Sodium Hydroxymethylglycinate

Sodium hydroxymethylglycinate is a synthetic preservative derived from the amino acid glycine. It works by releasing formaldehyde slowly within a product, which inhibits the growth of bacteria, fungi and other microorganisms that could otherwise compromise formula stability and safety.This ingredient is used sparingly in skincare—appearing in roughly 0.1% of products—typically at concentrations well below 1%. It is valued in preservative systems because it releases formaldehyde gradually, which means lower peak concentrations in the finished product compared to some alternative preservatives.

Sodium hydroxymethylglycinate functions as a preservative by releasing small amounts of formaldehyde within the product matrix. This formaldehyde acts as an antimicrobial agent, disrupting microbial cell function and preventing reproduction of bacteria, yeasts and moulds that might otherwise colonise the formula.The slow, controlled release means formaldehyde concentration remains relatively low at any given time, which is considered a safer approach than formulations containing high levels of formaldehyde-donors or free formaldehyde upfront.

This ingredient is a preservative system component, not an active treatment ingredient. It works behind the scenes in formulations; no special application technique is needed. If you use products containing it, apply them as directed by the manufacturer. There is no benefit to seeking it out as a standalone ingredient.

Sodium hydroxymethylglycinate is generally well-tolerated and approved for cosmetic use across major regulatory bodies. People with formaldehyde sensitivity should be cautious, as this ingredient does release small amounts of formaldehyde.