From the Journal of The National Cancer Institute:
According to Weinstock, the cap on SPF labeling is not a major issue for the public as a whole. "I think that if the general public uses SPF 30 or greater, that's sufficient." As Weinstock explained, SPF is a reciprocal function: SPF 15 lets in 1/15 of the burning rays; SPF 30 lets in 1/30; and SPF 50 lets in 1/50. Therefore, the difference between SPF 30 and SPF 50 is only a difference of 97% effectiveness versus 98% effectiveness. "That little bit may be important to some people who have particular sensitivity," said Weinstock. "But, to the general public, it really is not that critical."
Remember that SPF30+ sun cream will block out 97% of the sun's rays. SPF50+ will block out 98%. There is NO bearing on the DURATION you can put the sun screen on and expect protection.
The issue is that people generally don't put on enough, so they're only getting around 50% protection because of their own vanity. The more you put on, the closer you get to the full coverage offered by the cream. If you use an SPF30+ cream you'll only get a little less protection than the 50, but you need to use enough. The SPF isn't the issue, it's the usage.
spf 30 is for lighter skin
No. SPF 30 lets in 1/30 of burning UV rays, while SPF 50 lets in 1/50. Adding the two together is pointless and would not result in high levels of skin protection.
It was probably SPF 30 because that blocks 96.7% of UVB rays. SPF 50 blocks 98% so you aren't really getting that much more protection than the SPF 30. Neutrogena has a SPF 100 but it really isn't necessary because as I said, SPF 30 is already blocking a significant amount, and SPF 50 doesn't even make that much more of a difference. Just for your information, SPF 100 blocks 99% of UVB rays so it REALLY doesn't do much more than SPF 50.
Probably 5, 10, 15, 20, 25, 30, 35, 40, 25, and 50. Why do they would make lotion like SPF 5 and 10 while they already have SPF 50?
100, because it offers more UV protection.
You should wear at least an SPF level of 30 to prevent from being burned. You will also need to reapply as needed throughout the day to maintain the same level of protection.
SPF 50 stands for Sun Protection Factor 50, so if the normal time to get burnt is 20 minutes you will be safe for 50 times that.
It has been recommended my medical experts that you should apply sun-screen with a minimum Sun Protection Factor (SPF) of 30. SPF 30 means it can protect you 30 times better than if you didn't have it. Remember that even if you have sunscreen on, you can still get sunburnt. The best sun protection is still shade. Avoid the sun during 11am and 2pm where the sun is most intense.
An SPF of about 30
Neutrogena makes a spf 30 lipgloss.
It is proven that people with light skins, are best protected when using a SPF 50 sunscreen and upwards. Sunscreen has SPF ranging from 8, all the way up to 70. Depending on your skin tone, it is better to be too careful by protecting with a high number SPF.
4, 15, and 30 are good Sun Protection Factors for kids as they contain no "Bad Ingredients". SPF 50+ should not be used on young children. SPF 100+ can not be used on children under 13.
Yes, it is fine. If you have fair skin you can wear an even stronger SPF.