In the first century AD, Pliny used willow bark (as a source of SA) to treat calluses and corns. Buchner, Brugnatelle, and Fontana isolated salicin from willow bark in the late 1820s, which was later refined by Leroux. The ability of salicylic acid to soften and exfoliate the stratum corneum was discovered in the 1860s.
Rich in Salicylic Acid.
KERATOLYTIC PROPERTIES
Salicylic acid has keratolytic properties. Being a lipophilic agent, salicylic acid removes intercellular lipids, which are linked covalently to the cornified envelop surrounding the surface epithelial cells due to its antihyperplastic effect. It decreases the adhesion of corneocytes and causes loosening of these cells and their subsequent detachment.
It causes microexfoliation of the superficial layers of the skin to unclog blocked sebaceous follicles, leading to removal of superficial lesions followed by regeneration of new epidermal and dermal tissues.
Therefore, salicylic acid causes the loss of cornified cells followed by activation of the epidermal basal cells and underling fibroblast. It promotes skin rejuvenation leading to smoothing of the skin and improvement of its surface texture.
COMEDOLYTIC PROPERTIES
Salicylic acid is an anti-seborrheic active ingredient. Being a lipophilic agent and having an ability to concentrate in the pilosebaceous apparatus, salicylic acid regulates sebum production and secretion in patients with acne.
Salicylic acid decreased sebocyte lipogenesis by downregulating the adenosine monophosphate-activated protein kinase (AMPK)/sterol response element-binding protein-1 (SREBP-1) pathway and reduced inflammation by suppressing the NF-kB pathway in these cells. In addition, salicylic acid decreased the cell viability of sebocytes by increasing apoptosis via the death signal receptor pathway.
When formulated to be non-irritation and non-sensitizing based on the quantitative risk assessment, salicylic acid is safe to be used in cosmetics based on the concentration specified in this safety assessment.
https://online.personalcarecouncil.org/ctfa-static/online/lists/cir-pdfs/FR766.pdf