On the combination of glycolic acid and azelaic acid
If you want to know whether glycolic acid and azelaic acid can be used in combination, you must investigate its properties, observe its effect, and consider practice to understand.

Glycolic acid belongs to α-hydroxy acid and is active. Its molecules are small and can quickly penetrate the stratum corneum of the skin, weaken the adhesion of keratinocytes, cause the old waste keratin to fall off, and the skin is smooth and delicate. And it can promote the synthesis of collagen in the dermis, increase skin elasticity, and reduce the generation of wrinkles.

Azelaic acid is not the case. It originates from nature and has multiple effects on the skin. It can inhibit excessive keratinization of the hair follicle mouth, pass through the hair follicle mouth, and prevent acne formation. It can also reduce free fatty acids on the surface of the skin and regulate oil secretion. It is more antibacterial and anti-inflammatory, and has the ability to inhibit Propionibacterium acne.

As for whether the two can be compatible, it should be explored in detail. From a chemical point of view, glycolic acid is acidic, and azelaic acid is also an acidic substance. If the two are mixed, if there is no chemical reaction that causes damage or adverse reactions, they may be used together. However, the skin is delicate, although chemically feasible, skin tolerance needs to be taken into account.

In practice, there are those who apply the mixture of the two to the skin. When first used, some people feel slightly prickly and reddish skin, which is a sign of skin adaptation. After a little time, if the frequency and concentration of use are gradually increased, many users report that the skin condition improves. Acne fades away, skin tone is even, and skin texture is also good.

So in summary, glycolic acid and azelaic acid can be used in combination. When using it, it is recommended to test it on a small area of skin to see if it has allergies and discomfort. And the starting concentration should be low and gradually increased to achieve the best skin care effect and keep the skin healthy.