What does Boron oxide (B2O3) do?

Used in consumer products as a stabiliser.

Is Boron oxide (B2O3) safe?

Critical concern: classified for carcinogenic, mutagenic or reproductive toxicity (CMR). It is banned in EU cosmetics.

beauty
cleaning
industrial
pharma

Boron oxide (B2O3)

CAS 1303-86-2 · 100/100 · High conf.

Also registered as 14 other CAS numbers

12640-42-5 · 54566-73-3 · 56116-04-2 · 56145-44-9 · 56312-91-5 · 56312-92-6 · 56312-93-7 · 56312-94-8 · 91863-27-3 · 102967-73-7 · 144919-64-2 · 163701-88-0 · 1858211-82-1 · 2566446-91-9

Concern score

100/100Critical concern driven by cmr.

High confidence

Boron oxide (B2O3) in plain language

What it is: Also known as Boron oxide · Diboron trioxide; boric oxide · Boric anhydride · Boric oxide · Boron sesquioxide · Boron trioxide
Show all 22 names
Boron oxide (2/3) · Diboron trioxide · B2O3 · Boracic anhydride · Boria · Boric acid (HBO2), anhydride · Boric acid anhydride · Boric oxide (B2O3) · Boron Oxydatum · Caswell No. 109B · Diboron Trixoxide · Fused boric acid · boric acids (boron oxide) · boron oxide (bo) · boron oxide. % (wt):0.0005-0.005 · boron oxide/boric anhydride
What it does: Used in consumer products as a stabiliser.
Stabiliser
Is it a concern?: Critical concern: classified for carcinogenic, mutagenic or reproductive toxicity (CMR). It is banned in EU cosmetics.

Why it's flagged

Diboron trioxide; boric oxide is prohibited in cosmetic products under Annex II of the EU Cosmetics Regulation (EC) 1223/2009.

RestrictedEU EC — banned

The score describes this ingredient's chemical identity — its hazard profile from published classifications and regulatory status — not the safety of any product it appears in.

Regulation

Restrictions first, then routine listings from published regulatory sources.

In marketed US drugs
EU Annex II — prohibited
EU prohibited in cosmetics

Recorded in these product areas

Found in consumer products
Cleaning
Industrial

EUEC
Annex II of EU Cosmetics Regulation (EC) 1223/2009: substances prohibited in cosmetic products. CMR: Reprotoxic Cat. 1B()
banned
View source →

EUCosIngActiveCosmetics Regulation annex II / ref 1394.
- Cosmetics Regulation annex II / ref 1394.Source →
USEPAcommercial use observedEPA CPDat observed this chemical in 726 composition records across product categories including Furniture and furnishings, Specialty occupational products, Laboratory supplies. EPA CPDat classifies this chemical for functional uses including glaze, Chemical reaction regulator, Stabilizing agent.
- EPA CPDat observed this chemical in 726 composition records across product categories including Furniture and furnishings, Specialty occupational products, Laboratory supplies. EPA CPDat classifies this chemical for functional uses including glaze, Chemical reaction regulator, Stabilizing agent.Source →
USFDAmarketed drug occurrenceFDA NDC lists this ingredient in 9 active drug products and 9 total products.
- FDA NDC lists this ingredient in 9 active drug products and 9 total products.Source →
USFDAlisted in openFDA substanceopenFDA substance registry classifies this ingredient as chemical.
- openFDA substance registry classifies this ingredient as chemical.Source →

Expert safety opinions

No expert opinion on file for Boron oxide (B2O3). These are the independent scientific bodies that assess ingredients like this one; we show an opinion only when a record we hold cites it.

SCCS
EU Scientific Committee on Consumer Safety
No SCCS opinion on file.
CIR
Cosmetic Ingredient Review (US expert panel)
No CIR safety assessment on file.

Evidence & sources

No graded research studies for Boron oxide (B2O3) yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.

8 data sources

Where this comes from

CosIng
regulatory · updated 2026-09-23
Open →
EU CosIng Cosmetics Regulation Annexes
regulatory · updated 2020-07-30
Open →
EPA Chemical and Products Database
exposure · updated march 23, 2017
Open →
EPA DSSTox Identifiers
chemistry · updated 2025-12-29
Open →
FDA National Drug Code Directory
regulatory · updated 2027-12-31
Open →
FDA GSRS UNII
registry · updated 2026-02-26
Open →
openFDA Substance
registry · updated 2026-05-24
Open →
PubChem Live Enrichment
chemistry · updated 2026-05-17
Open →

Suitability

Context-specific fit derived from published classifications and the current ingredient evidence profile.

Fragrance avoidance

No fragrance-linked caution surfaced in the current profile.

Good fit

This ingredient does not currently read as a fragrance-linked driver in the published evidence and hazard profile.

Where it has been recorded

How often EPA CPDat has listed Boron oxide (B2O3) in a product composition. These are source records, not Greenveil catalog products.

Source records

726

Named organisations

Furniture and furnishingsSpecialty occupational productsLaboratory suppliesBatteriesRaw materialsIndustrial products

Typical roles

Stabiliser

See products using Boron oxide (B2O3) →