Spf or sun protection factor, is the amount of increased protection a sunscreen provides. If you are like most people, you will begin burning after 15 minutes without protection. An SPF helps protect against sunburn, and does not "stop" the tanning process completely!!! It's the burning that you want to omit, that is what causes skin damage! it's not the tan!!!!!!!!!!!!!!! Determine your protected sunning time by multiplying the SPF number by the amount of time it normally takes you to show signs of burning if unprotected. For example: Spf 8: 8 x 15 = 2 hours of increased protection. Spf 15: 15 x 15 = 3 3/4 hours protection. If you burn in 5 minutes (usually very sensitive skin) with an spf 15: 15 x 5 = l h 15 increased protection. Most common sunscreen ingredients are: titanium dioxide, zinc oxide and avobenzone (also called parsol 1789) and butyl methoxydibenzoylmethane. Avobenzone (also called Parsol) is less pore clogging than titanium dioxide and zinc oxide, but some people do experience irritation (rash or little red bumps) from avobenzone. Titanium Dioxide and Zinc oxide are natural products but can be more pore clogging as they sit on the skin's surface and deflect back the UV rays, rather than absorbing into the dead layer of the epidermis. A combination of Avobenzone and titanium dioxide or zinc oxide may be less clogging then td or zinc alone for some people. But in the end they all block the pores to a certain degree because of there texture. Remember the lesser the spf in your cream or lotion the less chances your skin will react!! for example an spf 8 in your cream will give you minimal to no skin irritations or pore clogging!!! So it comes down to choose what works or is best for your skin or what you feel more comfortable with! spf 2 blocks: 50% spf 8 blocks: 86% spf 15 blocks: 92% spf 30 blocks: 96% Spf 8-15: Is sufficient to give your skin ideal protection against the harmful effects of light for normal exposure to the sun like at home, at the office, in the city, day to day errands,. but the more sun you are exposed to (an entire day at the beach, for instance) the higher the SPF should be to give your skin optimal protection. Sunscreen: Is usually a cream or lotion. It is a chemical protective product works by absorbing a minimal amount of the uv rays and filtering them. Many people have allergic reactions to the chemicals in sunscreen seen as a rash... Sunblock: Is usually an opaque cream or paste. Provides a physical block that functions by reflecting rays. sunblocks contain natural minerals. Sunblock protects you by reflecting the uv rays before they penetrate your skin. Makeup with spf in it do not offer enough protection against the sun you are better to skip those entirely and splurge on a good moisturizer with sunscreen or a sunblock. One should never go to bed with sunscreen on your face, not to mention all the chemicals that will sit there causing irritation and blocking your pores. At night your skin heals and renews itself taking in nutrients from the air and your treatment creams. The skin's optimal renewal action takes place between the hours of 10 p.m. and 2:00 a.m. this is a time to nourish the skin not block the pores...... Please wash off your sunscreens as soon as you can. Again I stress my view on spfs use - apply them when you need them do not abuse there use...... they are meant to be used when you are outside.... When you need protection from the sun especially during summer time, or whenever you are out in the open, for day to day use in the summer while doing errands, in and out of the home/car all day then an SPF 8 to 15 is sufficient... You can apply 30 when you will be outside for a longer period of time. In my opinion high spf lotions are not to be used daily all year round if you are not working outside or if you will be inside most of the day..... If you really feel the need to wear a cream with spf daily stick with the ones that have a low spf... like an spf 8 and use an spf of 30 on areas (spot treat) where you need extra protection such as discolorations spots..... In my opinion if you are inside most of the day you do not need a cream with an spf in it!!! Best protection is to wear a hat whenever possible and stay out of the sun during the peak hours of 10/11 a.m. - 3/4 p.m. Note: If you have pigmentation spots (discoloration) and are worried about them you can spot treat them with an spf 15-30 if you wish!!! instead of putting an high spf all over the face. Did you know that Vitamin C,Shea Butter, Aloe Vera, Carrot Oil and Vitamin E help support the skin's natural defences against uva/uvb! Vitamin E protects the cells against the adverse effect of free radicals, it protects skin during sun exposure! Many studies have shown that antioxidants may be a very important strategy for preventing skin cancer.! Aloe Vera was used 1000s of years ago as an essential protection against the rays of the sun.! If you will be spending time out in the sun please always apply a sun block/sunscreen over your serums or creams containg vitamin A or C.!!!!!!!!!! My tips for this summer!! - First time you go out in the sun, go for no longer then 30 minutes - fairer skin less time and find a shade place you can go too after the initial 30 minutes then increase gradually through the summer always protecting the skin! - Go out between the times of 9-11 am and after 3-4 p.m. - Prepare the skin properly and treat the skin after being out in the sun! To prepare the skin properly apply your moisturiser under your sunscreen or sunblock, the layers help to protect the skin! After your time in the sun wash off your sunscreen or sunblock and apply a moisturiser or product designed for after sun!! Please try and stay away from tanning beds, in my opinion they are not safe for your skin!