What Is Benzotriazole?
Benzotriazole is an aromatic heterocycle made of fused benzene and triazole rings, giving it a compact structure that is both stable and highly versatile. Originally studied for its ability to prevent metal corrosion, it first entered industrial use in the mid 20th century as a rust inhibitor for copper and bronze. Over time formulators noticed its mild antimicrobial action and began experimenting with it in personal care products where controlling microbial growth is essential for product safety.
Commercially, benzotriazole is produced by reacting o-phenylenediamine with nitrous acid in the presence of solvents and controlled temperatures, yielding a white to off-white crystalline powder. The finished ingredient is purified, milled and tested for residual solvents before being supplied to cosmetic manufacturers.
Today you can spot benzotriazole in a range of water-based or emulsion-type cosmetics such as facial cleansers, sheet masks, hydrating serums, lightweight moisturizers and after-shave lotions. Its primary role is to help keep these products free from unwanted microbial growth, supporting the overall shelf life and safety of the formulation.
Benzotriazole’s Cosmetic Benefits/Uses
In skincare and personal care formulas benzotriazole serves one main purpose that offers a clear benefit.
As an antimicrobial it limits the growth of bacteria, yeast and mold in the product, reducing the chance of contamination after the jar or bottle is opened. This helps maintain formula integrity over time, supports user safety and can potentially allow for lower levels of traditional preservatives when used in combination with them.
Who Can Use Benzotriazole
Benzotriazole is generally considered suitable for all skin types, including oily, combination, dry and even acne-prone skin, because it functions inside the formula rather than on the skin surface and is used at very low levels. Those with extremely sensitive or allergy-prone skin may wish to proceed with caution, as any preservative-type agent can be a trigger for irritation in rare cases.
The ingredient is synthetic and not sourced from animals, so it is compatible with vegan and vegetarian lifestyles.
No data show specific risks for pregnant or breastfeeding women when Benzotriazole is used in a topical cosmetic product, but this is not medical advice. Anyone who is expecting or nursing should discuss all skincare choices with a qualified healthcare professional.
Benzotriazole does not make skin more sensitive to sunlight and has no known effect on tanning or pigmentation. It also has no recorded interactions with common actives such as retinoids, vitamin C or exfoliating acids, making it easy to slot into most routines.
Potential Side Effects/Adverse Reactions
Responses to Benzotriazole applied on the skin can vary. The effects listed below are possibilities only and are not expected for the average user when products are correctly formulated.
- Mild skin redness or stinging in very sensitive individuals
- Contact dermatitis in people with a specific allergy to the compound
- Eye irritation if the product accidentally gets into the eyes
- Worsening of existing eczema if the skin barrier is already compromised
If any of these reactions occur, stop using the product and seek medical advice if symptoms persist or worsen.
Comedogenic Rating
Rating: 0 / 5
Benzotriazole is water soluble, used at tiny percentages and stays mainly within the product rather than forming an occlusive film on skin. Because it is not oily or waxy it has no tendency to clog pores, so it earns the lowest possible score.
That makes it suitable for people who are prone to acne or frequent breakouts.
As with any preservative-type ingredient, the overall formula still matters. Heavy creams or balms that contain Benzotriazole could still cause congestion if the base oils are comedogenic, even though this particular ingredient is not.
Summary
Benzotriazole is a synthetic antimicrobial that keeps creams, gels and lotions free of bacteria, yeast and mold so they stay safe and stable for use. It works by disrupting microbial growth inside the product, letting the formula maintain its texture and effectiveness over time.
Although it has a long history in industrial applications, its use in cosmetics is fairly niche and you will usually spot it only in select water-based formulas that need extra microbial protection.
Current data show it is low risk for most skin types when used at customary levels and it carries virtually no comedogenic burden. Still, everyone’s skin is unique, so it is wise to patch test any new product containing Benzotriazole before applying it to a larger area.