OriginEtidronic acid is a synthetic organophosphonate compound belonging to the bisphosphonate chemical family. It is synthesized through phosphonylation reactions, typically involving phosphorous acid reacted with appropriate organic precursors.
Phosphonic acid, (1-hydroxyethylidene)bis-
Solubility 1.15e+01 g/L
Formula
C2H8O7P2
Mol. Weight
206.03
CAS #
2809-21-4
Form
Liquid
State
Liquid; Dry Powder
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Caution
Functions
Chelating
Grabs onto metal ions in water that would destabilize the formula. Keeps your product from going bad or changing color.
Removes Metal Ions
Binds metal ions
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
EWG
4
CIR
Safe as used
Pregnancy
Caution
CIR Safety Findings
Mixed Skin Irritation Results
1 study / 1 mixed / reactions moderate (CIR 729)
Mixed Eye Irritation Results
1 study / 1 mixed / reactions corrosive (CIR 729)
Concentration Guide
Leave-on0.0014–0.12%
Rinse-off0.008–0.9%
0%50%100%
Reg. limit 1.5%
CIR reported use · 2015 survey
EU regulatory limit: 1.5%. (a) 1.5% (as etidronic acid) (b) 0.2% (as etidronic acid) Source: EU Cosmetics Regulation (EC) 1223/2009, Annex III (Restricted Substances), Entry 53.
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