How Much SPF You Actually Need
If you’ve been around here for a while, you already know how strongly I feel about sunscreen. To sum up just how passionately I feel about sunscreen, if you aren’t using sunscreen (or enough sunscreen, for that matter) you might as well throw out every bit of skincare you have.
In honor of this, I want to break down exactly how much sunscreen you actually need, why the amount matters so much, and the most common SPF mistakes I see patients making.
Why The Amount of Sunscreen Matters
Let’s get into the science of it (briefly), when sunscreen is tested in a lab to determine its SPF rating, it’s applied at a very specific amount: 2 milligrams of sunscreen per square centimeter of skin. That might sound technical, but what it really means is that the SPF number on the bottle assumes you are applying a fairly generous layer of sunscreen. So if you are applying far less than that amount (which most people do), the level of protection drops dramatically.
I also think that now is the perfect time to remind you that sun damage is cumulative. Every bit of unprotected exposure adds up. This is something I talk about more in depth in my blog on how to protect, prevent, and repair UV damage, but the short version is that consistent protection is one of the most powerful things you can do for your skin long term.
The ¼ Teaspoon Rule
It probably speaks for itself, but for your face alone, you should be applying about ¼ teaspoon of sunscreen. As for covering your neck and chest, the amount is closer to ½ teaspoon total.
Here’s a little breakdown:
Face: ¼ teaspoon
Face + neck: about ½ teaspoon
Entire body: about 1 ounce (roughly a shot glass)
Now I know you are going to laugh at this, but I am actually a firm believer in measuring it out. Tbh I still do this from time to time, just to ensure I am using the proper amount.
Now My Favorite Part, Let’s Cover Some Truth On SPF
SPF in Makeup Does Not Count
Ok let me start by saying I loooooveeee when makeup has spf in it (you probably know this by looking at my skin friendly beauty list). When it comes to SPF, more is more (aka better). BUT, no matter the makeup product, I promise you, the amount you would need would be astronomical. In fact, for foundation you would typically need to apply around 7 times more product than people normally use to reach the stated SPF. And for powder formulas, that number is even higher. So while these products can add a bonus layer of protection, they should always be layered on top of a proper sunscreen application.
Mineral vs Chemical Sunscreen
While we’re on the topic of sunscreen myths, I also want to touch on something that came up in a recent podcast episode with Lab Muffin Beauty Science. There is a common belief in the skincare world, that mineral sunscreens reflect UV rays while chemical sunscreens absorb them. The truth is that both mineral and chemical sunscreens primarily work by absorbing UV radiation and converting it into small amounts of heat. The most important factor isn’t whether a sunscreen is mineral or chemical, it’s whether you apply enough (and use it consistently).
Reapplication Is Just As Important
Even if you apply the correct amount in the morning, sunscreen does not last all day. UV filters break down over time due to sun exposure, sweat, natural skin oils, touching or rubbing your face, etc. Which is why dermatologists universally recommend reapplying sunscreen every 2 hours when you are in direct sun. Now I recognize that this concept can be daunting, and I am all about skincare being manageable. So my best suggestion is to apply it before you go outside for a walk, the park, or even a drive. If you are outside all day, then I really do recommend setting an alarm and reapplying every 2 hours. Finally, if you work inside all day, then I usually suggest just trying to re-apply once.
I talk about this much more in my blog on how to reapply sunscreen over makeup, but my personal method is very simple:
I squeeze about ¼ teaspoon of the same sunscreen as my base onto the back of my hand
I use a clean beauty blender or brush
I gently press the sunscreen into the skin over my makeup
Is there a tiny bit of makeup disruption? Yes. But the trade-off for real sun protection is completely worth it in my opinion.
Why I Personally Prefer Tinted Sunscreen
You may have noticed that I recommend a lot of tinted sunscreens. There’s a reason for that. Tinted formulas typically contain iron oxides, which help protect the skin from visible light, a type of light that can worsen conditions like:
redness
If you're looking for options, I broke down my favorite sunscreens for every skin type in another blog, including several tinted formulas I personally wear on repeat.
A Simple SPF Cheat Sheet
I love a cheat sheet, so consider this your official spf sheet!
Face → ¼ teaspoon
Face + neck → ½ teaspoon
Body → about 1 ounce (a shot glass)
And some rules:
Apply every morning
Reapply every 2 hours if outdoors
Reapply before going outside and ideally at least once a day, if you are mainly inside
Don’t forget commonly missed areas like ears, neck, chest, and hands
Alright that covers it! As always, let me know what you want me to cover next! We are going to end with good news, I have a Skincare Guide that will go into so much detail on product recommendations, routines, etc. If you are serious about nailing your skincare routine down, I highly recommend it.
**Disclaimer: This post contains affiliate links and may contain products gifted in PR. This means that I may earn a small commission when you purchase via these links at no additional cost to you (thank you! It helps me keep things up and running)… As always I ONLY recommend products, goods and services that I stand behind and personally love and use
