Sunscreen 101: When to Use It, How Much to Apply & Why Technique Matters

Geoff Acton
Dec 15
3 min read

Australia experiences some of the highest UV levels in the world, which means correct sunscreen use is essential — especially during summer. But while most Australians use sunscreen regularly, studies show many apply too little, apply too late, or forget to reapply. Here’s a simplified, evidence-based guide to using sunscreen properly.

When Is Sunscreen Actually Necessary?

Use sunscreen when the UV Index is 3 or above (Henderson et al., 2022)

Across most of Australia, the UV Index exceeds 3 for much of the year (Whiteman et al., 2019). On these days, applying sunscreen as part of your morning routine helps reduce both incidental and intentional UV exposure.

However, daily sunscreen is not always needed. When UV levels stay below 3, sun protection isn’t generally recommended — unless you work outdoors, spend long periods outside, or are around reflective surfaces like snow or water.

Different skin types need different levels of protection

Fair, sun-sensitive skin: apply daily when UV ≥ 3, even for short outdoor tasks (Neale et al., 2024).
Olive or medium skin: apply daily when UV ≥ 3 and spending more than ~20 minutes outdoors (Neale et al., 2024).
Deeply pigmented skin: routine daily sunscreen isn’t required, but recommended during prolonged outdoor exposure of 2+ hours when UV ≥ 3 (Neale et al., 2024).

In many northern Australian cities, UV remains above 3 year-round; in southern regions, it fluctuates — so checking the UV forecast is the easiest way to know what your skin needs that day.

How Much Sunscreen Should You Apply?

Most people don’t use enough. Adults need around 35 mL (about seven teaspoons) for a full-body application to reach the labelled SPF:

one teaspoon for each arm and each leg
one for the front, one for the back
and one for the face/neck/scalp.

Using less significantly reduces your effective SPF (Henderson et al., 2022).

When and How to Apply and Reapply

Apply sunscreen 20 minutes before going outdoors so it can form an even, protective film (Henderson et al., 2022). Make sure to cover all exposed areas — including the ears, neck, scalp, back of hands, and anywhere clothing gaps.

Reapply every two hours when outdoors, and sooner after swimming, sweating, or towel-drying (Whiteman et al., 2019). Even water-resistant formulas eventually wear off.

Choosing the Right SPF

SPF50+ is the highest available in Australia and offers the best protection when applied correctly. If texture or whitening is a concern, modern non-nano zinc oxide formulations provide excellent clarity and elegant feel thanks to improvements in mineral dispersion technology.

Broad-Spectrum Matters

Look for “broad-spectrum” — this means the sunscreen protects against both:

UVA, which penetrates deeply and contributes to ageing and melanoma; and
UVB, which causes sunburn and is strongly linked to skin cancer.

Non-nano zinc oxide remains the only single UV filter proven to cover the full UVA and UVB spectrum with exceptional photostability.

Don’t Rely on Sunscreen Alone

When UV is 3+, combine sunscreen with protective clothing, a broad-brim hat, sunglasses, shade, and avoiding peak UV hours where possible. These behaviours work together to significantly reduce long-term UV damage.

The Takeaway

Sunscreen is simple to use — but how you use it makes all the difference. Apply the right amount, apply early, and reapply often on high-UV days. When UV stays below 3, daily sunscreen isn’t required unless you’re outdoors for long periods or around reflective surfaces.

Smart, consistent habits — paired with suitable sun-safe products — help protect your skin all year round.

References

Henderson, S., King, K., Karipidis, K., Tinker, R., & Green, A. (2022). Effectiveness, compliance and application of sunscreen for solar ultraviolet radiation protection in Australia. A Journal of Public health Research & Practice, 32(1). https://doi.org/10.17061/phrp3212205

Whiteman, D., Neale, R., Aitken, J., Gordon, L., Green, A., Janda, M., Olsen, C., Soyer, H., Sunscreen Summit Policy Group. (2019). When to apply sunscreen: A consensus statement for Australia and New Zealand. Australian and New Zealand Journal of Public Health, 43(2), 171-175. http://doi.org/10.1111/1753-6405.12873

Neale, R., Beedle, V., Ebeling, P., Elliott, T., Francis, D., Girgis, C., Gordon, L., Janda, M., Jones, G., Lucas, R., Mason, R., Monnington, P., Morahan, J., Paxton, G., Sinclair, C., Shumack, S., Smith, J., Webb, A., & Whiteman, D. (2024). Balancing the risks and benefits of sun exposure: A revised position statement for Australian adults. Australian and New Zealand Journal of Public Health, 48(1). http://doi.org/10.1016/j.anzjph.2023.100117