Bisoctrizole

Organic UV filter1–5%

An organic filter supplied as tiny particles in water, giving photostable broad-spectrum cover and steadier avobenzone.

What it is

Bisoctrizole is a carbon-based UV filter made into microfine particles and sold as a water dispersion. It absorbs and scatters UVB and UVA and helps keep avobenzone from breaking down. Because it is particulate, higher levels can leave a light white cast.

Good for

Broad spectrum protectionUVA protectionUVB protectionLightweight sun protection

How it works

Each particle absorbs UV across UVB and UVA, with peaks around 305 and 360 nm, and also scatters some light, which boosts the oil-soluble filters around it. Because it sits in the water phase, it adds protection without adding oiliness.

Ratings

Evidence

4/5

Well documented, though less studied than mineral filters.

Gentleness

4/5

Rarely irritates, though one dispersion ingredient can sensitise.

Formulation difficulty

3/5

Added late as a dispersion, with care around salts and white cast.

Cost

4/5

Speciality filter, priced above commodity filters.

Popularity

3/5

Used in some Australian next-generation launches.

Pairs and cautions

Pairs well with

In a routine. Pairing in one formula depends on matching pH windows.

Take care with

High-electrolyte or cationic basesDestabilise the dispersion

Formulations it suits

Lotion Gel-cream Cream

Packaging

Regional considerations

Australia	Permitted up to 10% as active, about 20% of the usual 50% dispersion. Labels need not state that the dispersion is nano-sized.
European Union	Annex VI allows 10% for standard and nano grades combined. The nano grade must meet set specs, cannot be used where it could be inhaled and must be labelled '(nano)'.
United States	Not an approved filter under the FDA sunscreen monograph, so a US sunscreen using it as an active would need an approved new drug application.
Canada	Health Canada's sunscreen monograph allows up to 5%, half the Australian and EU limit, in sunscreens sold as non-prescription drugs.

In the lab

Specifications

Typical use level

1–5%0525%

pH window

pH 5–72 acid7 neutral10 alkaline

Solubility

ParticulateWater-dispersible

1–5% as active, which is 2–10% of the 50% dispersion. Add it to the water phase, even after emulsifying, for broad UVA and UVB cover.

INCI	Methylene Bis-Benzotriazolyl Tetramethylbutylphenol (nano)
Also known as	Tinosorb M (BASF), MBBT, Methylene bis-benzotriazolyl tetramethylbutylphenol (Australian Approved Name)
Origin	synthetic

Lab notes

Solubility and phase

Post-add the 50% aqueous dispersion to the water phase or cooled emulsion with gentle mixing, as the particles are insoluble in oil and water. The dispersion also carries decyl glucoside, propylene glycol and xanthan gum, and suits cold process.

Stability

Store the dispersion frost-free and mix it before use, then check viscosity and SPF after ageing.

Regulatory, Australia

Permitted sunscreen active, maximum 10% as active (Permissible Ingredients Determination No. 3 2026). Primary sunscreens and moisturisers advertised above SPF 15 are therapeutic goods, usually ARTG-listed (AUST L), tested to AS/NZS 2604 and labelled with approved names and set warnings; sunscreen lip products and tinted foundations that meet the Determination’s conditions are excluded.

Claims to take care with

Use only TGA-permitted indications, such as 'SPF 50+ broad spectrum very high protection', and skin-cancer, sunspot or solar keratosis claims need broad spectrum SPF 30 or more. Do not call it 'mineral' or 'non-nano', as it is an organic filter in nano form.