Abstract
In recent years, microneedles (MNs), an innovative transdermal drug delivery system, have demonstrated significant advantages in treating diverse skin diseases. The stratum corneum (SC), with its 'brick-mortar' structure, is the main barrier to drug penetration into the skin. MNs-including solid, coated, hollow, dissolving, and hydrogel-forming types-penetrate it minimally to form temporary micro-channels, enabling efficient delivery of a wide range of therapeutic agents. These include small molecules, biologics, nanoparticles, and photosensitizers, among others. This technology has been effectively applied in the treatment of androgenetic alopecia, acne, scars, melanoma, psoriasis, atopic dermatitis, and vitiligo. By avoiding stimulation of dermal blood vessels and nerves, MNs offer low pain and high patient compliance. These advantages underscore their broad clinical potential for dermatologic therapy. Future studies must optimize material selection, drug-carrying efficiency, and scale-up production to facilitate clinical translation.