Hydrated silica
Hydrated silica suppliers and sourcing guide
Hydrated silica is amorphous silicon dioxide that carries bound water, made by reacting sodium silicate solution with acid, then washing, drying and milling the precipitate or gel. It is the main abrasive and thickener in most toothpastes and is also used as an absorbent and texture powder in skin care and makeup. Brands usually buy a named dental abrasive or thickening grade as a white powder.
- Also known as
- Precipitated silica · Silica gel · Silicic acid · Amorphous hydrated silicon dioxide
- Facts checked
- November 2026
Forms and grades of hydrated silica
Suppliers sell different products under the same name. Specify the one you need.
Dental abrasive grades
Precipitated silica with controlled hardness and particle size, offered in low, medium and high cleaning grades rated by radioactive dentin abrasion (RDA).
Dental thickening grades
High-structure silica that builds body in toothpaste and gel dentifrices, usually used alongside an abrasive grade.
Silica gel
Porous gel-type silica used as an absorbent or carrier in skin care and powders.
Food and pharma grades
Material made to food-chemical or pharmacopeial specifications for products sold in several markets.
What to check on the COA
Compare each result with your own specification when the lot arrives.
- Identity and assay
- Identification and silicon dioxide content on an ignited basis, typically gravimetric after hydrofluoric acid treatment.
- Loss on drying and ignition
- Free moisture by loss on drying and bound water by loss on ignition, which define the hydrated grade.
- Particle size and oil absorption
- Median particle size by laser diffraction and oil absorption, which set cleaning, thickening and texture.
- Soluble salts and pH
- Sodium sulfate or soluble salt content and pH of a slurry, which can affect fluoride compatibility in toothpaste.
- Heavy metals
- Lead, arsenic and other metals by ICP-MS or ICP-OES.
- Microbiology
- Total aerobic count, yeast and mold, and absence of specified pathogens.
Storage, lots and expiry
Storage and shelf life
Store hydrated silica sealed in a dry area off the floor, since it absorbs moisture and very fine grades can cake or change flow. Avoid creating dust during charging and keep bags closed between uses. Shelf life and retest dates come from the supplier's specification.
Lots and expiry dates
Record grade, particle size and oil absorption for each lot, because they change paste viscosity and cleaning behavior. When a toothpaste uses a fluoride active, note the silica grade on the batch record, as fluoride availability can depend on the abrasive used.
Regulatory status
Facts from regulators and standards bodies, each linked to its source.
Health Canada's Natural Health Products Ingredients Database lists hydrated silica as a source ingredient for silicon dioxide (CAS 7631-86-9).
Source: webprod.hc-sc.gc.ca (opens in a new tab)The same database entry lists abrasive, absorbent and thickening agent among silicon dioxide's non-medicinal purposes.
Source: webprod.hc-sc.gc.ca (opens in a new tab)Health Canada's Oral Health Products monograph sets, for stannous fluoride dentifrices, a separate available fluoride ion minimum of 600 mg/kg for products containing the abrasive silica.
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.
Hydrated silica suppliers
Manufacturers and distributors whose own websites say they sell it.
We are checking hydrated silica 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 hydrated silica? Request a listingFrequently asked questions
What forms of hydrated silica can brands buy?
Common forms include dental abrasive grades, dental thickening grades, silica gel and food and pharma grades. Ask each supplier for the specification sheet of the exact grade they quote.
What should the COA for hydrated silica include?
Expect identity and assay, loss on drying and ignition, particle size and oil absorption, soluble salts and pH, heavy metals and microbiology, each with its method, specification and result for that lot.
How should hydrated silica be stored?
Store hydrated silica sealed in a dry area off the floor, since it absorbs moisture and very fine grades can cake or change flow. Avoid creating dust during charging and keep bags closed between uses. Shelf life and retest dates come from the supplier's specification.
What is the regulatory status of hydrated silica?
Health Canada's Natural Health Products Ingredients Database lists hydrated silica as a source ingredient for silicon dioxide (CAS 7631-86-9). The same database entry lists abrasive, absorbent and thickening agent among silicon dioxide's non-medicinal purposes. Health Canada's Oral Health Products monograph sets, for stannous fluoride dentifrices, a separate available fluoride ion minimum of 600 mg/kg for products containing the abrasive silica.
More cosmetic bases, emollients and surfactants
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- Butylene glycol1,3-Butanediol · 1,3-Butylene glycol
- Propanediol1,3-Propanediol · Trimethylene glycol
- Pentylene glycol1,2-Pentanediol · Pentane-1,2-diol
- Cetearyl alcoholCetostearyl alcohol · Alcohols, C16-18
- Cetyl alcohol1-Hexadecanol · Palmityl alcohol
- Stearyl alcohol1-Octadecanol · Octadecyl alcohol
- Behenyl alcoholDocosanol · 1-Docosanol
- Caprylic/capric triglycerideMedium-chain triglycerides · MCT
- Isopropyl myristateIPM · Tetradecanoic acid, 1-methylethyl ester
- Isopropyl palmitateIPP · 1-Methylethyl hexadecanoate
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