Just 10 minutes of direct sunlight will burn your skin.
Get caught without sunscreen for several hours, and you’ll experience pain, peeling and redness.
Sunscreen is important for long-term skin health, as well as avoiding sunburn. Over time, UVB radiation causes wrinkles, lines, and discolouration. Health organisations including the NHS, the British Skin Foundation and FDA recommend sunscreen every time you go outside – not just at the beach or pool.
This page has an overview of the key facts about sunscreen.
Below you’ll find out the types, how sunscreen works, SPF ratings (and scams) and how to ensure you get the maximum protection.
What is Sunscreen Made of?
There are two types of sunscreen: mineral and chemical.
Commercial brands contain a mix of ingredients, along with unique creams or oils to make spreading it on your skin smoother.
Mineral Sunscreen: Key ingredients are zinc oxide or titanium dioxide. These chemicals work by deflecting the ultraviolet radiation from your skin.
Chemical Sunscreen: Key ingredients include avobenzone and octisalate. Instead of deflecting the sun, these chemical compounds absorb UV radiation.
Both types are tested and safe. While sunscreen brands use the ‘organic’ label in their marketing for either type, the chemicals are organic molecules.
The Low-Down on Sun Protection Factor (SPF)
If you see a sunscreen with an SPF of more than 50, it is a marketing gimmick.
EU (and now UK) regulators have found that going above SPF 50 rarely makes any difference to the protection offered.
Sun Protection Factor measures the delay in burning from the sun.
For example, if you wear a sunscreen with an SPF of 20 you will take 20 times longer to burn than usual. If you are fair skinned, and would burn in 15 minutes, then you get 20x 15 minutes (300 minutes) of sun to get to the same level. That assumes the sunscreen does not rub off or sweat does not remove it.
As well as the ‘minute multiplier’ effect, you can think of SPF in terms of the percentage of rays blocked.
Here is a guide:
- 15 SPF: Blocks 93% of UVB Radiation
- 30 SPF: Blocks 98% of UVB Radiation
- 50 SPF: Blocks 99% of UVB Radiation
There are also star ratings, which show the amount of radiation absorbed. These are for marketing by sunscreen brands, with the official SPF the key number used by health professionals.
Most People Apply Sunscreen Wrong
Sunscreen has a habit of disappearing.
It rubs off, gets washed off in the pool, slowly gets sweated out or simply fades over time.
Clever marketing like ‘all day’ clouds the issue. Some sunscreens are designed to stay on in water, and to be sweat resistance. That does not always mean the full protection remains all day.
Health organisations recommend that you reapply sunscreen every two hours. They also state that you should apply liberally – noting that most people don’t apply enough to get the full protection.
There are two more recommendations:
- Apply sunscreen every day: Damage from UV radiation is cumulative over your lifetime, and your wrinkle-free older self will thank you.
- Wear a hat and cover up: A wide brimmed hat (or even a cap) will shield you from those damaging rays, even when it is overcast.
Note that there are separate recommendations for children and babies – these are not covered on this page.
UVA and UVB Radiation (Sunscreen When it is Cloudy)
Sunlight reaching your skin has two main types of rays.
Ultraviolet A (UVA): These rays penetrate deepest into your skin, and are the main cause of ageing, wrinkles, and lines.
Ultraviolet B (UVB): These are the most dangerous rays, with the biggest role in skin cancer.
There are up to 500x more UVA rays that UVB ones. Both types of ray hit your skin even on cloudy days. You should wear sunscreen and cover up even when it is overcast. The damage from UV radiation will keep building over your lifetime. Each period you protect yourself will reduce the long-term damage to your skin.
Sunscreen 101: Wrapping Up
With today’s knowledge about the damage caused by the sun, there is no excuse not to cover up – even on cloudy days.
Modern sunscreen brands use a mix of chemical and mineral compounds. They protect you from both the dangerous types of UV radiation. Apply them generously, and frequently – with extra protection from hats a loose clothing ideal.
If you are worried about a mole, or other damage to your skin, get it checked out right away.
In the meantime, enjoy the sun safely with these travel destination / packing guides:
- What to Pack for Thailand
- Vietnam Packing Guide
- What to Pack for Tenerife
- Most Popular Seaside Towns
- Biggest Ferris Wheels
