If you suddenly find yourself lingering at the bathroom sink at 9 p.m., living for the scent of a favorite jasmine-infused night cream, you’re not alone. The aromatic oil, which offers a natural calming lift, can have a powerful effect on emotional well being. Any doubts, just consider this fact: Even before the global pandemic sent self-care rituals into overdrive,  essential oils were well on their way to becoming a 15 billion dollar industry by 2025

And for good reason, according to Dr. Nadim Shaath, Ph.D, an organic chemist specializing in the industry. “For the last 20 years, essential oils have helped us get away from a lot of the synthetic stuff that’s not necessary,” he says, explaining that natural materials like the essence of a plant can also directly affect the emotional center of the brain, known as the limbic system. From soaking in a hot bath with Hinoki scented salts to wiping down your yoga mat with fresh tea tree oil, these acts can be healing in and of themselves. “Just like how chamomile is good for digestion, there are oils that ground you and promote good sleep, like lavender, and powerful antioxidants that are good for rheumatism, skin and hair, [like rosemary and cedarwood].”

But the potent and volatile oils obtained from natural raw materials of plant origin are not without controversy. 

“Plants are like amazing chemical factories,” says Gay Timmons, a clean beauty expert and organic ingredients distributor, explaining that tea tree has 150 plus chemicals in its oil that have evolved to help protect it from harsh conditions, like rain which makes for wet soil, where fungus and mold like to grow. “When we start screwing around with their chemistry, fractionating their oils, synthesizing them, or mixing them with other materials,” things get complicated.

Here’s a guide to understanding essential oils, and how to navigate them safely and effectively.

Plant Purity is Everything

Purity is the single most important test when it comes to understanding the quality of an essential oil. “With tiny molecules, [authentic] essential oils have the ability to penetrate the skin deeply and enter the bloodstream quickly… delivering healing medicinal plant compounds to every cell in your body,” says Kirsten King, a clinical aromatherapist and founder of the innovative organic essential oils company Oille. On the other hand, if an oil is adulterated with contaminants or diluents like benzyl alcohol, a human allergen, to increase volume for profit, it can be potentially dangerous. How often does that really happen? With no industry regulation, some sources estimate that a staggering 80% of oils sold commercially are impure.

For the best chance of high quality essential oils, it’s important to buy from a supplier that upholds strict purity standards. Ollie, which strives to raise the bar on transparency, uses a professional technology called GC/MS (Gas Chromatography and Mass Spectrometry), which tests for purity and plant DNA and is performed by the company’s independent botanical chemist who specializes in essential oils for clinical use. 

As a general rule of thumb, if the brand or retailer can’t tell you where the oil comes from, buy it from somewhere else. Obtaining the botanical name as well as the manner in which it was distilled and the harvest date is recommended, too. Don’t be fooled by pretty packaging either. “Phrases like ‘therapeutic-grade’ or ‘3rd party verified’ are simply marketing jargon,” says King. 

Since potentially harmful side effects can be by-products of age, bacteria, yeast or mold, it’s important to understand an oil’s shelf life, which differs across the spectrum. Even when stored in a cool and dark place, citrus oil and peppermint oil tend to go bad faster than lavender, which can last up to 6 years. If you’re unsure, 2 years, which is the shelf life required by the FDA for most personal care products, is a safe bet. And if the oil develops a sharp odor,  throw it away.

Skincare...and the Smart Way to Dilute

Some mainstream skincare companies, such as Drunk Elephant, avoid essential oils due to their reputation as being sensitizers and their association with photo-toxicity, which occurs when an oil like bergamot or lemon is applied to skin and exposed to ultraviolet light, causing a rash, redness — or even a chemical burn. This is why details like how an oil is extracted matters: Bergamot is photo-toxic when cold-pressed, but it’s not photo-toxic when it is steam-distilled.  

Another factor to consider: Not all natural oils are suitable for skin application (for example, lavender is widely-considered okay for topical use; cold-pressed bergamot is not). If an oil is safe, it still should be mixed with a carrier oil — and cautiously. Oille recommends that its pure oils get diluted up to 3% with a carrier oil. That means, with 1 oz of base oil, like olive oil, use 5 or 6 drops of essential oil for 1% dilution and 15 to 18 drops for 3% dilution. Keep in mind, says King, that each person has different reactions to every essential oil. 

A safe rule of thumb is to stick to less than 5% of any given plant extract in a skincare formula to avoid the chance of a flare up.

Decode the Labels—Then, Inhale

So, what can you do to distinguish between real essential oil, and fake? Look for botanical names and warnings on the labels that convey extensive knowledge like “for external use only” or “avoid applying directly to skin,” says King, who lists how each oil was cultivated and extracted as well as provides a plant’s chemistry and compound makeup directly on the packaging. 

Shaath suggests looking into a source’s farm—as well as that farm’s sustainability and human welfare practices. Many farms have their workers harvesting overnight, for consecutive nights, because the sun can evaporate some of the plant’s aroma, as well as cause enzymes to break down the material. “It doesn’t mean that a little distillery in Eugene, Oregon can’t give you a nice peppermint—of course it can—but on a mass scale, you need to make sure you’re getting an authentic material from an authentic supplier,” he says.

Above all, perhaps the biggest indicator of an authentic essential oil besides its higher price—it takes 8 thousand flowers to produce one kilogram of rose oil, says Shaath—is your nose. “If it smells off, or it’s giving you a headache, you need to check its sources."

Why Essential Oils are Worth It

It sounds like a lot of work for a little glass bottle and a few drops of scent. But of course, many in the industry believe these oils do more than give your face oil a transportive fragrance.

“Essential oils innately know how to heal, and boost our immune system, through co-evolution as humans’ first medicine,” says King, who has a deeply personal relationship with Melissa, a soft lemony oil that reminds her of her late brother every time she smells it. Known for removing emotional blocks, it helped her overcome years of grief. “When genuine essential oils are used authentically, they have the power to release emotions connected to memories that no longer serve our highest good.” At their best,  King continues, they also have the potential to imprint our most meaningful positive experiences on the psyche through "scent memory that is woven into our DNA," making it possible to conjure loved ones or experiences across continents and even generations.  Pretty powerful, indeed.  

Want more clean beauty explainers? Check out our easy guide to understanding "fragrance" on a cosmetics label. For more info on Westman Atelier's clean beauty mission, click here!