Effects when administered locally:

• Positive effect of vitamin B3 on the facial skin overall appearance :Bissett DL, Oblong JE, -Berge CA. Niacinamide : A B vitamin that improves aging facial skin appearance. Dermatol Surg. 2005 Jul;31(7 Pt 2):860-5.
• Positive effect of arginine on cutaneous ageing (as well on eczema): Topically applied arginine hydrochloride. Effect on urea content of stratum corneum and skin hydration in atopic eczema and skin aging Hautarzt. 2004 Jan;55(1):58-64.
• Role of hydroxyproline on collagen synthesis: I.Kelman Cohen and R.F. Dieglmann ; Effect of hydroxyproline (oxacéprol) on collagen synthesis. Experimental and molecular pathology,28,38-64.1978.
• Positive effect of vitamin A (retinol) associated to hydroquinon on cutaneous protection in regards to the sun (hydroquinon is not authorized in France at this proporation , that is why it is not a Skin Progress' content) Novel approach to the treatment of hyperpigmented photodamaged skin: 4% hydroquinone/0.3% retinol versus tretinoin 0.05% emollient cream. Dermatol Surg. 2005 Jul;31(7 Pt 2):799-804.
• Positive effect of green tea polyphenols locally applied on cutaneous ageing inducted by solar rays: Chiu AE et al. Double-blinded, placebo-controlled trial of green tea extracts in the clinical and histologic appearance of photoaging skin. Dermatol Surg. 2005 Jul;31 (7 Pt 2):855-60.
• Postive effect of arginine on skin ageing (as well as eczema) Nenoff P, Donaubauer K, Arndt T, Haustein UF. Topically applied arginine hydrochloride. Effect on urea content of stratum corneum and skin hydration in atopic eczema and skin ageing Hautarzt. 2004 Jan;55(1):58-64.
• Role of hydroxyproline on collagen synthesis:I.Kelman Cohen and R.F. Dieglmann ; Effect of hydroxyproline (oxacéprol) on collagene synthesis. Experimental and molecular pathology,28,38-64.1978.