Ingredient Education · Titanium Dioxide · Feb 16, 2026

Titanium Dioxide

Titanium dioxide tends to spark strong opinions. In ingredient conversations, it is often framed as completely safe as long as it is not in powder form, or as something that should be avoided entirely. As with most ingredients, the reality is more nuanced.

Titanium dioxide is a naturally occurring mineral processed into a fine white powder. In cosmetics, it is widely used to provide opacity, brightness, and ultraviolet protection. It appears in foundations, concealers, mineral powders, pressed powders, and sunscreens, including products marketed as “clean.” From a formulation standpoint, it is stable, effective, and inexpensive. That combination explains why it is so common.

The strongest and most clearly established concern involves inhalation of fine or ultrafine particles. Organizations such as the International Agency for Research on Cancer have classified inhaled titanium dioxide as “possibly carcinogenic to humans,” based primarily on animal inhalation studies. Occupational health agencies focus heavily on this route of exposure because repeated inhalation of respirable particles has been associated with lung inflammation and related effects. This is why loose powders, aerosolized cosmetics, and spray products raise the most significant red flags. When particles become airborne and small enough to be inhaled deeply into the lungs, exposure dynamics change considerably.

That inhalation concern is legitimate and well documented. However, it is not the only area researchers have examined.

Some toxicology research has explored titanium dioxide beyond respiratory exposure, particularly in laboratory and animal models. Under certain conditions, especially when exposed to ultraviolet light, titanium dioxide has been shown to generate reactive oxygen species. These are unstable molecules capable of interacting with cells. When reactive oxygen species accumulate beyond what the body can comfortably neutralize, this creates oxidative stress. Oxidative stress is not synonymous with immediate damage. It is a biological process that, depending on dose and context, may contribute to inflammation or cellular irritation over time.

High-dose animal and in vitro studies are designed to identify biological mechanisms and establish safety margins. They do not automatically translate to everyday cosmetic use. However, when an ingredient demonstrates measurable biological activity under stress conditions, it reinforces the importance of thoughtful, limited use rather than assuming complete inertness.

Much of the reassurance around topical titanium dioxide centers on limited skin penetration. Research generally indicates that titanium dioxide does not significantly penetrate intact, healthy skin. That is an important part of the safety discussion. At the same time, limited penetration does not necessarily mean zero interaction. Variables such as particle size, nanoparticle formulations, ultraviolet exposure, compromised skin barriers, and frequency of application remain areas of ongoing study. Much of the available research evaluates shorter-term exposure rather than lifelong, daily use beginning in childhood.

For me, this ultimately comes down to necessity and cumulative exposure. Titanium dioxide is typically included for opacity, brightness, or UV reflectivity. In many cosmetic products, alternatives exist that can fulfill those roles. When an ingredient has a clearly established concern via one exposure route and demonstrates measurable biological activity in laboratory models, I consider that sufficient reason for thoughtful discretion when alternatives are available.

I do not view titanium dioxide as an immediate danger, and I do not believe a single exposure is catastrophic. At the same time, I do not see a compelling reason to contribute to overall particle load when alternatives are available that better align with my formulation philosophy. That is why titanium dioxide is on my Ingredients We Avoid list and why I choose not to use it in my products.

When evaluating ingredients, I look at function, dose, cumulative exposure, and necessity. Titanium dioxide simply falls into the category where I prefer to err on the side of simplicity when possible.

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