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Lactose

Lactose suppliers and sourcing guide

Lactose is the sugar found in milk, a disaccharide of glucose and galactose. Commercial lactose is recovered from cheese or casein whey or whey permeate by concentrating, crystallizing, washing and drying, and pharmaceutical grades are refined further. Brands buy edible grades for foods, infant formula and drink mixes, and pharmaceutical lactose monohydrate or anhydrous lactose as one of the most common fillers for tablets and capsules.

See suppliersWhat to ask for on the COA
Also known as
Milk sugar · Lactose monohydrate · Anhydrous lactose · 4-O-beta-D-galactopyranosyl-D-glucose
Facts checked
November 2026

Forms and grades of lactose

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

  • Edible (food) grade

    Crystalline lactose sold by mesh size for foods, confectionery, bakery and dry mixes.

  • Milled and sieved monohydrate

    Pharmaceutical lactose monohydrate in defined particle size grades, used for wet granulation and capsule filling.

  • Spray-dried lactose

    Spherical, free-flowing particles made by spray drying a lactose slurry, used for direct compression.

  • Anhydrous lactose

    Lactose with little water of crystallization, used where moisture-sensitive actives are tableted.

What to check on the COA

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

Lactose assay
Lactose purity on a dry basis by HPLC, which the US standard of identity requires to be at least 98.0 percent.
Water and loss on drying
Water by Karl Fischer (the monohydrate carries about 5 percent bound water) and loss on drying for free moisture.
Sulfated ash and pH
Sulfated ash and the pH of a 10 percent solution, both limited in the US standard of identity.
Protein and light-absorbing impurities
UV absorbance of a solution, a pharmacopeial check for residual milk protein and other impurities.
Particle size
Laser diffraction or sieve analysis, which sets flow, blend uniformity and tablet hardness.
Microbiology
Total plate count, yeast and mold, coliforms or E. coli, and Salmonella, which matter most when the ingredient goes uncooked into powders, capsules or tablets.

Storage, lots and expiry

Storage and shelf life

Store sealed in a cool, dry place away from odors; anhydrous and spray-dried grades pick up moisture faster than crystalline monohydrate. Lactose can brown with amine-containing ingredients over time, so formulation stability is tested separately. Shelf life or retest date comes from the supplier specification.

Lots and expiry dates

Particle size distribution and water content vary by lot and grade and affect flow, compaction and fill weight. Record both, keep the same grade for a validated product, and label it as a milk-derived ingredient for allergen control.

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.

Lactose suppliers

Manufacturers and distributors whose own websites say they sell it.

We are checking lactose 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 lactose? Request a listing

Frequently asked questions

What forms of lactose can brands buy?

Common forms include edible (food) grade, milled and sieved monohydrate, spray-dried lactose and anhydrous lactose. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for lactose include?

Expect lactose assay, water and loss on drying, sulfated ash and pH, protein and light-absorbing impurities, particle size and microbiology, each with its method, specification and result for that lot.

How should lactose be stored?

Store sealed in a cool, dry place away from odors; anhydrous and spray-dried grades pick up moisture faster than crystalline monohydrate. Lactose can brown with amine-containing ingredients over time, so formulation stability is tested separately. Shelf life or retest date comes from the supplier specification.

What is the regulatory status of lactose?

21 CFR 168.122 defines lactose as the carbohydrate normally obtained from whey, in anhydrous form, as the monohydrate, or as a mixture of both. 21 CFR 168.122 requires a lactose content of not less than 98.0 percent on a dry basis and allows the food to be named "Lactose" or "Milk sugar". Health Canada's Natural Health Products Ingredients Database lists lactose with allowed oral non-medicinal purposes including cryoprotectant and diluent.

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