Table 7.

Effect and mechanism of nucleic acid related to skin aging.

Source	Substance	Dosage	Role	Mechanism	References
Exogenous and endogenous	Nucleic acids and their derivatives	100 nm	Repair damaged DNA, protect skin	Cell self-repair ability ↑, activity of nucleic acid repair enzymes ↑	[96,97]
Exogenous and endogenous	Small RNAs (e.g., microRNA)		Regulates the skin cell life cycle	Regulating gene expression, synthesis of collagen and elastin ↓	[98,99]
Exogenous and endogenous	Nucleotides and nucleosides	1 micromole to 50 micromole	Improves cell metabolism	As a cellular energy and signaling molecule, it maintains the vitality of skin cells	[100]
Exogenous	Exogenous nucleotides and nucleosides		Skin cell proliferation, differentiation and immune regulation	It acts on purine receptors and activates signaling pathways related to skin cell proliferation, differentiation, and immune regulation	[101]

↑, increase; ↓, decrease.