Ingredient review
Butylbenzotriazole Siloxane
INCI: Bis(Butylbenzoate) Diaminotriazine Aminopropyltrisiloxane
A modern synthetic UV filter that provides broad-spectrum protection with low irritation potential, but its safety data is still emerging compared to older filters.
In plain English
This ingredient is a man-made molecule that acts like a tiny umbrella for your skin. When sunlight hits it, it absorbs the UV rays and turns them into harmless heat, which then dissipates. It's designed to be stable and not break down quickly in the sun, so your sunscreen stays effective longer. Because it's a larger molecule, it sits mostly on the skin's surface rather than soaking in deeply, which helps reduce the chance of irritation.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Butylbenzotriazole Siloxane is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Butylbenzotriazole Siloxane.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A synthetic organic compound belonging to the triazine family, chemically modified with siloxane (a silicone-like group) to improve its stability and feel on the skin. It is a UV filter that primarily protects against UVB and some UVA rays.
How it works
The molecule contains a special structure that absorbs high-energy UV photons. When UV light hits the molecule, it excites the electrons, and as they return to their normal state, the energy is released as low-energy heat. This prevents the UV energy from reaching and damaging skin cells. The siloxane part helps the ingredient spread evenly and resist washing off with water or sweat.
Pros
Excellent photostability
Unlike some older filters that break down quickly, this ingredient stays effective longer under sunlight, meaning your sunscreen protection lasts longer without needing frequent reapplication.
Low irritation potential
Because it's a larger molecule that doesn't penetrate deeply into the skin, it's less likely to cause stinging, redness, or allergic reactions, making it a good option for sensitive skin types.
Cons and cautions
Limited regulatory approval
This filter is not yet approved by the FDA for use in the United States, so you'll mostly find it in sunscreens from Europe, Asia, or other regions. This limits availability for US consumers.
Less research history
Compared to decades-old filters like avobenzone or zinc oxide, there is less long-term human safety data available, though current evidence suggests it is safe at typical use levels.
Best for
- People looking for a stable, broad-spectrum chemical sunscreen
- Those with sensitive skin who react to older UV filters like oxybenzone
Use caution if
- Anyone seeking a mineral-only sunscreen (e.g., zinc oxide or titanium dioxide)
- Those who prefer ingredients with a very long history of use
Usage tips
Safety summary
Current safety assessments from European and Australian regulators consider this ingredient safe for use in sunscreens at concentrations up to 10%. It shows low skin penetration, low irritation, and no evidence of hormone disruption in available studies. However, long-term human exposure data is still limited compared to older filters.
Research notes
Studies indicate this UV filter is photostable and effective at absorbing UVB and some UVA rays. Human patch tests show low irritation potential. Environmental toxicity data is sparse but initial findings suggest low acute toxicity to aquatic organisms. More independent research is needed on long-term systemic effects.
Common label clues
- Typical concentration
- Up to 10% in leave-on products
- Regulatory status
- Approved as a UV filter in the EU, Australia, and several Asian countries at concentrations up to 10%. Not yet approved by the FDA in the United States, where it is not listed as a permitted sunscreen active ingredient.
- Common uses
- Sunscreens, Daily moisturizers with SPF, Anti-aging products
- Environmental note
- As a synthetic compound, its environmental impact is less studied than mineral filters. However, it is not known to be a significant coral-reef toxin based on current research, though more data is needed.
Good to know
- This ingredient is often combined with other UV filters to achieve broad-spectrum coverage, especially for UVA protection.
- It is not a nanoparticle and does not leave a white cast like some mineral sunscreens.
Common questions
What is Butylbenzotriazole Siloxane in beauty products?
This ingredient is a man-made molecule that acts like a tiny umbrella for your skin. When sunlight hits it, it absorbs the UV rays and turns them into harmless heat, which then dissipates. It's designed to be stable and not break down quickly in the sun, so your sunscreen stays effective longer. Because it's a larger molecule, it sits mostly on the skin's surface rather than soaking in deeply, which helps reduce the chance of irritation.
What does Butylbenzotriazole Siloxane do in a beauty product?
The molecule contains a special structure that absorbs high-energy UV photons. When UV light hits the molecule, it excites the electrons, and as they return to their normal state, the energy is released as low-energy heat. This prevents the UV energy from reaching and damaging skin cells. The siloxane part helps the ingredient spread evenly and resist washing off with water or sweat.
Is Butylbenzotriazole Siloxane safe for most people?
Current safety assessments from European and Australian regulators consider this ingredient safe for use in sunscreens at concentrations up to 10%. It shows low skin penetration, low irritation, and no evidence of hormone disruption in available studies. However, long-term human exposure data is still limited compared to older filters.
Who should be careful with Butylbenzotriazole Siloxane?
Anyone seeking a mineral-only sunscreen (e.g., zinc oxide or titanium dioxide) Those who prefer ingredients with a very long history of use
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.