Dehydrated skin tends to cause feelings of tightness and easily shows fine lines. Could it be that the water lens, also known as duckweed, lives up to its name and is capable of restoring skin hydration? Discover more by continuing to read.
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Spirodela, an ally for dehydrated skin?
Summary
Published May 12, 2025,
updated on May 12, 2025,
by
Pauline, Chemical Engineer
—
5 min read
Does Spirodela contribute to more hydrated skin?
Hydration is a key factor for the skin that influences its physical and mechanical properties, particularly at the level of its outer layer, the stratum corneum, also known as the horny layer. Indeed, while the skin's water is primarily found in the dermis, the intermediate layer, its suppleness, softness, and appearance largely depend on the water reserves of the horny layer and rely on mechanisms of diffusion from the dermis and evaporation at the surface of the epidermis. When the skin skin is dehydrated, meaning it lacks water, a condition to differentiate from skin dryness, characterized by a lack of lipids, it is more prone to redness and feelings of tightness.
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Approximately 10%
of water in the stratum corneum.
≈ 70%
of water in the skin.
It is therefore crucial to maintain skin hydration. Several cosmetic actives are recognized for their hydrating properties, such as hyaluronic acid or polyglutamic acid. As for spirodela (INCI: Spirodela Polyrhiza Extract), it is a relatively unknown but promising ingredient to enhance the water content of the stratum corneum. Indeed, due to its richness in apiogalacturonans, a type of pectin, the Spirodela polyrhiza is a highly hygroscopic compound. This means it is capable of attracting and retaining water molecules, a beneficial property for dehydrated skin. An in vitro study has shown that an apiogalacturonan molecule can bind to an average of 23 water molecules. This can be explained by the numerous hydroxyl groups (-OH) present in their chemical structure that are capable of forming hydrogen bonds with water (H2O).
The moisturizing properties of the water lentil do not stop there. This ingredient can activate certain biological levers of hydration. Indeed, a non-independent study showed that the water lentil could increase the expression of certain water carriers, such as aquaporins-3. These are protein channels mainly present in the keratinocytes of the epidermis that conduct water through the skin cells. An emulsion with 0.5% of Spirodela polyrhiza was able to amplify the expression of aquaporins-3 by 41%, while a 3% formula increased the lactate concentration by 51.2%. Lactate is a molecule naturally present in the epidermis. It acts as a water sensor and is part of the natural moisturizing factor (NMF), a set of hygroscopic molecules. For your information, about a third of the water contained in the stratum corneum is bound to NMF molecules.
The hygroscopic nature of Spirodela polyrhiza allows it to have an immediate moisturizing effect, while its ability to increase water carriers and sensors gives it long-term hydrating action.
The non-independent study mentioned earlier not only explored the mechanisms through which the duckweed exerts its hydrating effects, but also evaluated these effects. Two panels of volunteers with dehydrated skin were recruited: 16 individuals applied a 3% emulsion of Spirodela polyrhiza once, while 31 individuals applied this same formulation daily for several weeks. After 42 days, an average increase of 10% in skin hydration was measured. The immediate hydrating effects of the duckweed are summarized in the table below.
| Skin area studied | After 3 hours | After 6 hours |
|---|---|---|
| Stratum corneum | + 17.8% hydration | + 25.1% hydration |
| Epidermis and upper dermis | +11.9% hydration | + 15.8% hydration |
Immediate hydrating effects of the water fern.
Source: Supplier document.
The only drawback: no independent clinical studies have been conducted to date to highlight the moisturizing properties of duckweed, which limits the strength of the claims associated with this ingredient, without completely overshadowing them. Further scientific work, carried out by independent research teams, is therefore still needed to better understand the moisturizing effects of the Spirodela polyrhiza.
Sources
BONTÉ F. & al. Skin hydration: a review on its molecular mechanisms. Journal of cosmetic dermatology (2007).
YANG W. M. & al. Improvement of atopic dermatitis with topical application of Spirodela polyrhiza. Journal of Ethnopharmacology (2016).
CLOSS B. & al. Highlighting the hygroscopic capacities of apiogalacturonans. Journal of Molecular Graphics and Modelling (2023).
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