 Transdermal drug delivery offers several benefits, including improved patient compliance, sustained release, avoidance of gastric irritation, and elimination of pre-systemic first-pass effect. However, only a few medications can be delivered through the transdermal root and therapeutic amounts. Microneedles are used to enhance transdermal drug delivery. There are different types of microneedles, including hollow, solid, dissolving, and hydrogel-forming microneedles. Hydrogel-forming microneedles do not contain drugs, but imbibe interstitial fluid to form continuous conduits between dermal microcirculation and an attached patch type reservoir. Several microneedles approved by regulatory authorities for clinical use are examined, along with concerns and challenges regarding their use. This article was authored by Kevin Eda.