Therefore, it is very important that you wear sunscreen everyday, with an SPF of 30.Of note, after SPF 30, there are decreasing marginal returns in UVB protection. The % of UVB protection as a function of SPF Value is a log graph and plateaus after SPF 30. Therefore, there is not much difference in protection between SPF 40 and 50. Sunscreens with an SPF 100 are banned in some countries.
In women, acne can be improved with the use of any combined birth control pill.[89] These medications contain an estrogen and a progestin.[90] They work by decreasing the production of androgen hormones by the ovaries and by decreasing the free and hence biologically active fractions of androgens, resulting in lowered skin production of sebum and consequently reduced acne severity.[10][91] First-generation progestins such as norethindrone and norgestrel have androgenic properties and can worsen acne.[15] Although oral estrogens can decrease IGF-1 levels in some situations and this might be expected to additionally contribute to improvement in acne symptoms,[92][93] combined birth control pills appear to have no effect on IGF-1 levels in fertile women.[90][94] However, cyproterone acetate-containing birth control pills have been reported to decrease total and free IGF-1 levels.[95] Combinations containing third- or fourth-generation progestins including desogestrel, dienogest, drospirenone, or norgestimate, as well as birth control pills containing cyproterone acetate or chlormadinone acetate, are preferred for women with acne due to their stronger antiandrogenic effects.[96][97][98] Studies have shown a 40 to 70% reduction in acne lesions with combined birth control pills.[91] A 2014 review found that antibiotics by mouth appear to be somewhat more effective than birth control pills at decreasing the number of inflammatory acne lesions at three months.[99] However, the two therapies are approximately equal in efficacy at six months for decreasing the number of inflammatory, non-inflammatory, and total acne lesions.[99] The authors of the analysis suggested that birth control pills may be a preferred first-line acne treatment, over oral antibiotics, in certain women due to similar efficacy at six months and a lack of associated antibiotic resistance.[99]
Diet. Studies indicate that certain dietary factors, including skim milk and carbohydrate-rich foods — such as bread, bagels and chips — may worsen acne. Chocolate has long been suspected of making acne worse. A small study of 14 men with acne showed that eating chocolate was related to a worsening of symptoms. Further study is needed to examine why this happens and whether people with acne would benefit from following specific dietary restrictions.