxidize over time from exposure to oxygen and their age, but they don't have the fatty acid compounds like olive, flax, or other carrier oils. Therefore, they will not become "rancid," but they will change color and scent. Oxidized oils should be disposed of and not used on the skin.
What Can Damage Essential Oils?
ESSENTIAL OIL DAMAGE FROM HEAT:
Essential oils are flammable, and while their flash points (the temperatures at which they will ignite) are generally quite high, essential oils should be kept well away from open flame.
Heat can also damage your precious oils, so avoid storing them above a range or wood stove, as the heat rising from such heat sources can accelerate oil degradation.
To reduce the risk of heat damage, you may choose to refrigerate your essential oils. This measure is not necessary for all essential oils, but those which are cold-pressed, such as most citrus oils, will benefit from being stored in a refrigerator (oils extracted by this method have a shorter shelf life than steam-distilled varieties). Note that refrigerating essential oils will cause them to temporarily cloud and sometimes thicken or solidify, but these effects will subside once the oil warms to room temperature.
ESSENTIAL OIL DAMAGE FROM LIGHT:
Storing essential oils in direct sunlight can affect their color and, consequently, their constituents. To maximize shelf life, store your essential oils away from regular sunlight.
ESSENTIAL OIL DAMAGE FROM OXYGEN:
Oxidation occurs when an essential oil is exposed to oxygen. Frequent and prolonged contact with air will deteriorate the oil and increase evaporation. Oils that have been overexposed to oxygen can still be used for cleaning product recipes and even some diffusion, but they should not be used for most aromatherapy applications and should not be applied to the skin.
ESSENTIAL OIL DAMAGE FROM MOISTURE:
Moisture is also detrimental to pure essential oils. Essential oils should be stored in airtight bottles with their lids tightly secured when not in use (this will also help reduce essential oil loss due to evaporation). Signs of water infiltration include cloudiness in the oil and water beading up at the bottom of the container.
What Are the Best Containers for Essential Oils?
Essential oils are best stored in glass bottles with simple, airtight lids. Amber or cobalt glass bottles are preferred over clear glass (which is how essential oils are usually sold).
Store essential oils in the smallest practical container to help reduce oxidation and contamination, since a smaller space offers less room for air and water to hide. For example, consider transferring a half-full 4 oz. bottle of lemon essential oil into a 2 oz. bottle to maximize shelf life.
Never store pure essential oils in plastic bottles—they are corrosive and will eat away at the container (plastic caps made for this purpose are fine). For this reason, screw-on lids with squeeze-top glass droppers (not to be confused with reducer caps) should not be used long-term, as the bulbs of a dropper are made from a very pliable rubber and will break down quickly if used as a lid.
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Essential Oil Diffusers
How Do I Diffuse Essential Oils for Aromatherapy?
Essential oil diffusing equipment comes in countless forms, ranging from simple porous pendants to high-tech atomizers. Different types of diffusers are appropriate for different settings, and it is important to choose an option that makes sense for your needs. For example, a passive clay diffuser would be a safe option to fill a small, moving space such as a car, while a diffuser that uses a candle as its heat source would obviously not.
Most essential oil diffusers fall into one of three categories.
pASSIVE dIFFUSERS:
Passive diffusers are simple pieces of porous material that absorb a few drops of essential oil at a time and then gradually disperse it into the air through evaporation. Common materials for passive diffusers include clays like terra cotta or naturally porous stones like pumice. Small, bead-like diffusers of this type are often marketable as wearable items like necklaces or bracelets, but we advise caution in placing any undiluted essential oil against the skin for prolonged periods, as doing so may result in skin irritation and/or sensitization.
Water Diffusers:
Essential oil diffusers commonly use water to disperse oils in mist form. These diffusers come in many varieties, ranging from simple ceramic candle diffusers to modern electronic versions; both use heat sources to diffuse the oil via steam and can spread scent throughout small to medium sized spaces, depending on the model.
For water diffusion without heat, ultrasonic diffusers create a fine mist by using ultrasonic vibrations and water to dispense essential oils into the air. This dispersion method can fill medium-sized spaces (often up to 250 square feet) with scent.
Waterless Diffusers:
A waterless diffuser disperses essential oils without the use of heat or water. Instead, an atomizer creates super fine particles of essential oils that are distributed using air. The mist created by a waterless diffuser will be slightly more concentrated than that which is created by a water diffuser, making it most appropriate for medium to larger spaces (up to 400 square feet).
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Diluting Essential Oils
What Dilution Ratios Should I Use When Working with Essential Oils?
BODY CARE:
Essential oils should be diluted for safe use, especially in formulations designed to be applied to the body such as a massage oils, lotions/salves, or aroma spray. For these recipes, essential oils should make up 0.5% to 2% of your end product. This equates to about 3 to 12 drops per fluid ounce of finished product.
PERFUME:
For natural fragrance blends intended to be used in small amounts on localized parts of the body, you may choose to incorporate a higher ratio of essential oils to allow your scents to shine. In such recipes, essential oils may account for up to 5% of your blend’s total volume.
POTENCY VARIATION:
Different types of essential oils may vary in strength. For example, cinnamon leaf essential oil is less potent than cinnamon bark essential oil, so it’s important to do your research about the nature of the oils you want to use, especially when formulating your own recipes.
Essential Oil Dilution Chart
Essential Oil Dilution Calculator
We offer a FREE calculator to help you create properly diluted recipes featuring essential oils: GO TO THE DILUTIONS CALCULATOR
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Measuring Essential Oils
How Do I Convert Drops of Essential Oil to Other Measurements?
Not all essential oil drops are equal; differences in viscosity will impact the volume of an oil that holds together in a drop.
On average: 1 milliliter = about 20 drops
There are exactly 29.57 milliliters in one fluid ounce. You may choose to round to 30 milliliters when working with recipes with total yields under 4 ounces, but exact measurements should be used for larger quantities, as those missing 0.43 mL (from rounding 29.57 up to 30) start to add up and impact your results.
Use a measuring tool and unit that makes sense, opting for drops when needed and teaspoons/milliliters/ounces when appropriate.
Essential Oil Measurement Conversion Chart
Essential Oil Measurement Calculator:
We offer a FREE calculator to help you convert between measuring units to scale your essential oil recipes up or down: GO TO THE CONVERSION CALCULATOR
