Sunscreen: Everything you need to know

Sunscreen: Everything you need to know

What is SPF? How much sunscreen do you need? Is kids’ sunscreen different? Read on!

What is SPF? How much sunscreen do you need? Is kids’ sunscreen different from adult sunscreen? Read on!

Summer is in full swing, and that probably means you’re spending more time outside, having fun and soaking up that precious vitamin D

You know what’s not fun? Sunburn from UVB radiation or less immediate but no less dangerous long-term impact of UVA radiation.

So with that, let’s break down everything you need to know about sunscreen, SPF, how to choose the right products, and how to use them.

Shop sunscreen in the Mednow Wellness Shop

Choosing a sunscreen: What to look for

sunscreen tips: Hands squeeze out lotion-style sunscreen in front of a blue patterned beach towel

Browsing the shelves for sunscreen, it’s easy to be overcome with the dozens of different sunscreen options. The paradox of choice is real. How are you supposed to know which one to choose?

Evaluating these factors will help you pick the best product for your needs:

UVA and UVB protection

Ultraviolet A — or UVA — rays from the sun don’t cause sunburns. However, they can deeply penetrate the skin, causing wrinkles and increasing skin cancer risk. 

Ultraviolet B — or UVB — rays do cause sunburns. The SPF number on the sunscreen bottle refers to protection against UVB rays. 

Exposure to both UVA and UVB rays presents risks. To protect yourself from these two types, look for a broad-spectrum sunscreen that addresses both UVA and UVB.

Look for a product that is specifically labelled as broad-spectrum and that protects against both UVA and UVB radiation. In terms of active ingredients, these are some of the names to look for:

  • Avobenzone
  • Cinoxate
  • Ecamsule
  • Octyl methoxycinnamate
  • Oxybenzone
  • Salicylates
  • Sulisobenzone
  • Titanium dioxide
  • Zinc oxide

Shop sunscreen in the Mednow Wellness Shop

Water and sweat resistance

Look for a sunscreen that is water and sweat-resistant. These products are specially formulated to stay put and protect your skin even when you’re swimming, sweating heavily, etc.

Keep in mind that water and sweat-resistant sunscreen still requires regular reapplication. If you’re not diligent about applying them often, you could still end up getting burned.  

Skin sensitivity

If you have sensitive skin, look for a sunscreen formulated with conditions like eczema, psoriasis, and allergies in mind.

The following ingredients can sometimes be problematic for people with sensitive skin:

  • Para-aminobenzoic acid (PABA)
  • Dioxybenzone
  • Oxybenzone
  • Sulisobenzone
  • Avobenzone

Instead of relying on these ingredients, consider using sunscreen a zinc oxide or titanium dioxide sunscreen. Where other sunscreen products are absorbed into the skin, these options are “physical” sunscreens that form a physical UV-deflecting barrier on the skin.

If you have sensitive skin or allergies, you may need to avoid sunscreens that contain fragrances or dyes, too. These ingredients can also irritate some people’s skin.

What is SPF?

SPF stands for Sun Protection Factor. It’s a number that measures how much UV radiation — or solar energy — it blocks. 

The amount of protection you get from sunscreen increases marginally as the SPF number increases. For example:

  • SPF 15 blocks approximately 93 percent of UVB rays
  • SPF 30 blocks approximately 97 percent of UVB rays
  • SPF 50 blocks approximately 98 percent of UVB rays
Sunscreen tips: An artistic shot of the sun shining through a hand making a circle with its forefinger


Wearing sunscreen that blocks UVB rays is certainly important when it comes to protecting yourself from sunburns and the immediate and lasting damage sunburns can cause. However, you can see that there are diminishing returns as SPF numbers climb and SPF isn’t the only factor to consider.

Shop sunscreen in the Mednow Wellness Shop

Sunscreen SPF and skin protection

A lot of people look at a sunscreen bottle and assume that a higher SPF number means more skin protection. It’s not that simple, though.

Technically, the higher the SPF number, the longer it’ll take you to burn. However, a higher SPF does not mean you need to reapply less frequently. Regardless of the SPF number, it’s important to reapply sunscreen at least every two hours. 

Other factors can also influence your sunscreen’s effectiveness. This includes your activity level, UV index on a particular day, certain medications and health conditions. Skin type also plays a role; skin with less pigmentation is typically more sensitive to sun than skin with more pigmentation. 

In addition, the type of sunscreen you choose has an impact on how well it protects. You can see how wel you’ve covered your skin with lotion type sunscreen. With spray-on sunscreen, you need to take extra care to ensure full coverage. 

What is the difference between kids and adult sunscreen?

Short answer: There is no difference between sunscreen marketed toward kids or sunscreen marketed toward parents. At least, not in terms of formulation or active ingredients.

Also note that Health Canada does not recommend using sunscreen on children under six months.

Kids sunscreens contain the same active ingredients as adult sunscreens. They just have fun labels, they might feature a favourite character or play on parents’ desire to protect their kids.

There’s no difference in the amount of protection the products provide, as long as they have the same active ingredients and are both water and sweat-resistant. 

In other words, there’s no need to have one sunscreen for the kids and one for the adults. Adults can use “kids” sunscreen and kids can use “adult” sunscreen.

When should I apply sunscreen?

Apply your sunscreen at least 15 minutes before going outside. Reapply at least once every two hours while outside, too.

If you burn easily, you may need to reapply sunscreen more frequently. Ditto if you’re spending a lot of time in the water.

How much sunscreen should I use?

It takes approximately 35 millilitres (or seven teaspoons) of sunscreen to cover exposed skin.

For full coverage, apply one teaspoon (5ml) to each arm and one teaspoon to each leg. Then, apply one teaspoon to the front of the body — the chest and abdomen — and one teaspoon to the back. Finish with one teaspoon on the face and neck.

Sunscreen tips: A graphic depicting a teaspoon with the words "use seven teaspoons of sunscreen for total coverage" appearing in the centre.

We’re not saying you should take a literal teaspoon on your outdoor adventures (but hey, you do you). That said, it’s a good idea to know what a teaspoon of sunscreen looks like before you head out for the day. Also note that this is a guideline only; more skin area will require more sunscreen for proper coverage.

More sunscreen tips

With that, and after waiting the required 15 minutes after applying sunscreen, we’re ready to head out into the sun. Before we go, a couple of final take-away tips:

  • Check the weather forecast, paying special attention to the UV index
  • When applying sunscreen, don’t forget the tops of the ears, feet, nose and exposed scalp
  • Wear a hat
  • Look for a lip balm with an SPF rating. Lips need protection too
  • Set a timer on your phone and reapply sunscreen every couple of hours

Speak to an expert

If you have any questions about sunscreen or anything health-related, your Mednow pharmacist is here to help. Chat with a Mednow pharmacist in the Mednow app (Apple | Android | web browser) or by calling 1-855-MEDNOW-1 (1-855-633-6691).

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