4-Terpineol is a key active in tea tree oil that helps fight acne-causing bacteria and calm redness, but it can be irritating at high concentrations.
Irritation
moderate
Source
natural
Beauty ingredient research
Browse the review database to understand what an ingredient is, what it does in a beauty formula, when it is useful, and when it deserves caution across skincare, haircare, bodycare, makeup, and more.
20769
Reviewed ingredients
524
Low-concern standouts
2884
Need usage caution
4-Terpineol is a key active in tea tree oil that helps fight acne-causing bacteria and calm redness, but it can be irritating at high concentrations.
Irritation
moderate
Source
natural
A gentle sulfur compound that may help calm redness and support collagen production, but more human studies are needed to confirm its topical benefits.
Irritation
low
Source
natural
EPA is a marine-derived omega-3 that helps calm redness, support the skin barrier, and protect against environmental stress.
Irritation
low
Source
natural
Escin is a plant-derived anti-inflammatory ingredient that helps reduce puffiness and support microcirculation, especially around the eyes.
Irritation
low
Source
natural
Heparin may help reduce puffiness and support microcirculation in skincare, but its topical benefits are less established than its medical use as a blood thinner.
Irritation
low
Source
natural
Ibuprofen can reduce redness and swelling in skincare, but it is a drug ingredient with potential for irritation and systemic absorption, so use with caution.
Irritation
moderate
Source
synthetic
A gentle plant extract that helps calm redness and support microcirculation, often used in eye and anti-aging products.
Irritation
low
Source
natural
Sodium Heparin is a gentle, anti-inflammatory ingredient that may help calm redness and support skin recovery, but it is not a primary active for most routines.
Irritation
low
Source
natural
Ursodiol is a bile acid with emerging research suggesting it may help calm inflammation and support the skin barrier, but it is not yet a mainstream skincare ingredient.
Irritation
low
Source
semi-synthetic
Zinc Picolinate is a gentle, oil-regulating ingredient that helps calm inflammation and may reduce breakouts without drying the skin.
Irritation
low
Source
synthetic