Polyglutamic Acid (PGA) vs Trehalose: which Korean skincare ingredient?
⏱ 1 min read
⚡ Quick answer: Polyglutamic Acid (PGA) vs Trehalose: Polyglutamic Acid (PGA) leans toward dehydration (water-poor skin), while Trehalose targets dehydration (water-poor skin). Can you use both? Yes — they layer well together.
Polyglutamic Acid (PGA) vs Trehalose: Polyglutamic Acid (PGA) leans toward dehydration (water-poor skin), while Trehalose targets dehydration (water-poor skin). Can you use both? Yes — they layer well together.
| Polyglutamic Acid (PGA) | Trehalose | |
|---|---|---|
| What it is | A fermentation-derived humectant that originates in natto, the Japanese fermented soybean. It is bigger than hyaluronic acid, so it behaves more like a moisture-holding film than a deep hydrator — which is why the two are often stacked. | A disaccharide that some organisms use to survive drying out. That is a good mental model for what it does in a Korean toner — it helps the formula, and your skin, hold onto water. |
| Best for | Dehydration (water-poor skin), Dryness & dehydration, Rough & uneven texture | Dehydration (water-poor skin), Dryness & dehydration, Damaged moisture barrier |
| When to use | BOTH | BOTH |
Which should you choose?
Choose Polyglutamic Acid (PGA) if your priority is Dehydration (water-poor skin); choose Trehalose for Dehydration (water-poor skin). Many Korean routines use both — yes — they layer well together.
Polyglutamic Acid (PGA) guide →Trehalose guide →
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✍️ Written & reviewed by the KoreaPlus Editorial team — dermatologist-informed, cosmetic-science researched & source-cited. Last reviewed: 2026-08-23.
General educational information using cosmetic structure-function wording — not medical advice. Always patch-test new actives. © KoreaPlus.