Zinc oxide

Mineral UV filter15–25%

A white mineral filter that covers UVB and long UVA rays, suited to sensitive skin and children.

What it is

Zinc oxide is a fine white powder that sits on the skin and absorbs UV across UVB and UVA, including the long UVA rays many filters miss. It is the main filter in mineral sunscreens and the usual choice for babies, children and reactive skin. Higher levels can leave a white cast, so particle size and tint shape the finish.

Good for

Broad spectrum protectionLong UVA protectionMineral sun protectionSensitive skinBaby skin

How it works

Tiny zinc oxide particles absorb UV energy and release it as a small amount of heat, and only a small share is reflected. Its absorption runs from UVB through to about 370–380 nm, so on its own it gives balanced UVA protection. Smaller particles look clearer on skin but cover slightly less long UVA.

Ratings

Evidence

5/5

Decades of use, with protection measured in SPF and UVA tests.

Gentleness

5/5

Rarely irritates or sensitises the skin.

Formulation difficulty

4/5

Dispersion, white cast and viscosity drift all need careful work.

Cost

3/5

Cheap per kilo, but high loadings and coated grades lift unit cost.

Popularity

5/5

Central to Australian mineral, kids' and sensitive-skin ranges.

Pairs and cautions

Pairs well with

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

Take care with

Acidic actives such as AHAs or ascorbic acidZinc dissolves at low pH
Carbomer-only gelsZinc ions thin them
Avobenzone, with coated or uncoated gradesNeeds supporting stability data

Formulations it suits

Cream Lotion Sun stick Balm

Packaging

Regional considerations

Australia	Permitted in ARTG-listed sunscreens with no maximum strength, and labels need not state particle size. After 2025 recalls of zinc products sharing one base formula, independent SPF testing matters.
New Zealand	Sunscreens are cosmetics in New Zealand with no pre-market approval, but the Sunscreen (Product Safety Standard) Act 2022 makes AS/NZS 2604:2012 mandatory, whereas the TGA requires the 2021 edition.
European Union	Annex VI allows 25% in total across standard and nano grades. Neither may be used where it could be inhaled, such as aerosol sprays, and nano grades must be labelled '(nano)'.
United States	One of two long-standing filters the FDA has proposed as safe and effective (GRASE), at up to 25%; the FDA added bemotrizinol to the monograph in June 2026. Every US sunscreen is an OTC drug and must carry a Drug Facts label.

In the lab

Specifications

Typical use level

15–25%0525%

pH window

pH 6–82 acid7 neutral10 alkaline

Solubility

ParticulateOil-dispersibleWater-dispersible

Sensitive to

Low pH

Alone, 15–25% can reach SPF 50+ with strong UVA cover. Alongside organic filters, 5–15% is common and adds long-UVA protection.

INCI	Zinc Oxide
Also known as	ZnO, Mineral filter, Physical sunscreen (older term)
Origin	mineral

Lab notes

Solubility and phase

Disperse in the oil or water phase to suit the grade's coating, with a matched dispersant, as it is insoluble.

Stability

Use a coated grade, such as silica, alumina or silicone, and track agglomeration, viscosity rise and SPF drift across shelf life.

Regulatory, Australia

Permitted sunscreen active with no maximum concentration (Permissible Ingredients Determination No. 3 2026), and particle size need not be declared. Primary sunscreens and moisturisers above SPF 15 are therapeutic goods, generally ARTG-listed (AUST L), tested to AS/NZS 2604 and labelled with approved names and set warnings.

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. 'Chemical-free' and 'physical block' are inaccurate, and 'non-nano' must match supplier particle data.