Ingredient intelligence
Hydroquinone
Pigmentation · Hydroquinone (regulated in cosmetics in many regions) · C6H6O2
Hydroquinone is a phenolic tyrosinase substrate analogue. It is restricted or prescription-only in many jurisdictions and is included for mechanistic context.
Molecular identity
- Formula
- C6H6O2
- Molecular weight
- 110.11 g/mol
- PubChem CID
- 785
- ChEBI
- CHEBI:17594
Biological targets
Tyrosinase (TYR)
high confidenceinhibits · enzyme
UniProt P14679Melanosomal membrane structures
medium confidencemodulates · complex
How could this ingredient interact with biology?
Biological network
Ingredient → molecule → target → gene/protein → pathway → process → studied outcome. Relationship strength is drawn from the curated confidence tier; nothing is added to make the chain look complete.
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1 lower-confidence relationship is hidden at this filter level. Use “Show more biology” to include them.
Text alternative for this network
- Hydroquinone is molecule Hydroquinone — high confidence
- Hydroquinone inhibits Tyrosinase (TYR) — high confidence
- Hydroquinone modulates Melanosomal membrane structures — medium confidence
- Tyrosinase (TYR) encoded by TYR — high confidence
- TYR participates in Melanin biosynthesis — high confidence
- Melanin biosynthesis associated with Melanogenesis — high confidence
- Melanogenesis studied in Regulated substance; strong mechanistic evidence, notable safety restrictions — high confidence
Biological pathways
Melanin biosynthesis
high confidenceCompetitive interference with tyrosinase-catalysed melanin synthesis.
Gene Ontology GO:0042438
Evidence engine
Insufficient
Not enough curated evidence to characterise this ingredient.
Skinceptor Evidence Index
17
experimental · of 100
This index is a research-navigation aid describing how much evidence exists and how it was produced. It is not a medical safety score, an efficacy guarantee, or a clinical recommendation.
Study composition
- Review1
- Total studies
- 1
- Human studies
- 0
- Largest sample
- Data unavailable
- Range
- 2006–2006
Index breakdown
- Study design quality45% × 28%
Mean design weight across curated studies (meta-analysis 1.0, RCT 0.9, other human 0.7, review 0.45, animal 0.35, in-vitro 0.25).
- Human evidence share0% × 22%
Proportion of curated evidence measured in people rather than cells or animals.
- Evidence volume32% × 14%
Log-scaled count of curated studies, so volume alone cannot dominate the score.
- Largest sample size0% × 12%
Log-scaled largest reported sample size across curated human studies.
- Replication0% × 12%
Independent human studies, capped at three; one study is never treated as replicated.
- Recency0% × 7%
Linear decay over a twenty-year window from the most recent curated publication.
- Source traceability0% × 5%
Share of curated studies with a verified PMID or DOI in this dataset.
Insufficient comparable evidence for quantitative synthesis.
Research timeline
How the evidence accumulated
2006
Hydroquinone and the treatment of melasma: efficacy and safety review
Reviewsample size unavailable · American Journal of Clinical Dermatology (review)
Ingredient fingerprint
9 nodes · 9 relationships · seed "hydroquinone"
The fingerprint is a deterministic visual signature: ridge amplitude comes from the number of entities in each tier, node placement from identifier hashes, and opacity from confidence. Two ingredients can never produce the same figure unless their networks are identical.
Open in Biology as Art →Research
1 curated study
Hydroquinone and the treatment of melasma: efficacy and safety review
Summarises hydroquinone as historically the most effective topical depigmenting agent, with dose-related irritation and ochronosis concerns.
Limitations — Review; regulatory status varies widely by jurisdiction.
Community evidence
Submitted by readers
Reader submissions appear here only after review. They are not part of the curated dataset and do not affect the Skinceptor Evidence Index.
No approved community submissions yet.
Sources
- PubChem 785retrieved 2026-09-14
- UniProt P14679retrieved 2026-09-14
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