Reader question: Can we add up SPF numbers?
Thursday, January 10, 2013 at 1:43PM Hi Liz! I just want to understand how the SPFs on multiple products work. If I use a facial moisturizer with SPF 15 and then layer it with a facial powder with SPF 15, does that mean that I'm wearing a total of SPF 30 on my face? I just want to make sure if my understanding is correct. If this is the case, then I can sparingly use a more expensive facial moisturizer with SPF 30 and then simply use the moisturizer-powder combination more frequently and I will have the same degree of protection either way. Thanks in advance for the clarification. - Maybelle
Hi Maybelle! Thanks for your question. I talked to a dermatologist before about this, and she said that it's not possible to layer SPF products to get a higher number. You will just get a higher volume of the sun screening ingredients, which means you get better protection, but it's still on the same SPF15 level. If you mix SPF15 with something that has SPF30 though, the higher number is the amount of protection your skin will receive.
The thing is most people don't apply enough sunscreen to actually maximize it. Dermatologists recommend at least a teasespoon of cream on your face and on each arm, and at least a tablespoon on each leg. But that's rather uncomfortable, isn't it? On the face I mean. That amount would feel quite thick, which is why a higher SPF number on the face is better than the bare minimum (which is SPF15). For example, if you have an SPF50 powder and only apply it sparingly, then you might get at least SPF25 out of it. This is just a guesstimate okay, so don't quote me on that!
Try a light SPF50 base like the Laneige Snow BB Soothing Cushion SPF50
My point is that we shouldn't scrimp on applying our SPF products. :) You can layer them together to get a more solid protection or choose one product that you feel is comfortable enough to slather on your face. I prefer to use a moisturizer with SPF OR my usual moisturizer + a makeup base with at least SPF30 in it.
Hope this helps!
Reader Comments (26)
I would usually just go with a BB cream with SPF. That way I can use only the bb cream as it is usually enough to even out the skin and also moisturize it.
Wow! This is helpful, because all along, I thought that SPF is cumulative because I remember a dermatologist saying this in one local morning show. Haha! Thank you for this clarification Ms. Liz! :)
This whole SPF thing seems like such a myth too me. :( Other dermatologists say the number doesn't count but I really don't know what to believe now. I'm using an SPF 30 tho just to be sure.
What is knew is that when you use a product with SPF content then layer it with another product with SPF, it will increase its sun-protection power. But Maybelle's question has a point too - I even think that way. Thanks for this informative post, Ms. Liz ;)
Try the Neutrogena Ultra Sheer Dry Touch sunblock for the face :) It's light and not greasy.
Wow this is really helpful Liz. :) all this time kala ko all the spf's in the product that I use will add up kaya I only limit the spf to 15. Usually kasi When I use a higher spf products I get breakouts. The only product that I used with a higher spf that didn't break me out is celeteque matte moisturizer spf 30, pero I find it very heavy. Do you have any suggestions on what products I can use? I am on a limited budget kasi as of now I'm a stay at home mom. Happy new year pala :)
Thank you Liz and to the other girls who also answered this query. Got your point on not scrimping. You're right, I should invest on moisturizers with higher SPF even though they are generally more expensive. In the long run, I'm sparing my skin and my pockets from ruin -- physical (dark spots, sun spots, wrinkles) and financial (extra cash needed for treatments).
wow I have neverreallythought on adding the spf numbers, that's a Valid question alright, Thank you for this very informative post' myspf protection only comes from my bb cream-SNOE! st has SPF 30.
I've read this kind of dilemma before in Cosmo mag. Yup, it's true layering your SPF one after the other wont guarantee you perfect sun protection the higher SPF you put on will be the exact amount protection you will get no more no less. For instance if you put on SPF15 then followed by SPF30 thereafter SPF30 is your total sunscreen protection; layering SPF is not really possible since it will only clog your pores.
VERY TRUE! Most people would rely only on one type of sunscreen product then apply it quite thinly because of the heavily feeling of a liberal amount which defeats the purpose of putting on sunscreen anyway. It might be a good idea to use a sunscreen with a broad spectrum chemical active such as stabilized avobenzone if one doesn't like the white-cast and heavy feeling of mineral-based sunscreens (although mineral sunscreens are very gentle and tend to protect from a larger portion of the UV spectrum). What's important talaga is re-application:D And as you said, layering products with spf absolutely nets you more protection regardless of spf number. What's important naman is it's broad spectrum, and a good addition to the formula would be antioxidants. Topical green tea, Vitamin C and E are some ingredients known to boost sunscreen effects. In my experience, I prefer zinc-oxide based sunscreens because I'm pale anyway<3 I just always make it a point to set it with translucent powder so I'm not a sticky occlussive-feeling ghost monster:D Nice post Liz! My type of topic<3
Thanks Ms. Liz!
I read that in a yahoo article before. I never knew that even though the product has a high spf, the amount you put on still matters. Another new discovery.
I usually wear BB creams with high spf for lazy days (which is everyday). But when my skin started to break out, I needed longer wear and more coverage. Thus, I moved to foundations. That is when I needed to use the Tony Moly sun base. That become my everyday routine. But I did purchase the soothing cushion from Laneige. It just breaks my heart a little when I see it nearly empty. I got to say, it is the best medium to full coverage, long wearing with good shade match (looks natural), light weight, does not give a white cast and flashback in photos, face product that I have ever tried. A real life saver when my face was suddenly plagued with acne and acne scars.
I always thought that the minimum spf is 30 for outdoors. Didn’t know 15 is good enough. Imma stick to 50 to be safe. The derma told my dad, if you use products with AHA or glycolic acids, use sunblocks with spf 110. Maybe what he's trying to say it that you need higher spf if you're going through all that treatment and make sure, you really stay away from the sun.
I'm currently using Hawaiian Tropics SPF 50 sunscreen for my face. It's not sticky and heavy at all. But I used to use a rather sticky sunblock, and I didn't mind using a teaspoon on my face; I'd rather endure a few minutes of stickiness (and white cast on photos) than suffer skin cancer and premature wrinkles!
I didn't care about putting spf on face until I turned 28. I now understand why we need to put sun protection. I should have started wearing sunscreen even before especially on the face. This Q and A is very helpful. Thanks.
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Wow, Thanks for clearing this is, it now totally makes sense! haha I am currently using a bb cream that has ans SPF 15 in it, is that enough to protect my skin from UV rays? or should I mix it with higher ones?
Hi Liz! Do you know of any BB cream or sunblock that's has oil control too? I have extremely oily skin
Thank you ate for taking the time to ask a derma and to research about this topic! I'm turining 22 this year and I've been mindful that I should start putting sunscreen kasi hindi na nga ako bumabata. Buti nalang ngayon I can have the knowledge to choose a better product to suit my need. :) Thanks ate!
I think aside from not scrimping on the SPF, it's important to remember to re-apply sunscreen every 2-3 hours. Irregardless of how much of an SPF you initially apply, its effectiveness wears off through out the day.
This is a very interesting post for me :) Very nice insights from both the blogger and commenters.
While I am not a dermatologist, I am a skin care enthusiast. When it comes to sunblocks, the most misunderstood concept is SPF.
SPF refers to protection against UVB rays, which cause sunburns and tans. While SPF numbers are important, the hype is quite overrated for me. There's no SPF number that completely protects you 100%. I can better explain this by using math:
Formula: 1 - (1/SPF number) = % protection against UVB rays
Examples:
If SPF rating is 25
1 - 1/25 = 1 - 0.04 = 0.96 or 96% protection against UVB rays
If SPF rating is 50
1 - 1/50 = 1 - 0.02 = 0.98 or 98% protection against UVB rays
What I'm trying to say is that while SPF counts, it's not the only factor to consider in sunblocks. One must check UVA ray protection. UVA damage causes skin aging. To check for UVA protection, look for PA rating. Highest is PA+++.
The protection is greater, but not much. The lasting power of sun protection can very from skin type, and the kind of exposure (sweat, water, or even rubbing off the product). I do agree that the amount applied and reapplication is key. Years back, during a vacation with family, I was using SPF 30 sunblock while my cousins were using SPF 70. After swimming in the morning, I reapplied mid-day while my cousins did not. Lo and behold, my cousins turned red and got burned, while I tanned a bit, but no sign of redness.
P.S. Not sure if it's just me, but whenever I try to post a comment, it doesn't show up :( This is already my 3rd attempt to create a comment on this blog entry.
@zinfandel I have yet too encounter a BB cream that claims to have oil control properties but so far the BB creams that i tried that fare better for oily skin are the etude precious sun bb cream, tony moly expert hyaluronic Bb cream, face shop power perfection bb cream, baviphat magic girls #1 for oily combination BB cream, laneige soothing cushion BB cream. These all have spf of at least 30, with the etude and laneige at spf 50. i also have very oily skin, my T zone is a greaseball area. My skin still gets oily with these bb creams but last longer without blotting almost double in length as compared to other BB creams.
For sunblock, the Tony Moly UV sunset sunblock cream and sun base with both spf 50 are also very compatible with oily combination skin. With other sunblock, i tend to be oily faster, almost after an hour.
I also use the face shop oil cut pore balm under BB cream and foundations if I wants to do away with blotting much longer. The body shop tea tree pore minimiser also has reviews showing it prolongs appearance of oil but I have yet to try this one.
If you are in your 20's , get products with spf and starting to be conscientious earlier will help your skin later on. I wish I paid more attention to skincare when I was younger
I also read that you add up the total SPF you got on your face divided by the number of products with SPF on your face and that's the SPF you actually have.
Nakakaconfuse!
Basta go high like 50 nalang talaga and apply every 2 hours or so.
Thanks for this, Liz! It crossed my mind when I was wearing a tinted moisturizer with SPF 15 and a sunblock with SPF 30. Now, I can finally put that debate inside my head to rest.hehe I also love the sunblock from Neutrogena! I actually wrote about it in my blog. http://geekygirlylife.com/skincare/sunblock-the-most-important-cosmetic-in-your-kikay-kit/. Anyone familiar with Samantha Sotto? She's a Filipina who wrote the novel Before Ever After. When I met her for the first time, I noticed that she has really great skin. Later, she told me that she actually "swears by sunblock". :)
The concept of sun protection has always fascinated me. This post is very insightful, from the blog post to the comments. However, there are a few misconceptions about SPF that have not been covered here.
There's more to sun protection than just SPF.
SPF refers to UVB ray protection, which causes sunburns and tans. The degree of protection does increase as the SPF number is higher (but not by adding SPF of two products together), but not by much. I will explain by using math.
Formula: 1 - 1/SPF = % protection against UVB rays.
If a product contains SPF 25
1 - 1/25 = 1 - 0.04 = 0.96 or 96% UVB ray protection
If a product contains SPF 50
1 - 1/50 = 1 - 0.02 = 0.98 or 98% UVB ray protection
Very little difference in SPF 25 and 50 protection. There's no product that completely protects you from UVB rays as well. The lasting power of sunblock can vary. It can wash off after bathing or swimming, wiping or rubbing off with a towel. or even sweat.
How about UVA rays, which cause skin aging? Check PA rating. The highest is PA+++. A lot of previous comments have pointed out the importance of broad spectrum protection, and not just the value of SPF.
Reapplication is key. During a trip to Coron with relatives, I was using SPF 30 sunblock while my cousins were using SPF 70. After swimming in the morning, I reapplied mid day while my cousins did not. Lo and behold, their skin turned red from sunburn while I did not.
What I'm trying to say is that SPF is important, but often misunderstood. It's not the only factor you should consider in sun care products. Take note of broad spectrum protection as well.
Hi Crissy, thanks for the expounded details on sun protection for the skin. They're all interesting and helpful.
Crissy makes a good point! That's why ridiculously high spf ratings add quite trivial UVB protection with the chance of being more sensitizing due to the higher amount of sunscreen actives and stabilizers. Add to that, a lot of people tend to think that since a high spf sunscreen was applied there won't be a need for re-application. Unfortunately sunscreen actives break down in the presence of sunlight and heavy sweating. Avoiding the sun at peak-hours and re-application of a broad-spectrum sunscreen is absolutely a must for the preservation of your beauty and health<3 Just find the right formulation for you! Sorry, I'm just addicted to this topic:D