A gamechanger for more moisture in your skin

What is polyglutamic acid in cosmetics?

Polyglutamic acid, or PGA for short, is a biotechnologically produced active ingredient in cosmetics that is obtained by fermenting soybeans. It is a high‑molecular‑weight polypeptide made up of many glutamic acid units, water‑soluble and gentle on the skin. In skincare, PGA acts like an invisible bodyguard. It attracts moisture, retains it and supports the skin barrier.

How does polyglutamic acid work on the skin?

Polyglutamic acid (PGA) is a valuable skincare ingredient due to its intense moisturizing effect. Originally used to support wound and burn healing, it is now mainly used for its hydrating properties. On the skin surface, PGA forms a thin protective film that shields against external stressors and reduces transepidermal water loss (TEWL).

As a polymer, PGA has the special ability to bind large amounts of water and hold it in the form of a micro‑gel network within the stratum corneum. This keeps the skin hydrated for a long time, making it appear smoother and plumper with a fresh, rested look.

At the same time, PGA helps to stabilise the skin barrier and increase the skin's resilience to environmental stress. It also improves the uptake of other active ingredients, making care products overall more effective.

Which skin types is polyglutamic acid suitable for?

PGA is particularly suitable for skin that tends to dryness and tightness. It acts as an effective moisturizer and makes the skin noticeably more supple. PGA is generally very well tolerated, which means it is suitable for almost all skin types.

Sensitive skin often reacts to skincare, but PGA is especially well tolerated in this case. The ingredient works gently and generally causes no irritation. In addition, PGA supports skin protection by helping the natural barrier better withstand external stressors.

PGA also offers support for mature skin, where moisture and elasticity decrease over time. It helps preserve these qualities and can reduce visible signs of ageing. Normal to combination skin can likewise benefit from its hydrating properties for a more vital complexion.

How is polyglutamic acid different from hyaluronic acid?

Both polyglutamic acid and hyaluronic acid are among the most effective hydrating substances in cosmetics. They do, however, differ significantly in structure and mode of action.

Hyaluronic acid is a polysaccharide made up of repeating sugar units and occurs naturally in the skin. It has the remarkable ability to bind up to a thousand times its own weight in water. Its effect depends heavily on molecular size. High‑molecular‑weight variants remain on the skin surface and act as a protective shield, while low‑molecular‑weight hyaluronic acids can penetrate deeper. There they bind moisture in the lower layers and can even stimulate the body's own hyaluronic acid production.

Polyglutamic acid is a polymer formed from the amino acid glutamic acid. It has an even greater water‑binding capacity — up to five times more than hyaluronic acid. Due to its larger molecular structure, it generally remains in the upper skin layers, where it forms a moisture‑retaining network known as a micro‑gel. This lays down like a film on the skin, prevents transepidermal water loss and ensures the skin surface appears intensely hydrated, smoother and plumper.

While hyaluronic acid, through its varying molecular weights, can be effective both superficially and at deeper levels, the action of polyglutamic acid is primarily concentrated in the epidermis. Its advantage lies in the exceptional ability to lock in moisture and thus combat dryness effectively. Both ingredients pursue the same goal but differ in depth, mechanism and chemical composition.

Which cosmetic products contain polyglutamic acid?

PGA is now found in a variety of cosmetic products and serves as a versatile moisturiser in modern skincare. It is typically used in serums, which are particularly suitable for dehydrated skin. Building a flexible network on the skin surface prevents water evaporation without weighing the skin down.

In addition, PGA is often found in moisturisers for the face or body, where it also acts as a film former. This traps moisture in the epidermis and strengthens the skin's barrier function. PGA is also present in masks to deliver intensive hydration. The longer contact time with the skin promotes active uptake, which is particularly relevant when the skin needs a stronger moisture boost or barrier support.

Furthermore, PGA is used in eye care products. In this delicate area, PGA‑containing formulations can help soften fine dehydration lines and plump the skin.

The variety of uses is also reflected in common concentrations, which range between 0.3 and 3 percent. This range allows PGA to be used in both light textures and richer formulas, depending on the intended effect.

Are there side effects from using polyglutamic acid?

Because it originates from fermented soy products, PGA is considered particularly well tolerated. As with any new skincare product, however, a patch test before first use is recommended to rule out individual sensitivities.

In very sensitive or reactive skin, irritation can occur in isolated cases, especially when PGA is used together with other active ingredients. Overall, use is considered safe and suitable for longer‑term application. Compared with other cosmetic actives, PGA generally does not irritate the skin and does not cause inflammation or sensitisation.

Polyglutamic acid: how to apply the moisture booster optimally

• Apply polyglutamic acid after thoroughly cleansing the face, before richer products like creams or oils. This way the serum can act as a first layer and immediately deliver moisture to the skin.
• A small amount is often sufficient. A pea‑sized drop of serum or a thin layer of a cream containing polyglutamic acid is enough to supply the skin optimally. This avoids product waste while still achieving maximum effect.
• For an even better result, apply the product to slightly damp skin. This enhances the moisture‑retaining effect, as polyglutamic acid locks in and holds the existing moisture.
• Combine polyglutamic acid with hyaluronic acid for a double hydration boost. While hyaluronic acid draws water into the skin, polyglutamic acid prevents it from being lost again.
• If you use retinol in your routine, polyglutamic acid is an ideal partner. Retinol can dry the skin, while polyglutamic acid balances this effect and protects the skin barrier.
• In the morning, a serum with polyglutamic acid is a good base under your day care or sunscreen. This helps your skin start the day optimally hydrated and resilient.
• Pay attention to the correct concentration. Products should contain at least 0.3% polyglutamic acid to achieve noticeable effects. Higher concentrations are often found in more intensive serums.
• However, do not exceed the recommended limit of 3%. Too high a dosage can weaken the skin barrier and cause irritations such as redness.
• Never apply polyglutamic acid neat. As an acid, it could irritate the skin. Always use finished care formulations that are safely dosed.
• Perform a tolerance test in the crook of the arm before first use to check whether your skin reacts to the active ingredient.
• For serums, dispense a few drops (about three to seven) into the palm and gently press in with the fingertips over face and neck. This distributes the product evenly and improves absorption.

Polyglutamic acid has established itself as a versatile moisture booster in cosmetics, intensely hydrating the skin and strengthening its barrier. When used correctly it can visibly smooth the complexion, prevent dryness and enhance the performance of other actives. Integrate this ingredient consistently into your routine — your skin will thank you with more freshness, firmness and radiance.