Sunscreen truths

Why you can get sunburnt despite using sunscreen. By Kirsten Braun

woman wearing hat with sunscreen on back

There has been much discussion in the media of late about sunscreen and its effectiveness. People have reported getting sunburnt despite applying sunscreen. Sunscreen failure, however, is often due to how well the sunscreen is applied and/or stored. Read our tips for ensuring that you are adequately protected from the sun’s damaging rays.  

Check the expiry date

Sunscreens actually have an expiry date. After this date the sunscreen’s effectiveness may be reduced. While a sunscreen should last for a number of years, the length of time to the expiry date can depend on how long the stock has been on the shelf prior to purchase. Some people have reported buying sunscreen that was close to its expiry date.


While most people put sunscreen on initially, they often forget to reapply. When you are having fun at the beach or pool it is easy for time to pass before you realise. To maintain the protection from the sun, sunscreen needs to be reapplied every two hours. The active ingredient in the sunscreen stops working after this time. Swimming, exercising, sweating or towel drying can mean sunscreen wears off even earlier. In these cases, reapplying the sunscreen more frequently is preferable. Even sunscreen that claims to be water resistant for four hours still needs to be reapplied more regularly.

Use enough

Many people underestimate the amount of sunscreen they require to provide adequate protection. Sunscreen can be an expensive product and so people often use less than they require. Typically people use less than half the required amount, therefore, significantly reducing their sun protection. An average-sized adult should apply approximately one teaspoon (5 ml) for each arm, leg, body front, body back and face (including the neck and ears). This is about 35 ml of sunscreen for the entire body. If you consider that a 200 ml bottle of sunscreen contains less than 6 applications, it gives you an idea of how much sunscreen we should be applying.

Understand sun protection factor (SPF) ratings

The difference between a sunscreen with a SPF of 30 and that of one with a SPF of 50+ is very minor. For example, a SPF30 sunscreen provides 96.7% protection from sunburn and skin cancer, while a SPF50+sunscreen provides 98% protection. People often mistakenly assume that SPF50+ sunscreens provide twice as much protection or last twice as long, but this is not the case. 

Not relying on make-up with sunscreen

Most make-up does not have a high SPF. Even if it does it is unlikely that women apply enough make-up to be effective as it is a product that is generally applied far less liberally than sunscreen. The other issue is that many women would not reapply the make-up through the day so the length of time they are protected from the sun might be relatively short.

Correct storage

The effectiveness of sunscreen can be reduced if it is stored in temperatures that are too high. Avoid storing it in the car’s glovebox or leaving it out in the hot sun at the beach. If possible, store sunscreen in a cooler bag on hot days and replace it if it shows signs of deterioration such as looking separated or grainy.

Not relying completely on sunscreen for protection

While sunscreen is an important part of sun protection, it should be used in conjunction with other sun safe practices. Wearing a broad-brimmed hat, sunglasses, protective clothing and seeking shade are all additional strategies that can be used to reduce sun exposure.

What to look for in a sunscreen

There are two main types of sun protection, chemical and barrier. A chemical sunscreen contains chemical filters (e.g., Octylcrylen, Avobenzone, Octinoxate), which absorb ultraviolet (UV) rays. They can be more irritating to the skin. A barrier sunscreen uses zinc or titanium oxide to form a protective layer that reflects the UV rays. Traditional barrier sunscreens gave a ghost-like appearance and were more difficult to apply. However, new formulations use nanotechnology to make the particles smaller and, therefore, easier to apply and with a better appearance. Some sunscreens now contain a combination of chemical and barrier protection. The type of sunscreen you choose depends on individual preference and circumstances. Whether you choose chemical or barrier sunscreen or a combination of the two a sunscreen should be:

  • A SPF of 30 or higher

  • Broad spectrum (offers protection from both UVA and UVB rays)

  • Within expiry date.

Last updated: March 2017.

© Women's Health Queensland Wide Inc. This article was written by Kirsten Braun and reviewed by the Women's Health Queensland Wide editorial committee. It was published in Health Journey 2017 Issue 1.


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