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Ingredient glossary

Propylene Glycol

What Propylene Glycol does for your skin, who it suits, and what to watch for.

INCI: Propylene Glycol · Also: PG, 1,2-propanediol, Propane-1,2-diol

Quietly necessary

In short: Propylene Glycol delivers hydration and solvent, suits most skin types, and the evidence behind it is moderate. One thing to know: introduce it gently.

What it does
Hydration, solvent
Best for
Most skin types
Watch out
Introduce it gently
Evidence
Moderate
How long
Never measured
Does it clash with what you use? Check it →

Written by Maya FaourHow we score →

The molecule

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The Glow take

Quiet, essential, and nothing to fear.

Propylene Glycol 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

  • hydration
  • solvent
  • mildness

moderate evidenceThe backing here is a regulatory safety review, not an efficacy trial: the CIR expert panel concluded propylene glycol is safe in cosmetics when formulated to be non-irritating, and deleted its earlier 50 percent limit rather than lowering it, because the industry use survey behind the review reported it at anywhere from 0.0008 to 99 percent, up to 73 percent in deodorants. Two large patch-test registries found 2.3 percent positive of 45,138 patients and 3.5 percent of 23,359, with already-inflamed skin such as leg dermatitis the one clear risk factor, and a 2023 review notes propylene glycol is negative in predictive sensitisation tests, so how much of that signal is allergy rather than irritation is still unsettled. The panel also noted it can enhance skin penetration of other ingredients by a mechanism it could not identify, and warned it should not be formulated alongside ingredients judged safe only because they do not penetrate.

On a label: usually effective at 1-15%.

Who it's for, and who should skip it

Tends to suit

  • dry
  • normal
  • combo
  • oily
  • dehydrated
  • acne prone

Approach with care

  • very sensitive
  • eczema
  • Irritation riskModerate

How it fits each skin type

  • DrySuits
  • CombinationSuits
  • OilySuits
  • SensitiveTake care

Often chosen for acne prone. Take extra care if any of these apply to you: eczema.

Where it fits in your routine

WhenMorning and evening
Where in the orderOn damp skin, before your moisturizer

Nobody has published how long this takes to work.

What is known, and what is missing

Measured on: stratum corneum hydration (corneometry).

What is known is regulatory and tolerability: a CIR safety review that deleted its old 50% ceiling after an industry survey found use anywhere from 0.0008 to 99%, patch-test positivity of 2.3% and 3.5% in two large registries, and penetration enhancement by a mechanism the panel could not identify. What is missing is any published corneometry or TEWL time course for propylene glycol as a humectant at cosmetic levels, so the base's hydration 6 has no dated measurement behind it. Older dermatology literature uses 40-60% aqueous propylene glycol under occlusion for scaling disorders, which does not describe a 2-5% cosmetic humectant and cannot be borrowed as its timeline.

CIR Expert Panel safety assessment of propylene glycol and the two patch-test registry series cited in the base row; older ichthyosis literature on 40-60% PG under occlusion, described only.

Plays well with

  • humectants
  • preservatives
  • antioxidants

Propylene Glycol, answered

Is Propylene Glycol safe during pregnancy?

Yes. Propylene Glycol is considered safe to use during pregnancy and breastfeeding. As with anything, if you are unsure it is worth a quick word with your doctor or midwife.

Who should avoid Propylene Glycol?

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

What concentration of Propylene Glycol actually works?

Propylene Glycol tends to do its job in the 1 to 15% range. Much lower and it is likely underdosed.

Does it clog pores?

0/5
Non-comedogenic

Published tables rate it 0 of 5 so it is very unlikely to clog.

  • This rating comes from old lab tests on the isolated ingredient, not the finished product.
  • The full formula, how much is used, and your own skin all matter more than one number.
  • If you are acne-prone it is worth noticing, not a reason to avoid it on sight.

Checking a whole product? Paste its list into the pore-clogging checker →

And what "non-comedogenic" on a label actually promises →

Compare Propylene Glycol with

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Sources & how we reviewed this

  1. PMID 23064775abstract only, the full text is paywalled
  2. PMID 36702195abstract only, the full text is paywalled
  3. PMID 29064881abstract only, the full text is paywalled

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