Hello first time Skinnies users!
We get a lot of questions, especially from new users of Skinnies, about the spreadability and how can a "less is more" application possibly give you the protection we claim and, how do you know where you've put it!
The clear gel is really spreadable and while Olly hates me saying this, I reckon it takes a little getting used to before you really trust it's doing the job and you get into the swing of applying it thoroughly and sparingly. Skinnies is a sunscreen revolution afterall and something completely different from how you've always done it takes a little getting used to.
I recommend you use Skinnies thoroughly and sparingly. Less is more. The pea size blob for your face, neck and ears gives an indication of the spreadability and amount for the area of skin. After application skin feels slightly tacky for a couple of minutes before the gel dries. Use this time to "feel" that it's spread everywhere, like you would when applying moisturiser.
Well spread thorough application and sparing amounts because of the gel's substantivity. This is how well it stays on your skin which is very well as the gel is a lipid like skin so bonds to the top layers and stays there.
I personally use Skinnies once a day on myself and the children and I can still feel it on them (and myself) at the end of the day. I look for the water beading off the skin or remove my LOOKS medium with a cotton pad and some cleanser.
So let's get technical:
When sunscreen is tested in the laboratory 2mg of sunscreen is applied per cm2 of skin. While it is widely known sunscreens are not used as they should be, let's base Skinnies efficacy on this known requirement for the in vivo testing (yes sunscreen is tested on real people who sit in a spa pool to test the water resistance - more on testing in another post!).
With water based sunscreens because there’s "dry down" (water evaporating during the 20 minutes it takes them to dry) over half the film depth evaporates taking volatiles and some UV actives with it. This doesn't happen with Skinnies because there is no water. When you apply Skinnies there’s no dry down which leaves a higher actives yield (technically you can use half the film width with Skinnies ie. 1mg/cm2). This means Skinnies is more effective with a lesser amount.
Work with me here:
A typical body (back when I did physiology at uni in the 90s!) was approximately 1.5m2 in surface area. If we say we need 1mg/cm2 of Skinnies to provide the recommended thickness of sunscreen on the skin for the day we need 15g to totally cover the body.
Calculation: 1.5m2 = 15,000cm2, for 1mg/cm2 we take 0.001g/cm2 x 15,000 = 15g (we’ll use the specific gravity of water for arguments sake even though Skinnies is around .97).
So 15g of Skinnies will cover your whole naked body at the technical concentration and if we’re at the beach for around 6 hours in the full sun, during this time you would theoretically need to apply 35ml of typical sunscreen every 2 hours (if you’re using it correctly) for a total of 105ml.
So 105ml of typical sunscreen (giving you a net 1mg/cm2 coverage each application) or 15g of Skinnies. We could say you use 10 times less Skinnies but that just sounds too far fetched. Plus we know most people use sunscreen incorrectly and we don't want anyone getting sun burnt.
What I will say is that you DO need to reapply the SPF30 if you’ve been in the water for 80 minutes, though from my own experience CONQUER SPF50+ 4 hours water resistance is the business when it comes to water sports. THE. BUSINESS.
That's an "intro to Skinnies" and we'll cover the UV filters we've selected (protecting against the full range of UVA and UVB rays) in the next installment!