Aromatherapy is the practice of harnessing the therapeutic properties of scent. “Aroma affects your psyche. Stress symptoms like sweating, increased heart rate, and stomach cramps are controlled by hormones," says aromatherapist and co-founder of the New York Institute of Aromatic Studies, Amy Galper. "Certain scents tell the brain not to release those stress hormones. A specific pleasurable scent can create a new emotional reaction to things.”

Practicing aromatherapy at home is easy. Decide what you are aiming for—help with sleep or stress, for example—and choose three to five essential oils from each mood group on the opposite page. “Aromatherapy works best when oils are combined,” says Galper. To create a custom blend, combine two drops of each of your chosen three to five essential oils (10 drops maximum if you are using five essential oils) into two tablespoons (or one ounce) of olive oil (or another natural oil). You can either massage the blend into your skin or put it in a bath.

As essential oils are highly potent, pure chemical compounds, it’s important to dilute them with olive oil before applying them to your body or adding them to a bath. You can apply your custom blend anywhere on your body, but placing it on your wrists, chest, shoulders, or neck so you can easily breathe in the scent will ensure you get the full effects. You can also try using a diffuser. A nebulizing diffuser that vaporizes the oils into a fine mist without using heat or water is best.

STRESS-BUSTERS

Floral essential oils such as lavender, rose, jasmine, ylang-ylang, and neroli calm and soothe the central nervous system, low- ering the body’s stress response. Flower oils contain ingredients that help you slow down and calm down emotionally.

ENERGIZERS

When you want to recharge, reach for fennel seed, rosemary, peppermint, and eucalyptus to make you feel more alert and focused. These oils also help with clearing mucus and detoxifying your system.

MOOD ELEVATORS

To help banish the blues, choose scents that are uplifting and energizing, such as citrus oils including lime, lemon, grapefruit, and sweet orange. “These oils are cleansing and detoxifying, so the physical action affects the emotional. They help body and mind let go of the negative and embrace the positive,” says Galper.

SLEEP ENHANCERS

If you have any trouble relaxing and falling asleep at the end of the day, turn to lavender, clary sage, ylang-ylang, and red mandarin. Lavender has sedative qualities, clary sage and ylang-ylang relax muscles, and red mandarin works to quell nerves.

This story originally appeared in Beauty From the Inside Out by Bobbi Brown.