COSMETIC LENS
All ingredients
Active Ingredients

Hydroquinone

对苯二酚

Also known as: HQ

What it does

  • Most potent skin lightener
  • Inhibits melanin production
  • Treats melasma

Effective concentration

Minimum 2% Optimal 4% (Rx)

OTC 2% in many countries. 4% requires prescription. Use max 3-5 months then break.

Evidence

Strong evidence

Gold standard for hyperpigmentation treatment. Must be used under medical supervision.

Skin types

Well suited for: All
Use with caution: Sensitive Darker Skin Tones

Can cause ochronosis with prolonged use. Must use sunscreen.

Helps with

Dark Spots & Hyperpigmentation Melasma Dark Spots

Interactions

Use with care Benzoyl Peroxide

Can temporarily stain skin dark. Avoid using simultaneously.

Works well with Retinol

Retinoids enhance hydroquinone efficacy. Common in Kligman formula.

Irritation potential
Medium
Comedogenic rating
0 / 5
Pregnancy
Avoid during pregnancy

Avoid during pregnancy. Significant systemic absorption.

Good to know

Most effective brightening agent but requires medical guidance. Banned OTC in some countries. Cycle on/off.

References

Compound data from PubChem (U.S. National Library of Medicine).

Further reading

Selected peer-reviewed reviews on this ingredient, indexed by Europe PMC. Provided as background, not proof of any specific claim.

Related ingredients

Tranexamic Acid Kojic Acid Niacinamide Retinol Ascorbic Acid Bakuchiol

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Educational information only — not medical advice. Always patch test and consult a dermatologist for skin concerns.