Try it when: You’re feeling stressed.
How it works: The scent of lavender is thought to calm the nervous system. In one study, people exposed to the smell of lavender oil while waiting for a dental appointment reported feeling less anxiety than did those in an unscented room. Try adding 4 to 6 drops to a warm bath or mixing the oil with water in a spray bottle to mist into the air. (Bonus: Some research suggests it might also help fight hair loss when massaged into the scalp.)
Good to know: To relieve sore muscles, combine 5 drops with 5 drops of peppermint oil and 4 teaspoons of a carrier oil, then massage into skin.