Ingredient review
Sodium Polyglutamate
INCI: Sodium Polyglutamate
A next-generation humectant that holds more water than hyaluronic acid and forms a protective film on the skin.
In plain English
Sodium polyglutamate is a water-loving molecule made from fermented soybeans. It can hold thousands of times its weight in water, making it a powerful moisturizer. Unlike some humectants that just sit on the surface, it forms a thin, flexible film that helps lock moisture in and keeps the skin feeling soft and plump. It is often used as an alternative or booster to hyaluronic acid.
Review score
Safety, usefulness, and evidence
Strong fit for many routines
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- biotech
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Easy yes for most routines
Sodium Polyglutamate is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Sodium Polyglutamate.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
Sodium polyglutamate is the sodium salt of polyglutamic acid, a natural polymer produced by fermentation of Bacillus subtilis (a type of beneficial bacteria) using soybeans. It is a long chain of the amino acid glutamic acid.
How it works
It works by attracting and holding water molecules on the skin's surface, creating a reservoir of moisture. Its large molecular structure also allows it to form a breathable film that reduces water loss (transepidermal water loss, or TEWL). This dual action—attracting water and sealing it in—makes it a highly effective hydrator.
Pros
Superior water-holding capacity
Sodium polyglutamate can hold up to 4,000 times its weight in water, which is significantly more than hyaluronic acid. This means it can provide deeper and longer-lasting hydration.
Gentle and non-irritating
It is derived from a natural fermentation process and is generally well-tolerated by all skin types, including sensitive and acne-prone skin. It does not typically cause stinging or redness.
Cons and cautions
Higher cost
Because it is a specialty ingredient produced through fermentation, it is more expensive than common humectants like glycerin. This can make products containing it pricier.
Less research history
While promising, sodium polyglutamate has fewer long-term clinical studies compared to hyaluronic acid. Most evidence comes from short-term studies or ingredient manufacturer data.
Best for
- Anyone with dry or dehydrated skin looking for a potent humectant
- People with sensitive skin who want a gentle, non-irritating moisturizer
Use caution if
- Those with very oily skin may find it too rich if used in high concentrations without balancing ingredients
Usage tips
Safety summary
Sodium polyglutamate is considered very safe for topical use. It has a low irritation and comedogenic risk. Patch testing is always recommended for new products, but adverse reactions are rare.
Research notes
Multiple in vitro and in vivo studies show sodium polyglutamate significantly improves skin hydration and reduces transepidermal water loss. Some studies suggest it also has antioxidant and anti-inflammatory properties. More long-term human trials would strengthen the evidence base.
Common label clues
- Typical concentration
- 0.1% to 1%
- Regulatory status
- Approved for cosmetic use globally, including by the EU CosIng database and the US FDA (as a cosmetic ingredient). No known restrictions.
- Common uses
- Serums, Moisturizers, Sheet masks, Eye creams
- Environmental note
- Produced through bacterial fermentation using renewable plant-based substrates (soybeans). It is biodegradable and considered environmentally friendly.
Good to know
- It is vegan-friendly and produced via fermentation, not animal sources.
- It works well with other humectants like glycerin and hyaluronic acid for a hydration boost.
- The ingredient is stable across a wide pH range, making it versatile in formulations.
Common questions
What is Sodium Polyglutamate in beauty products?
Sodium polyglutamate is a water-loving molecule made from fermented soybeans. It can hold thousands of times its weight in water, making it a powerful moisturizer. Unlike some humectants that just sit on the surface, it forms a thin, flexible film that helps lock moisture in and keeps the skin feeling soft and plump. It is often used as an alternative or booster to hyaluronic acid.
What does Sodium Polyglutamate do in a beauty product?
It works by attracting and holding water molecules on the skin's surface, creating a reservoir of moisture. Its large molecular structure also allows it to form a breathable film that reduces water loss (transepidermal water loss, or TEWL). This dual action—attracting water and sealing it in—makes it a highly effective hydrator.
Is Sodium Polyglutamate safe for most people?
Sodium polyglutamate is considered very safe for topical use. It has a low irritation and comedogenic risk. Patch testing is always recommended for new products, but adverse reactions are rare.
Who should be careful with Sodium Polyglutamate?
Those with very oily skin may find it too rich if used in high concentrations without balancing ingredients
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.