Hask® Tea Tree Oil & Rosemary Hair and Scalp Treatment Mask is blended with purifying tea tree oil and rosemary to help hydrate and soothe the scalp and hair. Tea tree oil down the shaft of the hair that helps to prevent build-up of chemicals and dead skin. This keeps your hair healthy and moisturized, which can help it grow at its normal rate and prevent it from falling out. The rosemary oil has the ability to thicken hair significantly. The blended formula is the best choice for a healthy scalp and hair.