4-Terpineol

4-Terpineol is the main component of tea tree oil. It has antibacterial, antioxidant, and anti-inflammatory properties.

This ingredient is potent at killing bacteria, making it an effective acne treatment. According to the book Journal of Profiles of Drug Substances, it helps in reducing acne-causing bacteria such as Propionibacterium acnes.

While tea tree has been found to help soothe inflammation and redness, it can also cause sensitivity and irritation in some people.

Research shows irritation usually occurs when using pure oil and not from cosmetic products.

This ingredient can be derived from several parts of the tea tree plant: leaves, branches, and bark.