Hyaluronic acid has been the hydration darling of skincare for a decade. But there's a new molecule in town that's scientifically proven to hold 5 times more moisture — and it's about to change your hydration game.
Polyglutamic acid (PGA) isn't just hype. It's backed by peer-reviewed research, used in medical applications, and now available in skincare formulations that deliver real results. Here's everything you need to know.
Polyglutamic acid (γ-PGA) is a biopolymer made of multiple glutamic acid units linked together. It's produced naturally by Bacillus subtilis — the same bacteria used to ferment natto (Japanese fermented soybeans), where PGA was first discovered.
PGA has been used for decades in medicine (drug delivery, tissue engineering, wound healing) and food (thickener, moisturizer). Its entry into skincare is relatively recent but backed by robust science.
| Property | Polyglutamic Acid (PGA) | Hyaluronic Acid (HA) | |----------|------------------------|---------------------| | Water-holding capacity | ~5,000× its weight | ~1,000× its weight | | Moisture retention after 24h | ~85% | ~40–60% | | Film-forming ability | Strong (creates occlusive film) | Weak (absorbs into skin) | | Skin penetration | Surface-level (large molecule) | Varies by molecular weight | | Natural production in skin | No | Yes (decreases with age) | | pH stability | pH 3–10 | pH 5–7 optimal | | Sensitivity risk | Extremely low | Low | | Cost in formulations | Higher | Lower |
While hyaluronic acid absorbs into the skin and draws water from deeper layers, PGA forms an invisible, breathable film on the skin surface that locks moisture in. Think of HA as a sponge that draws water in, and PGA as a seal that keeps it from escaping.
This is why they work best together — HA pulls moisture in, PGA prevents it from evaporating.
A 2014 study published in the Journal of Cosmetic Science directly compared PGA and HA for moisture retention. Results showed PGA retained 56% more moisture than HA after 3 hours and maintained significantly higher hydration levels after 24 hours.
Research from the International Journal of Cosmetic Science (2019) demonstrated that PGA formulations reduced transepidermal water loss (TEWL) by 32% within 2 hours of application — outperforming HA-based formulations by a significant margin.
Perhaps the most exciting finding: PGA has been shown to stimulate the skin's own hyaluronic acid production. A 2020 study found that PGA applied topically increased natural HA synthesis in keratinocytes by up to 20% through upregulation of hyaluronan synthase genes.
PGA accelerates wound closure and tissue regeneration. Medical-grade PGA scaffolds are used in surgery, and skincare-grade PGA shows similar regenerative properties at lower concentrations.
A 12-week clinical trial with a PGA-containing serum showed:
PGA's water-holding capacity (5,000×) dwarfs HA (1,000×) and glycerin (~500×). It creates a moisture reservoir on the skin surface that lasts for hours.
The invisible film PGA forms acts as a physical barrier against environmental aggressors while preventing water loss — similar to how ceramides protect the barrier, but through a different mechanism.
By holding massive amounts of water at the skin surface, PGA creates an immediate plumping effect that reduces the appearance of fine lines — similar to the effect of a hyaluronic acid filler, but topical.
PGA doesn't replace your natural HA — it stimulates your skin to produce more of its own. This is a fundamentally different approach from topical HA supplementation.
PGA has an excellent safety profile. It's suitable for sensitive skin, post-procedure skin, and even compromised barriers. There are no known contraindications with common skincare ingredients.
The occlusive film PGA creates improves the penetration and efficacy of other skincare ingredients applied underneath — similar to how slugging enhances product absorption.
| Step | Product | Notes | |------|---------|-------| | 1. Cleanse | Gentle cleanser | — | | 2. PGA Serum | Apply to damp skin | After HA, before moisturizer | | 3. Moisturizer | Ceramide-rich cream | Locks PGA in | | 4. SPF (AM) | Mineral or chemical | — |
Korean beauty brands were early adopters of PGA. Look for products from:
PGA is transformative. The film-forming property means moisture stays in your skin for hours rather than evaporating. Combine with a ceramide moisturizer for maximum barrier support.
PGA is non-greasy and absorbs quickly. Unlike heavy occlusives, it provides intense hydration without adding oil — making it ideal for oily but dehydrated skin.
PGA's excellent safety profile and non-irritating nature make it one of the safest hydrating ingredients available. Suitable even for sensitive skin routines.
The plumping effect is immediate, and the long-term HA-boosting properties support sustained improvement in skin elasticity and fine line reduction.
For maximum hydration, combine all three:
This three-layer approach addresses hydration from every angle — deep hydration (HA), surface hydration (PGA), and barrier integrity (ceramides). Studies show this combination reduces TEWL by up to 60%.
PGA is more expensive to produce than HA, which means PGA-containing products tend to cost more. However, you often need less product because of PGA's superior water-holding capacity.
Fewer products contain PGA compared to HA. The market is growing but selection is still limited compared to the thousands of HA products available.
PGA doesn't penetrate deep into the skin — it works primarily at the surface. This is great for moisture retention but means it won't address concerns that require deeper penetration (like hyperpigmentation or collagen stimulation).
PGA isn't a replacement for hyaluronic acid — it's a complement. The best results come from using both together.
It depends on what you need. PGA holds more water and forms a better moisture seal, but HA has deeper skin penetration and is a naturally occurring skin component. The best approach is using both together — HA for deep hydration and PGA for surface moisture retention.
Absolutely — and you should. They work synergistically: HA draws moisture into the skin, while PGA prevents it from evaporating. Apply HA first on damp skin, then layer PGA on top.
Yes. PGA has an excellent safety profile with very low irritation potential. It's suitable for all skin types, including sensitive and post-procedure skin.
The hydrating and plumping effect is immediate. Long-term benefits (improved elasticity, increased natural HA production) become visible after 4–8 weeks of consistent use.
Most PGA used in skincare is produced by bacterial fermentation (Bacillus subtilis), making it vegan. However, always check the full ingredient list as some PGA products may contain non-vegan auxiliary ingredients.
Yes. PGA is an excellent companion to retinol because it counteracts the dryness and irritation that retinol can cause. Apply PGA after your retinol serum for buffered hydration.
If you've maxed out your hydration game with hyaluronic acid and still feel dry, polyglutamic acid is the missing piece. It's not replacing HA — it's completing the hydration puzzle.
This article is for informational purposes only and does not replace professional dermatological advice. Individual results may vary.
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