For the price and effects you get this stuff is great and Ive tried several of them. This is ester c which is supposed to be the best, encourages collagen production. It is by far the least expensive of the ones Ive looked at, and I looked at many.
ASCORBYL PALMITATE VITAMIN C CAUSES CATASTROPHIC SKIN CELL DEATH AFTER EXPOSURE TO SUNLIGHT. A landmark study reported in the Journal of Investigative Dermatology investigated what happens in human skin when ascorbyl palmitate is applied and then exposed to a moderate amount of sunlight – about the same as an average person would be exposed to on a sunny day. The researchers expected ascorbyl palmitate to penetrate the lipid barrier of the skin, but they weren’t sure if it would penetrate the lipid barrier of skin cells. They discovered that it efficiently penetrates both lipid barriers, and that the ascorbic acid very effectively subdued intra-cellular free radical generation. However they were astonished to find out that any gains bought by the ascorbic acid were dramatically outweighed by the pitfalls of the palmitic acid. Their astonishment was apparent in the choice of adjectives they used to describe the havoc. According to the authors, palmitic acid is a lightning rod for UV rays which brought on “catastrophic” skin cell death on a “massive scale.” The authors further warned against using any vitamin C serum with a concentration of ascorbyl palmitate in excess of 100-300 M (micromoles). Distressingly, many cosmetics contain concentrations as high as 15 percent which exceeds the authors’ warning dose by a factor of 1000. The number of cosmetics containing ascorbyl palmitate exceeded 617 in the year 2000, a leap from a year 1992 count of 667 products (Burnnet 2011).