Research has shown that scents play a big role in how the brain functions - and how you ultimately feel.

It's no accident that a whiff of lemon on a spring day makes you feel just a bit cheerier. A Japanese study on 12 participants diagnosed with depression found that a citrus fragrance (made mostly of lemon) markedly lowered the dosages of antidepressants the patients needed. It also boosted immune function and regulated hormone levels.

Try adding the scent of jasmine to your bedtime routine (just be sure to blow out the candle before dozing off!). A study presented at the Eastern Psychological Association Conference in 2011 found that when 20 participants slept in rooms scented with jasmine, they moved less during sleep and rated their anxiety levels lower, compared to when they slept in rooms scented with lavender or nothing at all.

To set the mood, light a candle. In a study conducted by The Smell and Taste Treatment and Research Foundation of Chicago, a variety of scents were found to get fellas in the mood. One of them? Cinnamon buns. Others on the list included pumpkin pie and donuts (combined), black licorice, buttered popcorn, cheese pizza and roasting meat. We're sensing a theme here.

If you don't have a lawn to mow to get that "freshly-cut grass" scent, light a candle. Australian researchers have found that the scent of freshly cut grass directly affects the part of the brain that's responsible for emotion and memory, and can ultimately lower stress. Preventing chronic stress means lower blood pressure, less forgetfulness and a stronger immune system.

Aromatherapists often suggest rosemary for an effective Monday morning pick-me-up. It has stimulating properties that fight mental fatigue, physical exhaustion and headaches. Try lighting a rosemary candle on those days you just can't get out of bed.

Just the smell of olive oil can help curb your cravings by making you feel full. In a study from the German Research Center for Food Chemistry, researchers found that having the scent of olive oil associated with dinner reduced how many calories participants consumed and improved their blood sugar response.