Methylene Bis-Benzotriazolyl Tetramethylbutylphenol (often shortened to Methylene Bi, INCI abbreviation Bisoctrizole/Tinosorb M) is a broad-spectrum organic-mineral hybrid UV filter that absorbs and scatters both UVA and UVB radiation. It is a microfine particulate filter valued for its high photostability and ability to stabilize other sunscreen actives.
| Reported effect | How often | Notes |
|---|---|---|
Mild transient skin irritation or stinging | Uncommon | Usually mild and self-limiting, often related to the overall sunscreen formulation rather than the filter alone. |
Allergic contact dermatitis | Rare | Reported infrequently; the large molecular size limits skin penetration and sensitization potential. |
White cast or cosmetic residue | Common | A cosmetic effect due to its particulate nature, not a true adverse health reaction. |
Photoallergic reaction | Very rare | Very few documented cases; considered a low photosensitizing risk relative to some other organic filters. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.