Sodium Sulfite vs Formaldehyde (free): which is worse?
Quick answer: Formaldehyde (free) carries the heavier risk profile. Sodium Sulfite is — in the EU and — in the US; Formaldehyde (free) is banned in the EU and allowed in the US.
| Property | Sodium Sulfite | Formaldehyde (free) |
|---|---|---|
| EU status | — | Banned |
| US status | — | Allowed |
| Risk level | — | high |
| Banned in | — | European Union |
| Restricted in | United States (banned from fresh produce and salad bars per FDA 1986 action), European Union (ADI 0.7 mg/kg body weight as sulfur dioxide equivalent), Australia (mandatory labeling if above 10 ppm) | — |
| Category | additive | cmr |
| Where it hides | — | nail hardener, keratin treatment, eyelash glue |
What is Sodium Sulfite?
Sodium sulfite is an inorganic sulfite salt used as a food preservative and antioxidant. It releases sulfur dioxide when it contacts water or acid, which acts as the active antimicrobial and antioxidant agent. Part of the broader sulfite family of food additives (including sulfur dioxide E220, sodium bisulfite E222, and others).
What is Formaldehyde (free)?
Formaldehyde (free) is free formaldehyde used directly as a preservative and in salon hair treatments.
Documented risks
Sodium Sulfite: Sulfites are among the more significant food allergy/intolerance triggers. An estimated 1 in 100 people, and up to 5% of asthmatics, are sulfite-sensitive. Reactions can include urticaria, angioedema, bronchospasm, and in severe cases anaphylaxis. Sulfite-induced asthma can be severe; several deaths attributable to sulfite-triggered anaphylaxis have been documented. The FDA banned sulfites from fresh produce and restaurant salad bars in 1986 after several deaths and severe reactions were linked to sulfite-treated salads. FDA mandates that sulfite content above 10 ppm be declared on US food labels. All forms of sulfites (E220-E228) share these sensitization concerns.
Formaldehyde (free): A known human carcinogen (IARC Group 1). Banned from direct use in EU cosmetics; allowed in US products with limited oversight.
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