2024 Book of Answers 1. How should skin care ingredients be matched with niacinamide + retinol (A alcohol).
Whitening combination, the combination of the two has a 1+1>2 effect, and retinol has accelerated metabolism.
Niacinamide has the effect of blocking the transmission of melanin to the epidermal skin.
VC+VE are both antioxidants that work together to prevent aging and help replenish and repair cells.
Retinol + hyaluronic acid.
Hyaluronic acid hydrates and squalane forms a natural barrier on the skin's surface, and the two work together to lock in moisture.
Squalane + salicylic acid.
Acids and restorative moisturizing ingredients can relieve irritation and promote absorption.
Va + ceramides.
VA can regulate the metabolism of the stratum corneum, plus the function of ceryl moisturizing, to achieve enhanced removal of fine lines and anti-aging.
The role of the old. 2. Minefield of skin care product ingredient matching.
Nicotinamide X high concentration of VC
Both belong to the higher the concentration, the stronger the irritation, so it should be staggered, such as morning C and evening A
Nicotinamide X acid.
It is not recommended to use them together, both of which have a certain irritation and cause a redness reaction.
Retinol x high concentration acid.
Using both at the same time will destroy the pH level of the skin, as acids have a strong keratin peel.
Drop effect, and all have a certain irritation, ** is very likely to be intolerant, resulting in a barrier.
Damaged. 
Alcohol x protein.
Alcohol can completely render skincare products that contain protein ineffective.