Why should I use a sunscreen?
- UVB damages your skin cell and melanocytes (the cells that give you skin colour and protect against the sun). Damage to these cells causes skin cancer.
- UVA penetrates deeper into the skin and damages collagen. Collagen serves as scaffolding and shock absorber to protect deeper structures of the skin. It also gives volume to the skin. UV damage to collagen results in wrinkles, sagging skin and easy bruising.
- Broad spectrum sunscreens offer protection against skin cancer and premature aging of the skin.
Wrinkling on the sun-exposed side after 28 years of working as a truck driver.
What is SPF?
- SPF stands for sun protection factor. It is a measure of the fraction harmful UVB rays that reach the skin. For example, "SPF 20" means that 1/20 of harmful UV rays reach the skin when the sunscreen is applied appropriately. In other words, if takes you 10 minutes to get sunburnt without sunscreen, it will take you 20 times longer (200 minutes) to get sunburnt with SPF 20 sunscreen adequately applied.
What is the difference between chemical and physical sunscreens?
- Chemical sunscreens absorb the energy from the UV rays and convert it to other forms of energy that do not damage the skin. Their advantage is that formulations they are easier apply and rub into the skin without leaving a white residue. This makes them cosmetically more acceptable. Their disadvantage is that they are slightly less effective than physical sunscreens and can cause irritation.
- Physical sunscreens form a shield on the surface of your skin that reflects or deflects UV rays before they reach your skin. They are cosmetically less acceptable but they are less likely to cause skin irritation.
What is non‐comedogenic sunscreen?
- This is a sunscreen that does not contain oily substances that predispose to formation of blackheads, whiteheads and acne.
What is a “sensitive skin” sunscreen?
- These generally are physical sunscreens and do not contain irritants and allergens such as fragrances, preservatives, and synthetic dyes.
What are baby sunscreens?
- These are typically physical sunscreens without fragrances or other irritants.
- They are similar to “sensitive skin” sunscreens.
Which sunscreen should I choose?
- Broad-spectrum sunscreen which protects against UVA and UVB rays.
- SPF 30 or higher. Higher SPF sunscreens are more likely to have good UVA protection and give some margin for error if under applied.
- Use water-resistant sunscreen when sweating, exercising or swimming.
- Physical sunscreens if you have a sensitive skin or react to sunscreens
- Rather buy enough of the sunscreen that you can afford to use continuously rather than buying an expensive which you have to use sparingly or intermittently.
When should I apply sunscreen?
- Apply sunscreen every time you are outside, even on a cloudy day up to 80 percent of UV rays still reach the exposed skin.
- Apply sunscreen to dry skin at least 15 minutes before going outdoors.
- The need for sunscreen is even more in water, snow or sand because they reflect harmful UV rays back to the skin.
- Reapply every two hours when you are outdoors or immediately after swimming or sweating regardless of the SPF you use.
How much sunscreen should I apply?
- Most people only apply 25-50 % of the recommended amount of sunscreen.
- You need enough sunscreen to fill a shot glass (25ml in South Africa) to cover an average adult body not covered by clothing. With increasing clothes cover, proportionately less is required.
What is the difference between regular, water-resistant and waterproof sunscreens?
- Currently there is a global drive to remove the label waterproof from sunscreens because no sunscreen is waterproof.
- A water-resistant sunscreen retains its SPF activity after immersion in water for at least 40 minutes.
Do people with dark skin need to use sunscreen?
- Darker skin is much less susceptible to sunburn and UV damage than lighter skin.
- White residue from physical sunscreens is more visible on darker skin making it undesirable cosmetically and limiting options.
- Darker skin is more susceptible to hyperpigmentation that is aggravated by UV rays. In this group of patients there is good evidence supporting use of sunscreen.
- In general, there is no good evidence to support or refute the benefit of sunscreen to prevent skin and premature skin aging in darker skinned individuals.
Are sunscreens safe?
- There is a general consensus that the benefits of sunscreens outweigh potential risks.
I hope this helps in your choice of sunscreen.
Prof Rannakoe Lehloenya
