does SPF "add up"?
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free skin care · Sat Jun 26, 2004 10:45 am

for example, if u wear a moisterizer with spf 30 and powder with spf 15 it doesnt add to spf 45 does it?

free skin care · Sat Jun 26, 2004 11:08 am

Nope! It divides it! so you will be wearing the equivalent of 22.3 SPF
bummer innit!

free skin care · Sat Jun 26, 2004 1:16 pm

wow that sux Confused

free skin care · Sat Jun 26, 2004 1:20 pm

I spose so, but then an SPF of 20+ is pretty good Smile

free skin care · Sat Jun 26, 2004 10:32 pm

Not only that 2 spfs don't add up, certain active ingredients destabilizes each other (ie octinoxate destablizes avobenzone). So you really have to research your ingredients if you want to mix spfs.

free skin care · Sun Jun 27, 2004 2:33 am

OMG! it gets worse! Shock

Sun Jun 27, 2004 4:28 am

I'm not sure about it halving (Guapagirl - what is the theory behind that?) but I do know for certain that they do NOT add up. Best case scenario would be that you would get protection equivalent to the higher SPF product you are using.

Mabsy

free skin care · Sun Jun 27, 2004 7:40 am

Mabsy, I read it in a magazine last year. I have looked and can't find anything anywhere about mixing spfs which is odd. Am sticking this handbag link in which has an exaustive breakdown on the mechanics behind sun protection (chillipadi is considered an 'expert' there on all things solar Smile

) and will PM chillipadi to see if she knows anything. Don't bother with all 15 pages unless you want info on particular products, the main info is in 1st post. It's a bit boring but very informative

http://forums.handbag.com/showthread.php?s=&threadid=151113&perpage=10&pagenumber=1

Mon Jun 28, 2004 5:47 am

Thanks for the link Guapagirl. I've been meaning to check out handbag.com - now's as good a time as any Smile

Mabsy

free skin care · Mon Jun 28, 2004 7:02 am

, makes you think, you have a moisturiser which says 20spf, then a foundation that says spf8/15/20 you think you'd be safe. Embarassed

Perhaps is isn't stable if you use regular foundations, since Bare Essenctuals is powder, do we think this is a good option. I'm currently using summer bisque as a foundation rather than a concealer Smile

free skin care · Mon Jun 28, 2004 11:43 am

Mabsy wrote:

Thanks for the link Guapagirl. I've been meaning to check out handbag.com - now's as good a time as any Smile

Mabsy

It will end up costing you if you get hooked! Laughing

That said, there are some quite unpleasant threads sometimes and there seem to be loads of kids on these days, hence my now permenant defection to EDS! Very Happy

However, I PM chillipadi (who is really nice) and asked her about mixing spf's and she reckoned that a final spf would be between the two original ones. She didn't say why or where she got the info, but she is pretty knowledgable about this stuff. I actually tried to lure her here, but don't know if she will!

free skin care · Mon Jun 28, 2004 1:58 pm

Hello ladies and gents! Smile

I'm in the U.S. and I've read somewhere in one of the plethora of fitness and fashion magazines that I "veg" out/wind down with that SPFs don't "mix" nor do they combine.

Since you are applying it in layers, the first layer is the SPF protection that you benefit from. The others don't add to it. I'm not sure about negating it though.

I've also read recently that Duke University did a study on SPFs. If you use a C+E serum that it doubles the protection factor of the SPF you have over the serums.

My two U.S. cents. Please jump in and correct me if I'm wrong.

HTH

free skin care · Mon Jun 28, 2004 9:34 pm

No, they certainly do not add up. I read that you only get the highest SPF that you apply. Also, some sunscreen ingredients destablize each other.

free skin care · Tue Jun 29, 2004 1:39 am

There are lots of articles on the radio etc on spfs here in the uk at the mo, the general opinion in the uk has been the mixing spfs is a no-no, and that to assume you are "diluting" products and leaving you less protected. There is concern about the increase of skin cancer over the last few years as people assume they are more protected wearing sun products and stay out in the sun longer. Not sure how this figures as many cases are believed to have been linked to having been burnt on occasions from years past. Its all so confusing, and working in a doctors surgery we still see people with sunburn and most often when weather has been cloudier and not so hot. The message does need to be got across that the suns rays are harmful anytime.

Tue Jun 29, 2004 5:47 am

I have to say that the rest of the ladies out there are right: they don't add-up when layering. Did you know that between an SPF 15 and 30, that there is only a 4% margin of protection? Yup. And anything beyond an SPF 30 is just additional ingredients that may cause more irritation to the skin.

free skin care · Tue Jun 29, 2004 9:34 am

wow i didnt know that thanks for all the replies Smile

Tue Jun 29, 2004 11:56 am

Wow! I didn't realize certain products can destablize other products. I was using a tinted moisturizer SPF 15 with physical blockers like zinc and titanium oxide I believe. And I just purchased Murad's essential C eye cream SPF 15 which has the chemical blockers in it. I've been putting the Murad on first and then the tinted moisturizer. I wonder if this is a problem??

Also, I recently heard (after I ordered the Murad cream) that the chemical blockers are not as effective as the physical blockers (which is why I was doubling up). Anyone hear that? My dermatologist confirmed that. I decided to try the Murad cream anyway since it got so many good reviews on this forum but I'm worried that it alone is not as effective as others.

Anyone know?

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