# How many drug targets are there? > ProteinIQ counted 809 molecular targets behind 2,205 approved drugs in ChEMBL 37: 611 in humans and 179 in pathogens. GPCRs carry 22% of those drugs; the often quoted 34% uses a smaller FDA list. Approved drugs act on about 800 molecular targets. In ChEMBL 37, the May 2026 release of the curated drug and bioactivity database run by EMBL-EBI, we counted **809 distinct efficacy targets** behind 2,205 approved drugs. Of those, 611 are human, 179 belong to bacteria, viruses, fungi and parasites, and 19 are molecules with no organism, such as iron for chelating drugs or the anticoagulant dabigatran, which its antidote idarucizumab binds. The spread is uneven. The glucocorticoid receptor alone carries 65 approved drugs, while 285 human targets have exactly one. Most of the targets also come from a handful of protein families, which is why the share of drugs that act on GPCRs has become one of the most quoted and most disputed numbers in pharmacology. ## How many drug targets are there? The count depends on what you call a target. We took every ChEMBL parent molecule with an approved status and a therapeutic use, 2,511 drugs in all, and kept the targets that ChEMBL curators mark as responsible for the drug's effect. That gave 809 targets for the 2,205 drugs with a known one. ChEMBL records a mechanism against the most specific target its evidence supports. Metoprolol acts on one protein, the beta-1 adrenergic receptor. Benzodiazepines act on the GABA-A receptor, which ChEMBL treats as one target although the channel is built from several subunits. Olanzapine is mapped partly to "D2-like dopamine receptors", a family target covering several receptor genes. Table 1. Targets of approved drugs in ChEMBL 37, by organism and kind. Efficacy targets of 2,205 approved therapeutic drugs; each ChEMBL target ID counts once. Family or group includes ChEMBL selectivity groups; complexes include protein-nucleic acid complexes such as the ribosome. Source: ProteinIQ analysis of ChEMBL 37 (2026). Target kindHumanPathogen or parasiteNo organismAll Single protein4281030531 Protein complex5834092 Protein family or group737080 Protein-protein interaction2002 Non-protein target (DNA, RNA, lipid, metal and others)503519104 All targets61117919809 Counted as ChEMBL targets, approved drugs reach 561 human proteins or protein assemblies. Expanded to the individual human proteins behind every complex and family, the same targets cover 984 distinct UniProt entries. Neither figure is wrong; one counts what a drug binds as a unit, the other every gene product involved. The single-protein targets alone come to 428. Of the 179 targets outside humans, 88 are bacterial, 45 viral, 26 belong to parasites such as *Plasmodium* and lice, and 20 to fungi. They are the targets of 390 drugs that act only on a pathogen: 324 small molecules such as antibiotics, antivirals and antifungals, 34 vaccines and 12 antibodies. ### How the count compares with published estimates Published counts land between our two human figures, because each team draws the unit in a different place. The best-known one, from Santos and colleagues, curated 893 targets for 1,578 FDA-approved drugs, 667 of them human proteins, using data retrieved in June 2015. Overington, one of its authors, had counted 324 targets in 2006. Table 2. Published counts of drug targets. Each study used its own definition of approval, target and cutoff date, so the counts are not directly comparable. Sources: Santos and colleagues (2017), Avram and colleagues (2023), Halip and colleagues (2026), ProteinIQ analysis of ChEMBL 37 (2026). StudyDrugs coveredAll targetsHuman protein targets Overington and colleagues (2006), as restated by SantosFDA-approved drugs324Not given Santos and colleagues (2017)1,578 FDA-approved drugs, data from June 2015893667 DrugCentral 2023Human drugs approved to March 31, 2022927704 Halip and colleagues (2026)1,702 drugs686Not given in abstract ProteinIQ, ChEMBL 37 (2026)2,205 approved therapeutic drugs809561 targets, 984 proteins DrugCentral, one of the three databases merged in the Santos map, listed 927 efficacy targets in 2023, 704 of them human proteins and 222 in infectious agents. A 2026 review by the same researchers puts the current total at 686 biomolecules modulated by 1,702 drugs. Our count includes more drugs because ChEMBL treats a drug as approved when a source of approved-drug information lists it, such as the FDA, the European Medicines Agency or the WHO's ATC classification. Many older European drugs, such as betahistine and domperidone, were never approved in the US. ## Which target classes do approved drugs act on? GPCRs are the largest single class: 110 human GPCR targets carry 484 approved drugs, 22% of the drugs with a known target. Enzymes outside the kinase and protease families come second with 19%, and the other well-known families follow well behind: ion channels at 9%, nuclear receptors at 8% and protein kinases at 6%. ![Paired horizontal bars of the share of approved small molecules and biologics acting on each target class; GPCRs and other enzymes lead for small molecules at about 24% each, while biologics act most on GPCRs, other membrane receptors, secreted proteins and non-protein targets](/images/charts/approved-drugs-by-target-class.webp '**Figure 1. Approved drugs acting on each target class.** Share of 1,664 small molecules and 463 biologics with a known efficacy target in ChEMBL 37. A drug counts in every class it acts on. Biologics include peptides and proteins, antibodies, enzymes, vaccines, and cell and gene therapies. Source: [ProteinIQ analysis of ChEMBL 37 (2026)](/data/guides/drug-targets/target-class-summary.csv).') Small molecules and biologics divide the work almost cleanly. Small molecules dominate ion channels, nuclear receptors and transporters, where a binding pocket inside the membrane or the cell suits a compact, drug-like molecule. Biologics act on what sits outside the cell: cytokine and growth factor receptors, secreted proteins such as TNF and the interleukins, and surface antigens such as CD19. None of the 463 biologics acts on a nuclear receptor, and only 3 on a transporter or epigenetic regulator. GPCRs are the one large class both modalities share, but not through antibodies. Of the 74 biologics on GPCRs, 71 are peptides and proteins, most of them modelled on natural hormones, such as semaglutide on the GLP-1 receptor and octreotide on somatostatin receptors. Only three antibodies act on a GPCR: erenumab, mogamulizumab and talquetamab. Table 3. Human targets and approved drugs by target class. Classes follow ChEMBL's protein classification; kinases are protein kinases, including receptor tyrosine kinases. Drug shares use drugs with a known efficacy target as the denominator (1,664 small molecules, 463 biologics and 2,205 drugs in all, including 78 oligonucleotides and mixtures), and a drug counts in every class it acts on. Source: ProteinIQ analysis of ChEMBL 37 (2026). Target classHuman targetsSmall moleculesBiologicsAll drugs GPCRs11024.2%16.0%22.0% Ion channels5011.2%2.8%9.1% Protein kinases825.4%9.3%6.0% Nuclear receptors1810.9%0%8.4% Proteases297.1%6.5%7.0% Other enzymes11624.0%4.1%19.0% Transporters216.0%0.2%4.6% Epigenetic regulators100.5%0.4%0.5% Other membrane receptors320.7%15.1%3.7% Other transcription factors30.2%0%0.1% Secreted proteins330.2%13.4%3.6% Surface antigens90.1%8.4%1.9% Other or unclassified proteins384.7%13.8%6.9% Targets spanning two classes101.6%0.4%1.3% Non-protein targets507.6%14.7%10.2% All human targets611 The table also shows how differently classes are used. Nuclear receptors are few, 18 human targets, but they carry 181 small-molecule drugs, because steroids, retinoids and thyroid hormones were optimized against the same receptors for decades. Kinases are the reverse: 82 human targets with only 133 drugs between them, since 86 of the 90 small-molecule kinase drugs were first approved in 2001 or later, and many kinases still have only one or two. Santos and colleagues reported that GPCRs, ion channels, kinases and nuclear receptors make up 44% of human protein targets and account for 70% of small-molecule drugs. In our count the same four classes make up 43% of human targets and act on 51% of small molecules with a known target, a gap that the next section largely explains. ## What percentage of drugs target GPCRs? About a fifth to a third, depending on the denominator. In our count, **22% of approved drugs with a known target act on at least one GPCR**, and 19% of all approved drugs do. The figure most often repeated, 34%, comes from Hauser and colleagues, who counted 475 drugs at 108 GPCRs, "~34% of all drugs approved by the US Food and Drug Administration". A 2025 analysis by Schröer and Seifert arrived at 19% and argued that 30% is too high. ![Horizontal bars of the share of drugs acting on GPCRs under six denominators, from 27.9% of the top 300 US prescriptions in 2024 down to 13.1% of drugs first approved from 2015 to 2024 and 2% of antibodies](/images/charts/gpcr-share-of-approved-drugs-by-denominator.webp '**Figure 2. Share of drugs acting on GPCRs.** ProteinIQ analysis of ChEMBL 37. Small molecules, drugs with a target, the 2015 to 2024 cohort and antibodies count only drugs with a known efficacy target; all approved drugs includes those without one. US prescriptions weight the 300 most prescribed products of 2024 by their prescription counts. Sources: [ProteinIQ analysis of ChEMBL 37 (2026)](/data/guides/drug-targets/provenance.json), [ClinCalc (2026)](https://clincalc.com/DrugStats/Top300Drugs.aspx).') The numerator barely moves between studies. Hauser counted 475 GPCR drugs, Sriram and Insel about 700 at the generous end, Lorente and colleagues 516 in 2025, and we count 484. What changes is the denominator. Hauser's 475 drugs at 34% imply a list of about 1,400 FDA drugs; ChEMBL's 2,205 drugs from several regulators give 22%; a list of recent approvals gives much less. Table 4. Published and calculated shares of drugs acting on GPCRs. GPCR drugs are drugs with at least one GPCR among their targets, except in Schröer and Seifert, where each drug has one primary target. Sources: Santos and colleagues (2017), Hauser and colleagues (2017), Sriram and Insel (2018), Lorente and colleagues (2025), Schröer and Seifert (2025), ProteinIQ analysis of ChEMBL 37 and ClinCalc (2026). SourcePopulation countedGPCR share Santos and colleagues (2017)FDA small-molecule drugs to June 2015, rhodopsin-like GPCRs only33% Hauser and colleagues (2017)FDA-approved drugs, July 201734% Sriram and Insel (2018)About 1,950 FDA and EMA drugs, November 201725% to 36% Lorente and colleagues (2025)Approved drugs36% Schröer and Seifert (2025)1,110 new active substances approved in Germany, 1987 to 202319% Schröer and Seifert (2025)FDA novel approvals, 2018 to 202314.5% ProteinIQ, ChEMBL 371,664 small molecules with a known target24.2% ProteinIQ, ChEMBL 372,205 drugs with a known target22.0% ProteinIQ, ChEMBL 372,511 approved therapeutic drugs19.3% ProteinIQ, ChEMBL 37464 drugs first approved 2015 to 2024 with a known target13.1% ProteinIQ, ChEMBL 37 and ClinCalcTop 300 US products by prescriptions, 202427.9% Time explains most of the 19%. GPCR drugs made up 29% of the drugs first approved in the 1970s and in the 1980s, then 19% in the 1990s, 23% in the 2000s, 17% in the 2010s and 12% from 2020 to 2024. Schröer and Seifert counted German approvals from 1987 onwards, one primary target each, so they measured the newer, less GPCR-heavy part of the pharmacopoeia. Hauser and Santos counted every FDA drug ever approved, old antihistamines and beta blockers included. Prescriptions tilt the other way. Weighting the 300 most prescribed US products of 2024 by their prescription counts, 27.9% of 2.66 billion prescriptions were for a product with a GPCR-acting ingredient, from albuterol and losartan to metoprolol, cetirizine and semaglutide. The old GPCR drugs are cheap, generic and taken daily, so they weigh more in a pharmacy than in a list of molecules. None of these figures is the true one; each answers a different question. ## How fast is the number of drug targets growing? Faster than ever. Drugs first approved in the 2010s introduced 137 human targets that no earlier approved drug had reached, more than any previous decade. From 2020 to 2024, the latest years with approval dates in ChEMBL 37, another 91 arrived, about 18 a year. ![Vertical bars of new human drug targets per decade of first approval, rising from 29 before 1950 and 30 in the 1960s to 94 in the 2000s, 137 in the 2010s and 91 from 2020 to 2024](/images/charts/new-human-drug-targets-by-decade.webp '**Figure 3. New human drug targets per decade.** Human efficacy targets in ChEMBL 37 by the first-approval year of their earliest approved drug. 591 of 611 human targets have a dated drug; ChEMBL first-approval years run to 2024, so the last bar covers five years. Source: [ProteinIQ analysis of ChEMBL 37 (2026)](/data/guides/drug-targets/approved-drug-mechanisms.csv.gz).') The new targets come from different families than the old ones. Of the 228 human targets first reached since 2010, 47 are protein kinases and only 27 are GPCRs; before 2010, GPCRs outnumbered kinases 78 to 34. Antibodies added secreted proteins and surface antigens, and oligonucleotides added RNA targets such as transthyretin mRNA. Even so, approved drugs reach only a small part of the genome. Roughly 4,500 human genes are thought to be [druggable](/guides/druggable-genome), against about 600 human targets with an approved drug today. For a protein outside that list, the work starts from structure: predicting a model with [AlphaFold 2](/app/alphafold-2) when no experimental one exists, finding cavities with [fpocket](/app/fpocket), then docking candidate compounds with [AutoDock Vina](/app/autodock-vina). [Inverse virtual screening](/use-cases/inverse-virtual-screening) runs the other way, docking one compound against many targets to suggest which it acts on. ## How we counted drug targets in ChEMBL We queried the ChEMBL REST API on October 29, 2026, which served release ChEMBL_37 of May 1, 2026. An approved drug is a parent molecule with max_phase 4, after folding salts into their parent, and with ChEMBL's therapeutic flag set. That keeps 2,511 of 2,996 approved parents and removes mostly contrast agents, radiotracers and other non-therapeutic products; 150 of the 2,511 are flagged as withdrawn and stay in. ChEMBL curators record each drug's mechanism of action and its target from drug labels and the literature, and flag the interactions thought to produce the clinical effect. We kept those efficacy mechanisms with a named target. Of the 2,421 drugs with a mechanism record, 216 have no assigned target, among them surfactants, many vaccines and drugs whose mechanism ChEMBL lists as unknown. That leaves 2,205 drugs with 2,846 drug-target links, a median of one target per drug. Target classes come from ChEMBL's protein classification of each target's components. GPCRs are every receptor under ChEMBL's G protein-coupled receptor branches; kinases are its protein kinase branch, which includes receptor tyrosine kinases such as HER2 and the insulin receptor. A complex or family gets a class when its classified members agree, otherwise it counts as spanning two classes. Biologics are ChEMBL's antibody, antibody-drug conjugate, protein, enzyme, vaccine, cell and gene therapy types; peptides such as semaglutide sit in the protein type. ChEMBL's classification has quirks that carry into the counts. CD20, the target of rituximab, is classified as an ion channel, and bacterial penicillin-binding proteins, the targets of 55 antibiotics, sit under proteases. First-approval years are missing for 215 drugs, mostly older drugs approved outside the US, so 20 human targets have no date in Figure 3. Prescription shares use ClinCalc's 2024 list, built from the Medical Expenditure Panel Survey, with each product's ingredients matched to ChEMBL by name. The [analysis script](/data/guides/drug-targets/analyze-chembl-drug-targets.py) reruns every number on this page against the current ChEMBL release, using only the Python standard library. The [drug-target links (gzipped CSV)](/data/guides/drug-targets/approved-drug-mechanisms.csv.gz), [target list (CSV)](/data/guides/drug-targets/approved-drug-targets.csv), [class summary (CSV)](/data/guides/drug-targets/target-class-summary.csv), [provenance and filters (JSON)](/data/guides/drug-targets/provenance.json) and [license notes](/data/guides/drug-targets/README.md) hold the results. The script downloads ClinCalc's list itself, and we publish only the prescription shares computed from it. Because ChEMBL is licensed CC BY-SA 3.0, the data files are shared under the same license with credit to ChEMBL and ProteinIQ. We last checked them on October 29, 2026 and plan to refresh them with each ChEMBL release.