Sodium Polyglutamate Crosspolymer in Skincare: A Superior Hydrator to Hyaluronic Acid with Barrier-Repair Benefits
Hyaluronic acid has long been celebrated as the go-to ingredient for hydration in skincare. But a quieter contender—sodium polyglutamate crosspolymer (a crosslinked form of poly-γ-glutamic acid)—is gaining recognition for its remarkable moisture-retaining properties, barrier-repairing ability, and long-lasting hydration performance. This emerging powerhouse among the best humectants in skincare offers skin-plumping and water-binding benefits that rival hyaluronic acid, making it an ideal choice for those seeking deeply hydrating skincare ingredients that do more than just sit on the surface.
This article offers a clear-eyed look at how sodium polyglutamate crosspolymer compares to hyaluronic acid across five key skincare functions: hydration efficacy, skin barrier support, molecular penetration, formulation stability, and cost. The aim is not to market a miracle molecule, but to provide transparent insights rooted in both science and formulation logic.
1. Hydration That Goes the Distance
Hyaluronic acid can retain up to 1,000 times its weight in water. Sodium polyglutamate crosspolymer, by contrast, binds up to 5,000 times its weight. In lab studies, it has demonstrated superior water-holding capacity and sustained hydration over time.
Where hyaluronic acid offers fast-acting surface hydration and plumping, sodium polyglutamate’s crosslinked structure enables it to form a film on the skin, acting as a water reservoir that slowly releases moisture throughout the day. This makes it particularly effective for dry or moisture-compromised skin.
2. Beyond Moisture: Supporting the Skin Barrier
Hyaluronic acid supports the skin’s barrier primarily through hydration. Well-hydrated skin is less prone to irritation and dryness. However, sodium polyglutamate crosspolymer goes a step further. Research shows it can increase levels of natural moisturizing factor (NMF) components like PCA and lactic acid. It also helps upregulate proteins and enzymes related to skin barrier health, including filaggrin and ceramide synthesis.
In short, while both ingredients hydrate, sodium polyglutamate actively reinforces the skin’s ability to maintain that hydration over time.
3. A Molecular Film That Protects
Due to its crosslinked structure, sodium polyglutamate crosspolymer remains on the skin’s surface, forming a breathable film that helps minimize transepidermal water loss (TEWL). This film-forming property provides an added layer of protection without clogging pores.
Hyaluronic acid’s penetration varies depending on its molecular weight. Low molecular weight (LMW) HA may penetrate slightly into the stratum corneum, offering light hydration beneath the surface, while high molecular weight HA mostly stays at the top layer. Polyglutamate, in contrast, functions best as a surface hydrator—working where moisture loss first occurs.
4. Formulation Performance and Stability
Sodium polyglutamate crosspolymer offers practical benefits in formulation. It acts as a mild thickener, helps stabilize emulsions, and retains its structure even in the presence of salts or varying pH levels. It is also less susceptible to enzymatic degradation compared to HA, which can be broken down by hyaluronidase enzymes naturally present in skin.
This stability makes polyglutamate a reliable choice for long-wear hydration in both serums and moisturizers. While hyaluronic acid remains a highly effective humectant, its stability and longevity on skin may be shorter unless paired with occlusive agents.
5. A Premium Ingredient with Considerations
Sodium polyglutamate crosspolymer is significantly more expensive than hyaluronic acid. Its production involves more complex fermentation and crosslinking steps, and it is often protected under patented technologies. For formulators and brands, this means higher costs—and typically, inclusion in more targeted or premium skincare.
Hyaluronic acid, by contrast, is widely produced and available in multiple grades at a lower cost, making it a mainstay in both luxury and budget-friendly formulations.
That said, sodium polyglutamate’s ability to multitask—hydrating, supporting barrier repair in this peptide- and NMF-rich serum, and improving product stability—means fewer ingredients may be needed to achieve similar or enhanced results.
Final Thoughts
Both hyaluronic acid and sodium polyglutamate crosspolymer have valuable roles in modern skincare. Hyaluronic acid remains a trusted staple, particularly for quick hydration and layering. But for those seeking deeper, longer-lasting moisture with added skin barrier benefits, sodium polyglutamate crosspolymer is worth considering.
It’s not about replacing hyaluronic acid—it’s about expanding the toolkit of effective, skin-compatible ingredients. In that light, polyglutamate isn’t just a trend; it’s a step forward in how we approach hydration and skin health.
Citations & References:
GIGA Fine Chemical Co., Ltd. (Ziga®Moist L80 formulation data)
J Cosmetic Sci., 2023 – “Moisturizing effects of polyglutamic acid vs hyaluronic acid”
Int J Dermatol Res, 2021 – “The Impact of γ-PGA on NMF production and TEWL”
NIH PubMed Central: Comparative Analysis of Humectants (2022)
Cosmetic Formulator’s Handbook: Ingredient Profiles and Functionality (2024 ed.)