There are dozens of essential oils, all with different fragrances and chemical makeups. Which essential oils are best depends on what symptoms you’re looking to ease or fragrances you prefer.

Some of the most popular essential oils include:

Lavender oil:

Many people find the lavender scent relaxing. It’s often used to help relieve stress and anxiety and promote good sleep.

Tea tree oil:

Also called melaleuca, this essential oil was used by Australia’s aboriginal people for wound healing. Today, it’s commonly used for acne, athlete’s foot and insect bites.

Peppermint oil:

There’s some evidence peppermint essential oil helps relieve irritable bowel syndrome (IBS) symptoms when taken in an enteric-coated capsule (from a trusted health supplement provider). It may also relieve tension headaches when applied topically.

Lemon oil:

Many people find the citrusy scent of lemon oil a mood booster. It’s also often used in homemade cleaning products.

How to find quality essential oils

The most important thing to consider when shopping for essential oils is product quality. But figuring out which oils are the best is challenging since there’s no government agency in the U.S. that provides a grading system or certification for essential oils. A big problem? Many companies claim their essential oils are “therapeutic grade,” but that’s just a marketing term.

Unfortunately, there are lots of products you might find online or in stores that aren’t harvested correctly or may have something in them that isn’t listed on the label.

Here are some tips to help you shop for pure essential oils:

Look at the label:

It should include the Latin name of the plant, information on purity or other ingredients added to it.

Choose dark-colored, glass containers:

Pure essential oils are highly concentrated. They can dissolve plastic bottles over time, tainting the oil. Most companies package essential oils in small brown or blue glass bottles to protect the quality.

Avoid “fragrance oils”:

Fragrance or perfume oils are made from essential oils combined with chemicals or entirely from chemicals. They’re not suitable for aromatherapy — instead, look for bottles that contain a single essential oil in its purest form (100% essential oil with no other fillers).

Compare prices:

Essential oils range in price, depending on how involved harvesting and production are. Within a line, there should be a wide variety of prices — rose absolute or sandalwood oils will be more expensive, while sweet orange oil will be on the less expensive end. If you find a rock-bottom price for an expensive essential oil, it probably isn’t pure.

Essential oils can lift your mood and make you feel good with just a whiff of their fragrance. For some people, they may even help alleviate the symptoms of various conditions. For more information on how to incorporate them into a healthy lifestyle, consult an integrative medicine expert.