Saranghae's Vitamin C is currently concentrated at 23.5% (future concentrations will most likely be higher) and is generally considered an “active concentrate” on the higher end.

You may see topical vitamin C as high as 30% in the near future, but currently, anything over 20% is considered fairly high and effective for various skin conditions.  Topical vitamin C at 20%+ can be used every day and without pause but with a caveat. It depends on how your skin responds to it.

It’s pretty simple, if you see benefits and no skin irritation, you can keep using it with no set end date. If you do see that efficacy is waning and/or you’re skin is starting to experience some irritation, you can take a break (2 to 3 weeks should be enough).

Current clinical data suggests you may experience some sensitivity to UV light over time but this can be easily remedied by consistent application of sunscreen. This is one reason why we suggest starting Vitamin C application at night and then moving to night/day only when you’re certain how your skin reacts to topical Vitamin C.

What About Other Acids?

Acids have been used for skincare for centuries in almost all historical cultures.  Why?  Because it works.
Cleopatra and the ancient egyptians exfoliated their skin with lactic acid from milk and European women have been using stale wine (tartic and malic acid) to rinse their skin.   Most acid we use today are still derived from natural sources and they address skin concerns like acne, pigmentation, visible signs of aging, clogged pores and skin cell turnover.

Examples of acids currently in skincare products:
- salycylic acid
- ascrobic acid
- lactic acid
- glycolic acid
- ferulic acid
- poly hydroxy acid
- hyaluronic acid

These acids are mild and can be used in regular intevals depending on your skin type, skin concern and tolerance for these acids.

There is no one size fits all answer, you’re just going to have to try them and decide for yourself.

You can rest assured that there no major side effects with these skincare acids except a greater sensitive to UV light (meaing you may burn your skin easier) but applying sunscreen and simply taking a breaking from the acids for a little bit of time will solve this issue.