Does glycolic acid cause spots to appear?

Yes, it can happen that the application of a glycolic acid treatment may cause spots to appear, but this does not mean that its use should be discontinued, quite the opposite!

When regularly applying a treatment containing active ingredients that boost cellular renewal, such as glycolic acid, the microcomedones that are forming will all emerge a few days later. This phenomenon is referred to as "the purge".

As a reminder, a natural cycle of skin cell renewal lasts approximately 28 days but this can vary greatly depending on the individual, ranging from 3 weeks to 8 weeks! During this cycle, new cells are born at the level of the basal layer, which is the deepest layer of the epidermis. As the cycle progresses, these cells migrate to the surface of the skin. During this process, they lose their nuclei and transform into dead cells. They then form the horny layer, the most superficial layer of the epidermis. The dead cells or keratinocytes are then shed (either naturally, or through chemical or mechanical exfoliation) and a new cell cycle begins.

28 days is therefore the average time it takes for the skin to regenerate. However, when this time lengthens, dead cells accumulate on the skin's surface and clog the pores. If this is combined with hyperseborrhea (overproduction of sebum), we can then see the appearance of tiny comedones. These can either disappear on their own or evolve into whiteheads, blackheads, papules or pustules. The formation time of a microcomedone is directly correlated to the time it takes for the skin to naturally exfoliate, which is on average 28 days as previously explained. By accelerating this exfoliation time, glycolic acid therefore speeds up the formation rate of microcomedones which "resurface" more quickly but also take less time to disappear. Furthermore, glycolic acid prevents the clogging of pores and thus the appearance of future microcomedones.