better than glutathione vs Vitamin C: Which Is for Skin Glowing? Glutathione vs. Other Antioxidants: What
Description
Theres no official frequency guideline

Universal Skin Compatibility: Formulated for all skin types and suitable for all age groups

Congestion and hepatocellular injury can be observed after PQ accumulation in the liver (Matsumori et al., 1984)

Research Evidence: advantage goes to GHK-Cu

This unique formula visibly rejuvenates the skins ability to renew and disrupts discolouration without causing post-inflammatory hyperpigmentation on deeper skin tones
O., Wolf M