Polyglutamic Acid (PGA) vs Birch Sap: which Korean skincare ingredient?
⏱ 1 min read
⚡ Quick answer: Polyglutamic Acid (PGA) vs Birch Sap: Polyglutamic Acid (PGA) leans toward dehydration (water-poor skin), while Birch Sap targets dehydration (water-poor skin). Can you use both? Yes — they layer well together.
Polyglutamic Acid (PGA) vs Birch Sap: Polyglutamic Acid (PGA) leans toward dehydration (water-poor skin), while Birch Sap targets dehydration (water-poor skin). Can you use both? Yes — they layer well together.
| Polyglutamic Acid (PGA) | Birch Sap | |
|---|---|---|
| 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. | Round Lab built a hero line on it. Substituting a botanical sap for plain water is partly formulation, partly storytelling — the appeal is the light, clean feel rather than any single dramatic active. |
| Best for | Dehydration (water-poor skin), Dryness & dehydration, Rough & uneven texture | Dehydration (water-poor skin), Reactive & easily-stung skin, Dryness & dehydration |
| When to use | BOTH | BOTH |
Which should you choose?
Choose Polyglutamic Acid (PGA) if your priority is Dehydration (water-poor skin); choose Birch Sap for Dehydration (water-poor skin). Many Korean routines use both — yes — they layer well together.
Polyglutamic Acid (PGA) guide →Birch Sap guide →
Related K-beauty guides
Try the free tools
🪞 Find your skin type🧴 Build a routine🧪 Decode any INCI list⚗️ What not to mix🔮 Glass Skin Score🩺 Troubleshoot skin🛡️ Where to buy authentic
Explore more K-beauty guides →
⏭ Up next⚖️ Polyglutamic Acid (PGA) vs Bamboo Sap: which Korean skincare ingredient?
✍️ 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.