Many beauty companies are making millions off the soothing scents of aromatherapy products. Placebo effects on the human body and mind are long known but the researchers wanted to see if the smells would improve human health in a measurable way.
Researchers from the Ohio State University decided to test lemon and lavender, two of the most popular aromatherapy scents, and see if their stress-relieving and healing properties were true.
A series of different tests showed that there were none. In a few cases, even distilled water had more effect than lavender.

The researchers taped cotton balls laced with essential oils and distilled water to the nostrils of 56 healthy male and female volunteers and subjected them a series of tests.

They tested if the smells would help manage pain, improve healing, have any impact on their mood and stress levels. Each of the participants was tested previously to make sure that each had a normal sense of smell.

The study showed that neither the lemon nor lavender oil had any positive effects on the immune system or the body's ability to lessen the pain or alleviate the stress.

Lemon oil was found to be a clear mood enhancement though.
The study’s authors reported that they failed to find any quantitative indication that these oils have any physiological effect on people.

“But the human body is complexed, they also said, and there's no way to prove that essential oils don’t improve the health of the person who felt better after using the oils."