How much sunscreen do you really need for your face and neck? | Ask Doctor Anne

Now that we have talked about the different forms of sunscreen, the best one for sensitive skin and the importance of UVA protection, it is time to talk about the most important things:


How much sunscreen do you really need for your face and neck?
But: How much sunscreen do you really need for your face and neck?


How much sunscreen do I need for my face and neck?

How often do I need to reapply?

And: What about my Vitamin D levels?

These were among the questions I got quite frequently, so I decided to dedicate a whole video to that topic. As always you need to adapt what I say to your individual lifestyle, which makes it a little more complicated. But don´t worry, we will figure it out!


A few words on the importance of getting the right amount

Whenever I hear „A little goes a long way“ in regards to sunscreen, I die inside. Wherever you stand on sustainability and minimalism, sunscreen application is more a thing of „Go big or go home“ as not applying the correct amount will drastically reduce the amount of protection you get.

Even worse, you will think you are protected, because you applied sunscreen, and probably be less cautious with seeking shade.

For a long time we thought that applying half the recommended amount would give us half the protection, so SPF 25 instead of 50 for example, but studies have shown that this is not true. Reducing the amount of sunscreen applied by a quarter already reduced the protection by half, which means that half the recommended amount of SPF 50 will actually give you an SPF of… 10.


How much sunscreen do you need to apply for your face and neck?

2mg of product per square centimeter of skin.

Now that is helpful – not!

I don´t know when you did measure your face for the last time, but for me that was – never. That doesn´t mean that no one does though, I am going to link to a video where LabMuffin Beauty did it, but most of us will most likely need a rule of thumb.

For obvious reasons it is better to apply too much than too little, so a good rule of thumb is ½ teaspoon for face and neck.

Which brings us to the next problem: If you like to cook, you know how hard it can be to eyeball measurements, especially if you use an ingredient for the first time.

The solution? Measure it, pour it into your hand and get accustomed to how it should look like. To do that you can either use a measuring spoon or a good kitchen scale – for the average face it should be around 2g of product. I did that in the video and believe me, it is quite a lot!

Over time you will get better at eyeballing the right amount.


How often should I reapply?

Let me start with a quote from a popular skincare blog here:

You really do not have to reapply sunscreen every two hours. Sunscreens are broken down by the effects of direct exposure to daylight, not by the passage of time. During an average day – a work day, let’s say – the sunscreen you applied in the morning will still offer enough protection at the end of the day.

I disagree.

While sunscreen is indeed broken down by direct exposure to daylight, which means the protection lasts longer, the less UV exposure you get, it also disappears due to sweating and rubbing, which means that every time you touch your face, you lose some of the even layer needed for protection.

And I don´t know about you, but I touch my face a lot – even though I know I shouldn´t because Corona and breakouts and stuff.

So even without UV exposure, after 4 hours you have most likely rubbed away a substantial amount of protection and should reapply.

The next thing to consider is the filters you are using. Some, like Avobenzone, are unstable if not used in conjunction with other stabilizing ingredients, which means that even without UV light they lose their protection value (you can read more about the different kind of filters here), so if you apply them in the morning before doing your makeup and then leave the house two hours later, you might already have lost your UVA protection.

The rule I (try) to live by is: When I am outdoors, think beach, hiking, gardening – I reapply every two hours.

When I am indoors, working, I reapply every 4 hours, which roughly translates to before my lunch break and before I go home again. For full disclosure: In the colder months I reapply in the mornings and maybe before I leave the office (I go by bike). If it is already dark then I don´t bother reapplying at all.

As for the question: How do I reapply sunscreen over a full face of makeup – I will do a blog post on that soon showing you different ways as so many of you asked.


What about my Vitamin D levels? Will I get deficient if I wear that much sunscreen?

While the skin needs UVB light to generate Vitamin D, that does not necessarily mean less UVB exposure equals less Vitamin D. If that were true people living far away from the equator would have lower Vitamin D levels by default, as the amount of UVB light that reaches the earth there is much lower over the course of the year.

In addition Black people would be more prone to Vitamin D deficiency, as their naturally melanated skin competes with the UVB rays.

Both isn´t true. In fact we have found that nutrition is a much more common reason for Vitamin D deficiency than regular use of sunscreen, which explains why the Inuit, getting very little UVB due to where they live and how they are bundled up against the cold, still have good Vitamin D levels due to a diet that traditionally contains fatty fish as source of Vitamin D.

Other than fatty fish, which might not be everyone’s cup of tea, egg yolk and mushrooms do provide some Vitamin D too, and some types of milk and orange juice are “fortified” with Vitamin D as well.

I get that this diet can be problematic if you try to minimize the intake of animal protein, which is where I think a supplement does come in handy. Supplements are usually not my method of choice, I am a firm believer that a balanced diet is the way to go, but in that case I would rather take a supplement than risk skin cancer. (Always check in with your doctor first, obviously!)

I promise you however that no matter how diligent you think you are with applying and reapplying your sunscreen, chances are there is more than enough skin left uncovered, think hair line, hands, feet and such that you get enough UVB for adequate Vitamin D levels.


How much sunscreen do you really need for your face and neck?
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