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Hydroquinone

Hydroquinone suppliers and sourcing guide

Hydroquinone is an aromatic compound, 1,4-benzenediol, made industrially by chemical synthesis, for example by hydroperoxidation of diisopropylbenzene or hydroxylation of phenol. It is a white crystalline solid that darkens as it oxidizes. Most hydroquinone goes into industrial uses such as polymerization inhibitors and photographic developers. In personal care it appears as a pharmaceutical active and in limited hair dye and nail uses.

See suppliersWhat to ask for on the COA
Also known as
1,4-benzenediol · 1,4-dihydroxybenzene · quinol · CAS 123-31-9
Facts checked
November 2026

Forms and grades of hydroquinone

Suppliers sell different products under the same name. Specify the one you need.

  • USP / pharmaceutical grade

    Hydroquinone made to the USP monograph for approved drug products.

  • Technical grade

    Industrial hydroquinone for polymer and chemical uses; not suitable for personal care.

  • Stabilized forms

    Material or premixes with stabilizers such as sodium metabisulfite added to slow oxidation and darkening.

What to check on the COA

Compare each result with your own specification when the lot arrives.

Assay (titration or HPLC)
Hydroquinone content against the USP or supplier specification.
Melting range
Identity and purity check for the crystals.
Related substances
Benzoquinone, catechol and resorcinol by HPLC.
Residue on ignition and heavy metals
Inorganic residue and metals by ICP-MS.
Appearance
Color of the crystals; darkening shows oxidation.

Storage, lots and expiry

Storage and shelf life

Keep hydroquinone in tight, light-resistant containers in a cool, dry place, since air and light oxidize it and turn it brown. Handle it with dust controls and personal protective equipment. Shelf life and retest dates come from the supplier.

Lots and expiry dates

Record assay and color for each lot and do not use material that has darkened. Keep pharmaceutical and technical grades apart and check the regulatory status of the finished product in each market before buying.

Regulatory status

Facts from regulators and standards bodies, each linked to its source.

  • FDA says that since the CARES Act, OTC skin lightening products containing hydroquinone are deemed new drugs and need an approved new drug application before they can be legally marketed.

    Source: fda.gov (opens in a new tab)

  • The same FDA page says many of its safety concerns about hydroquinone in OTC skin lightening drugs also apply to hydroquinone in cosmetic products.

    Source: fda.gov (opens in a new tab)

  • Health Canada's Cosmetic Ingredient Hotlist restricts hydroquinone to 0.3% as an oxidizing colouring agent for hair dyes and 0.1% in nail products, with required warnings.

    Source: canada.ca (opens in a new tab)

  • Health Canada's Natural Health Products Ingredients Database says hydroquinone is on the Prescription Drug List when sold at more than 2% in preparations for topical use on the skin.

    Source: webprod.hc-sc.gc.ca (opens in a new tab)

This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.

Hydroquinone suppliers

Manufacturers and distributors whose own websites say they sell it.

We are checking hydroquinone suppliers now

Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.

Sell hydroquinone? Request a listing

Frequently asked questions

What forms of hydroquinone can brands buy?

Common forms include uSP / pharmaceutical grade, technical grade and stabilized forms. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for hydroquinone include?

Expect assay (titration or HPLC), melting range, related substances, residue on ignition and heavy metals and appearance, each with its method, specification and result for that lot.

How should hydroquinone be stored?

Keep hydroquinone in tight, light-resistant containers in a cool, dry place, since air and light oxidize it and turn it brown. Handle it with dust controls and personal protective equipment. Shelf life and retest dates come from the supplier.

What is the regulatory status of hydroquinone?

FDA says that since the CARES Act, OTC skin lightening products containing hydroquinone are deemed new drugs and need an approved new drug application before they can be legally marketed. The same FDA page says many of its safety concerns about hydroquinone in OTC skin lightening drugs also apply to hydroquinone in cosmetic products. Health Canada's Cosmetic Ingredient Hotlist restricts hydroquinone to 0.3% as an oxidizing colouring agent for hair dyes and 0.1% in nail products, with required warnings. Health Canada's Natural Health Products Ingredients Database says hydroquinone is on the Prescription Drug List when sold at more than 2% in preparations for topical use on the skin.

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