What is a drug target?

How it works

A drug works by acting on something specific in the body. That something is its target. The Open Targets Platform is a freely available tool for finding and ranking potential targets. It defines a target as any naturally occurring molecule that a medicinal product can act on. Its catalog includes RNAs as well as protein-coding genes. It notes that some real targets are protein complexes or the products of fused genes, which its definition does not yet cover.

How many targets there are

A January 2017 analysis in Nature Reviews Drug Discovery covered 1,578 drugs approved by the U.S. Food and Drug Administration (FDA). It mapped these to 893 human and pathogen biomolecules, 667 of them human proteins. A September 2026 review in the same journal counted 686 biomolecules modulated by 1,702 drugs. The two tallies may not be directly comparable. In the full text of the earlier paper, the authors cautioned that assigning targets is often not clear-cut, for example when a drug binds several closely related proteins.

Many possible targets have no approved drug. An archived, undated National Institutes of Health program page cites an estimate that as many as 4,000 proteins could be targeted by drugs. It says FDA-approved drugs act on only 5% to 10% of that "druggable" set. It names ion channels, G-protein-coupled receptors and protein kinases as well-established target families.

Why the choice matters

Only about 10% of clinical programs end in approval, an April 2024 analysis in Nature says. It cites earlier studies for the figure. Its authors estimated that drug mechanisms backed by human genetic evidence were 2.6 times more likely to succeed than those without it. They described human genetics as an important way to find and rank candidate targets.

Where things stand in 2026

AI tools are being used to propose targets as well as molecules. The authors of a Phase 2a trial published in Nature Medicine in June 2025 described the drug rentosertib as an AI-generated inhibitor of TNIK. They said TNIK, a target in the lung disease idiopathic pulmonary fibrosis, was discovered using generative AI. Insilico Medicine sponsored the trial and employs several of the authors. The authors called for larger, longer trials.

A Perspective in Nature Reviews Drug Discovery in August 2026 said evidence that AI methods have had clinically relevant impact on drug discovery was, so far, limited.