Starter Retinol
*4-week clinical study on 30 participants
** 12-week consumer study of 130 participants
*** Based on a 4-week In Vitro study
Advanced Retinal
*8-week clinical study of 26 participants
** 8-week consumer trial of 105 participants
*** G. Siegenthaler et al., Retinol and retinal metabolism, Biochemical Journal, 1990, 268, pp 371-378