What is the difference between SPF 30 vs SPF 50 sunscreen to protect against the harsh Australian sun?
First, how harsh is the Australian sun?
Very. As illustrated in the map below, where areas with extremely high levels of UV are highlighted in red and pink. It does take only a few minutes to get sunburnt during the Australian summer. Adequate protection is essential, all year round, as soon as UV index reaches or exceeds 3.
What many consumers don’t realise is SPF30+ complies with the older 1998 standard, while SPF30 and SPF50+ comply with the latest standard dated 2012. This new 2012 standard bring 2 major improvements.
The most important improvement is in the UVA protection arena: UVA has been found to be primarily responsible for skin ageing and skin cancer. 1998 standard did not impose any substantial protection against these UVA. This has been fixed by the 2012 standard.
The second improvement, and most relevant to this article, is the significant increase in claimable SPF. Many SPF 30+ (1998 standard) or SPF30 (2012 standard) products have an SPF 30 vs SPF 50 (+) sunscreens have an SPF of 60 or greater, doubling the protection compared to SPF30 or SPF30+ sunscreens.
Sunscreens, when applied correctly, are designed to reduce skin burn-time by the claimed SPF factor. In other words, if an unprotected skin burns in 5 minutes, it will burn in 150 minutes when protected by an SPF30 sunscreen, and in 300 minutes when protected by an SPF50+ sunscreen. By design, SPF50+ is doubling the protection compared to SPF30 or SPF30+.
Now then, how absorbing 1.3% more UV rays is doubling the protection?
It is easy to confuse transmission and absorbance, which are two different things. As the graph below illustrates, UV absorption increases by 1.3% going from SPF30 to SPF60, but the UV transmission rate is cut by half, and SPF protection doubled.
The most important fact to remember is: what matters is not the UV rays that don’t reach the skin (absorbed), but those which do (transmitted).
To use a food analogy: A 98% salt-free product contains 2% salt, and a 99% salt-free product contains 1% salt. The difference between the two products is not 1% of “salt-free”, but double the salt load, which can be the difference between life and death for some.
The damage that UV light does to our skin is exactly the same: it’s the UV light that reaches our skin that matters, and using a spf 30 vs spf 50 sunscreen halves the protection.
Our tip: most consumers don’t apply the dose used to determine sunscreen SPF performance. Our recommendation is to apply sunscreen liberally, let it dry, and then re-apply the same sunscreen again. This should help ensure a sufficient load of UV filters onto your skin to reach the performance required under our harsh Australia sun.