Colour therapy has been around for 5,000 years, since ancient Egyptians wore coloured sacred stones and Hindu healers linked the colour spectrum to the body’s seven vital chakras. The theory behind this type of therapy (also called chromotherapy, light therapy and colour healing) is that each colour’s unique wavelength has a corresponding vibration speed that works to harmonize the brain and body, easing symptoms from mood disorders to lethargy.

Some scientists believe our reactions to colours are ingrained by evolution for survival; others say it’s merely the result of ever-present powers of association (black may make you feel sad, for example, if it reminds you of funerals). Either way, colour therapy is practised around the world. Says June McLeod, an international expert, author of Colours of the Soul and the U.K.’s leading colour consultant, “We use coloured lights pointed at specific parts of the body, colour visualizations, breathing, art therapy and colour silks to support well-being.” McLeod believes colour does transform lives—and studies may prove it.