Ingredient glossary

DMDM Hydantoin

What DMDM Hydantoin does for your skin, who it suits, and what to watch for.

INCI: DMDM Hydantoin · Also: Glydant

Quietly necessary

In short: DMDM Hydantoin delivers preservation, suits most skin types, and the evidence behind it is strong. One thing to know: clear it with your doctor if pregnant; introduce it gently.

What it does
Preservation
Best for
Most skin types
Watch out
Clear it with your doctor if pregnant; introduce it gently
Evidence
Strong
Does it clash with what you use? Check it →

The molecule

Tap to enlarge
Chemical structure of DMDM Hydantoin (DMDM Hydantoin)

The Glow take

Quiet, essential, and nothing to fear.

DMDM Hydantoin keeps a product safe to use from the first pump to the last, at tiny amounts. Not something you pay a premium for.

— Maya

What it does

  • preservation

strong evidenceSafety reviews and patch test data indicate DMDM hydantoin at cosmetic use levels is generally safe for non allergic users but eight to nine percent of the population with formaldehyde allergy may react to products containing it or related releasers.

On a label: usually effective at 0.2-0.6%.

Who it's for, and who should skip it

Tends to suit

  • all

Approach with care

  • formaldehyde allergy
  • very sensitive
  • Clogs poresLow
  • Irritation riskModerate

How it fits each skin type

  • DrySuits
  • CombinationSuits
  • OilySuits
  • SensitiveTake care

Take extra care if any of these apply to you: formaldehyde allergy.

Where it fits in your routine

WhenMorning or evening
Where in the orderAfter cleansing, before your moisturizer

Plays well with

  • other preservatives

DMDM Hydantoin, answered

Is DMDM Hydantoin safe during pregnancy?

Clear it with your doctor first. DMDM Hydantoin is flagged as use-with-caution during pregnancy and breastfeeding, so check with your doctor or midwife before adding it.

Who should avoid DMDM Hydantoin?

Approach DMDM Hydantoin with care if any of these apply to you: formaldehyde allergy and very sensitive. Its irritation risk is moderate, so introduce it slowly and patch test first.

What concentration of DMDM Hydantoin actually works?

DMDM Hydantoin tends to do its job in the 0.2 to 0.6% range. Much lower and it is likely underdosed.

During pregnancy

Treat DMDM Hydantoin as a maybe rather than a yes for now. It is flagged as one to use with caution while pregnant or breastfeeding, so it is worth clearing before you carry on.

When in doubt, check with your doctor or midwife. They outrank any website, including this one.

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Sources & how we reviewed this

Last reviewed July 2026. Educational information about a cosmetic ingredient, not medical advice.