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Sulfur

Sulfur suppliers and sourcing guide

Elemental sulfur for topical products is a yellow, water-insoluble powder. Most is recovered from natural gas and petroleum refining, then purified by sublimation (sublimed sulfur, flowers of sulfur) or by chemical precipitation (precipitated sulfur, a finer powder). Brands buy pharmacopeial-grade precipitated or sublimed sulfur, or colloidal sulfur dispersions, for masks, washes, ointments and shampoos.

Also known as
Sulphur · Precipitated sulfur · Sublimed sulfur · Colloidal sulfur
Facts checked
November 2026

Forms and grades of sulfur

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

  • Precipitated sulfur

    A fine, pale powder made by precipitation, preferred in creams and masks because it disperses more evenly.

  • Sublimed sulfur

    Flowers of sulfur, a coarser crystalline powder made by sublimation; check the monograph grade the product requires.

  • Colloidal sulfur

    Very fine sulfur dispersed with a stabilizer in water or glycerin, sold at a stated sulfur percentage.

  • Pharmacopeial grade

    Material made to a USP or Ph. Eur. monograph, needed when sulfur is the drug active in an OTC product.

What to check on the COA

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

Sulfur assay
Sulfur content on a dried basis by the pharmacopeial method, usually oxidation followed by titration.
Residue on ignition
Ash left after burning, which flags mineral contamination.
Arsenic and heavy metals
Arsenic, lead and other metals by ICP-MS or the compendial method; arsenic is a known impurity of sulfur sources.
Particle size
Sieve or laser diffraction results, which affect grittiness, color and how well the powder suspends.
Loss on drying
Moisture content, kept low so the powder flows and assays correctly.
Acidity
Test for free acid, which can rise if sulfur oxidizes in storage.

Storage, lots and expiry

Storage and shelf life

Store sulfur in closed containers in a cool, dry, well-ventilated area away from heat, sparks and oxidizers, since sulfur dust is combustible. Keep it dry to limit slow oxidation to acidic compounds. Shelf life and retest dates come from the supplier's specification.

Lots and expiry dates

Record the grade (precipitated, sublimed or colloidal), assay and particle size for each lot, because particle size changes texture and color in the finished product. Check acidity on older lots before use.

Regulatory status

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

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.

Sulfur suppliers

Manufacturers and distributors whose own websites say they sell it.

We are checking sulfur 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.

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Frequently asked questions

What forms of sulfur can brands buy?

Common forms include precipitated sulfur, sublimed sulfur, colloidal sulfur and pharmacopeial grade. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for sulfur include?

Expect sulfur assay, residue on ignition, arsenic and heavy metals, particle size, loss on drying and acidity, each with its method, specification and result for that lot.

How should sulfur be stored?

Store sulfur in closed containers in a cool, dry, well-ventilated area away from heat, sparks and oxidizers, since sulfur dust is combustible. Keep it dry to limit slow oxidation to acidic compounds. Shelf life and retest dates come from the supplier's specification.

What is the regulatory status of sulfur?

21 CFR 333.310 lists sulfur at 3 to 10 percent as an OTC monograph active for topical skin products, and at 3 to 8 percent when combined with resorcinol or resorcinol monoacetate. 21 CFR 358.710 lists sulfur at 2 to 5 percent as an OTC monograph active for dandruff products. Health Canada's Anti-Dandruff Products Monograph lists sulfur at 2 to 5 percent as a medicinal ingredient.

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