What the SPF?

SPF, or Sun Protection Factor is confusing.

Which number is best?
And How often do you reapply?
And how much?

Let's begin: SPF, is a measure of how much Ultraviolet radiation is getting through your skin, with a given protection.

Technically the SPF number increases your personal burn time by the SPF factor, ie; if it takes you 10 minutes to burn without sunscreen, an SPF 15 would increase your time to 150 minutes but... that's not really how it works, considering movement, time of day, intensity of sun and just sheer wearing off.


SPF only blocks out Ultraviolet B (UVB) rays, not Ultraviolet A (UVA), no matter how high the number.

UVB rays are what causes the sunburn that too many of us are familiar with.

UVA rays don't cause visible damage, but still cause skin damage and penetrate deeper than UVB rays.


To ensure UVA rays are also blocked, look for sunscreens/blocks with zinc oxide or titanium dioxide. These ingredients reflect the UVA rays away from your skin.

SPF 15 blocks out 93% of UVB rays, SPF 30, blocks out 97% of UVB rays, and that's about the extent of it.

That's why physicians recommend at least SPF 30, with a zinc oxide or titanium dioxide included in the ingredients. The higher the number the more it will block, but there's only 3% more to go, so don't think that SPF 100 is blocking out 100% of UVB rays, it is maximally around 98% protection.

After about 2 hours, most sunscreens, regardless of their percentage of UVB blocked, will need to be reapplied, sooner if you've sweat or been in the water. And who doesn't experience sweating or water on a hot sunny day!?



  • SPF 30 is just fine for most people. (Naturally, the darkest skin tone is ~SPF 15)
  • If you even think about reapplying, then it's probably time to reapply.
  • The Canadian Association of Dermatology recommends using 2-3 tablespoons of sunscreen to adequately cover an average adult body.
  • Do all this every 2 hours, and it is a lot of slathering!

I think the point here is to be aware that as the time ticks away your sun protection fades, and the more coverage, the better, so consider your own risk factors, and sun habits.

And as a wise Indian said during the colonized days:

"Only mad dogs and Englishmen go out in the midday sun"

So how about taking a little step back from sunbathing in the peak hours, and find a nice palm tree (or suitable local substitute) to sit under. Or a day at work.


The Ingredients

Since we've got to slather up to manage our sun-loving - what's inside your sunscreen? There is a lot of debate around what you should and shouldn't put on your skin.

I've gone ahead and chosen my top 3 tips for sunscreen:


Avoid creams with Vitamin A

It might sound natural, and it's great to eat but it is actually a photosensitizer - which means it makes your skin more susceptible to burning, the opposite of what we are going for.


Avoid any sunscreen with Oxybenzone

It's a hormone disruptor, I think that warrants avoidance.


If you have an infant under 6 months, do NOT apply sunscreen.

Their skin absorbs these creams too easily, and the levels of these chemicals are not intended for infants. In addition, the protective skin colour pigment (melanin), is not quite prepared for strong sun until 6 months. Which means: keep your little bebette in the shade or dappled light. (I love the word dappled).

5 Companies to choose your sunscreens from:

What I look for is Canadian owned (the first 3), organic options, and that include Zinc oxide or Titanium dioxide.

  • Green Beaver

  • Badger

  • Rocky Mountain Soap Company

  • Alba Fragrance Free

  • Aubrey Organics

  • Nezza Naturals.

I'm sure there are others!

If you are interested, check out the Just Beautiful link directly below for the top 10 ingredients to avoid in Personal Care Products.

Or get the Think Dirty App - which helps you do this in store with products