Big names continue to fail our sunscreen tests.
Find out which of the 20 sunscreens we tested met their SPF claims.
Our accredited labs tested the sunscreens following the methods in the Australian and New Zealand standard AS/NZS 2604:2012.
We test against two aspects of the standard: a sunscreen’s SPF (sun protection factor), which measures protection against UVB rays, and its broad-spectrum protection (against UVA and UVB rays).
The standard requires SPF to be assessed using a test panel of 10 volunteers in a lab. Testing on humans determines a sunscreen’s ability to provide protection and stay on the skin without breaking down.
To determine a sunscreen’s SPF number, the sunscreen is applied to a test subject at a rate of 2mg per cm2 skin. The sunscreen is evenly spread out and allowed to dry for 15 minutes. A similar-sized area is measured out and left unprotected.
A special lamp, simulating the part of the UV spectrum that causes sunburn, is shone on both areas for varying amounts of time. The next day a technician determines the smallest dose of UV light required to cause redness in both areas and this is used to determine the SPF. Ten people are tested for each sunscreen and the SPF results are averaged.
Using a spectrophotometer, the lab measures the UVA protection passing through a thin film of sunscreen on a plate. To pass, a sunscreen has to meet two requirements. It has to reach a “critical wavelength” that ensures UVA protection extends to wavelengths that penetrate deeper into the skin. Its protection against UVA has to be at least a third of the SPF protection against sunburn.
We didn’t test water resistance.