Hydroquinone

Summary

Hydroquinone (CHEMBL537) is an approved small-molecule skin lightening agent (ATC D11AX11); indicated across 3 conditions including lentigo.

At a glance

• Status: Approved (max clinical phase 4)
• Modality: Small molecule
• ATC class: D11AX11
• Indications: 3 conditions
• Clinical trials: 12
• Chemistry: 110.11 Da · C6H6O2

Identifiers

Drug identity and classification

Field	Value
ChEMBL ID	CHEMBL537
Name	Hydroquinone
Type	Small molecule
Max phase	4
FDA approved	yes
PubChem CID	785
ChEBI	CHEBI:17594
ATC	D11AX11
Molecular formula	C6H6O2
Molecular weight	110.11
InChIKey	QIGBRXMKCJKVMJ-UHFFFAOYSA-N

SMILES: C1=CC(=CC=C1O)O

IUPAC name: benzene-1,4-diol

ChEBI definition: A benzenediol comprising benzene core carrying two hydroxy substituents para to each other.

Pharmacological roles (ChEBI): cofactor, carcinogenic agent, skin lightening agent, antioxidant.

Other ChEBI roles (chemical / environmental): Escherichia coli metabolite, human xenobiotic metabolite, mouse metabolite.

Also known as: Black and white bleaching cream, CHEBI:17594, CHEMBL537, Eldopaque forte, Eldoquin forte, Hydroquinone, Hydroquinone component of tri-luma, NCI-C55834, NSC-9247, Solaquin forte, hydroquinone, SID11111286

Patent coverage: 121,945 distinct patent families (296,240 SureChEMBL compound mentions), from 1 matched compound structure(s). Mentions count patents naming the compound (not distinct inventions), so promiscuous / reference molecules inflate the mention figure — families are the dedup metric.

Targets

Targets

Broader ChEMBL bioactivity targets: 40 (assay-derived). Sample: Microtubule-associated protein tau, Lysine-specific demethylase 4E, Nuclear receptor ROR-gamma, Prelamin-A/C, ATP-dependent DNA helicase Q1, RecQ-like DNA helicase BLM, 4’-phosphopantetheinyl transferase ffp, 15-hydroxyprostaglandin dehydrogenase [NAD(+)], Thrombopoietin, NPC intracellular cholesterol transporter 1.

Bioactivity

ChEMBL activities: 28 potent at pChembl ≥ 5 of 65 total. Top 30 by potency (10 = 0.1 nM, 6 = 1 µM):

Target	pChembl	Type	Value	Unit	Activity ID
O42275	8.91	Ki	1.22	nM	CHEMBL_ACT_16543709
BLM	8.55	Potency	2.8	nM	CHEMBL_ACT_4745807
BLM	8.55	Potency	2.8	nM	CHEMBL_ACT_4917815
CA2	7.05	Ki	90	nM	CHEMBL_ACT_2172315
CA2	7.05	Ki	90	nM	CHEMBL_ACT_2573074
HSD17B10	6.4	Potency	398.1	nM	CHEMBL_ACT_4829617
CYP3A4	6	Potency	1000	nM	CHEMBL_ACT_5006189
CYP3A4	6	Potency	1000	nM	CHEMBL_ACT_5074696
C7FF04	5.96	IC50	1100	nM	CHEMBL_ACT_22849498
C7FF04	5.96	IC50	1100	nM	CHEMBL_ACT_24365346
HSD17B10	5.9	Potency	1259	nM	CHEMBL_ACT_3710956
HSD17B10	5.9	Potency	1259	nM	CHEMBL_ACT_4845485
HIF1A	5.7	Potency	1995	nM	CHEMBL_ACT_4125693
HIF1A	5.7	Potency	1995	nM	CHEMBL_ACT_4519902
LMNA	5.55	Potency	2818	nM	CHEMBL_ACT_3666983
HPGD	5.25	Potency	5623	nM	CHEMBL_ACT_4767859
MEN1	5.2	Potency	6310	nM	CHEMBL_ACT_3618731
CA12	5.11	Ki	7800	nM	CHEMBL_ACT_2573002
LMNA	5.1	Potency	7943	nM	CHEMBL_ACT_3627353
MAPT	5.1	Potency	7943	nM	CHEMBL_ACT_4515426
HPGD	5.1	Potency	7943	nM	CHEMBL_ACT_4796058
CA3	5.09	Ki	8200	nM	CHEMBL_ACT_2573065
O42713	5.01	IC50	9810	nM	CHEMBL_ACT_2284707
O42713	5	IC50	10020	nM	CHEMBL_ACT_10896333
NFKB1	5	Potency	10000	nM	CHEMBL_ACT_3672754
P0A6C1	5	Potency	10000	nM	CHEMBL_ACT_4084664
NFKB1	5	Potency	10000	nM	CHEMBL_ACT_4586035
HPGD	5	Potency	10000	nM	CHEMBL_ACT_4785232

Target pathways

No target-pathway data for this drug (no mapped target genes).

Indications & clinical

Indications

3 indications (3 at ChEMBL trial phase 4). Phase below is the highest clinical-trial phase recorded for this drug against each disease — not the molecule’s overall approval status (that is in the Summary).

Indication	Trial phase	MONDO	EFO
lentigo	4	MONDO:0021582	MONDO:0021582

2 further indication records had no mapped disease name (EFO/MeSH-only) or were duplicates, and are omitted.

Clinical trials

Total trials: 12.

Phase distribution

Phase	Trials
PHASE4	5
PHASE3	3
PHASE2	3
Not specified	1

Top trials by phase / activity

NCT	Phase	Status	Title
NCT04875715	PHASE4	RECRUITING	Prospective Evaluation of Topical Almond Oil vs Hydroquinone
NCT00927771	PHASE4	UNKNOWN	Azelaic Acid Versus Hydroquinone in Melasma
NCT01661556	PHASE4	UNKNOWN	Clinical Trial of Hydroquinone Versus Miconazol in Melasma
NCT02138539	PHASE4	COMPLETED	Evaluation of an Herbal-Based De-Pigmenting System
NCT07508098	PHASE4	COMPLETED	Comparison of Efficacy of Topical Westerhoff Formula Cream Vs Topical 4% Hydroquinone for the Treatment of Melasma
NCT01001624	PHASE3	COMPLETED	Melanil in the Treatment of Melasma
NCT02095990	PHASE3	COMPLETED	Efficacy and Safety of a 4% Hydroquinone Cream for the Treatment of Melasma
NCT03751163	PHASE3	COMPLETED	Oral Tranexamic Acid and Topical Hydroquinone in the Treatment of Melasma
NCT03982849	PHASE2	COMPLETED	Comparison of Topical Silymarin With Hydroquinone in the Treatment of Melasma
NCT05511948	PHASE2	COMPLETED	Randomized and Open Label Study for Safety and Efficacy of DBI-102 vs. Vehicle vs. Hydroquinone on Skin Pigmentation and Lentigos
NCT06957834	PHASE2	COMPLETED	Efficacy of Eflornithine Hydrochloride Cream in the Treatment of Melasma: A Randomized, Double-blinded, Split-face Controlled Study
NCT04345094	Not specified	COMPLETED	Evaluation of Hexyresorcinol vs Hydroquinone for Photoaging

Clinical evidence (CIViC)

No CIViC predictive evidence (expected for non-precision-medicine drugs).

Pharmacology

Pharmacogenomics

No CPIC/DPWG dosing guideline or drug-level clinical/variant annotations in PharmGKB for this molecule.

Related molecules

Related molecules

No competitor molecules sharing a primary target (ChEMBL phase ≥2 or PubChem drug-class).