Ingredient intelligence
Hydroquinone
Pigmentation · Hydroquinone (regulated in cosmetics in many regions) · C6H6O2
Hydroquinone is a phenolic analogue. It is restricted or prescription-only in many jurisdictions and is included for mechanistic context.
Any underlined term can be tapped for an everyday-English translation.
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 synthesis.
Gene Ontology GO:0042438
Evidence engine
Moderate
Some human evidence exists, but replication or sample sizes are limited.
Skinceptor Evidence Index
47
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
- Randomised controlled trial1
- Review2
- Total studies
- 3
- Human studies
- 1
- Largest sample
- 60
- Range
- 2006–2013
Index breakdown
- Study design quality60% × 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 share33% × 22%
Proportion of curated evidence measured in people rather than cells or animals.
- Evidence volume63% × 14%
Log-scaled count of curated studies, so volume alone cannot dominate the score.
- Largest sample size59% × 12%
Log-scaled largest reported sample size across curated human studies.
- Replication33% × 12%
Independent human studies, capped at three; one study is never treated as replicated.
- Recency35% × 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)
2011
Hydroquinone safety and regulatory status in topical depigmenting use
Reviewsample size unavailable · American Journal of Clinical Dermatology (review)
2013
Kojic acid combinations for facial melasma: a randomised comparison
Randomised controlled trialn = 60 · Journal of Cosmetic Dermatology
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
3 curated studies
Kojic acid combinations for facial melasma: a randomised comparison
Reported reduced melasma severity scores with a kojic-acid-containing combination versus its comparator over 12 weeks.
Limitations — Combination product prevents attribution to kojic acid alone; identifier not verified during curation.
Hydroquinone safety and regulatory status in topical depigmenting use
Summarises efficacy in melasma alongside reported risks including exogenous ochronosis and the resulting regulatory restrictions.
Limitations — Review; regulatory status varies by region and changes over time; identifier not verified during curation.
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 785Verified 2026-09-14
- UniProt P14679Verified 2026-09-14
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