Dehydrated skin tends to cause feelings of tightness and easily highlights 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 water in the skin is primarily located 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 is dehydrated, that is, when it lacks water, a condition to differentiate from skin dryness, characterised 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 essential to maintain skin hydration. Several cosmetic actives are recognised 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 for enhancing the water content of the stratum corneum. Indeed, due to its richness in apiogalacturonans, a type of pectin, 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 even 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, which are capable of forming hydrogen bonds with water (H2O).
The moisturising properties of the spirodela 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 formula with 3% 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 moisturising factor (NMF), a set of hygroscopic molecules. For information, about a third of the water contained in the horny layer is bound to NMF molecules.
The hygroscopic nature of Spirodela polyrhiza allows it to have an immediate moisturising effect, while its ability to increase water carriers and sensors gives it a 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 thus 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. As for the immediate hydrating effects of the water lens, they are summarised in the table below.
| Skin area studied | After 3 hours | After 6 hours |
|---|---|---|
| Horny layer | + 17.8% hydration | + 25.1% hydration |
| Epidermis and upper dermis | +11.9% hydration | + 15.8% hydration |
Immediate hydrating effects of the Spirodela.
Source: Supplier document.
The only drawback: no independent clinical studies have been conducted to date to highlight the moisturising properties of duckweed, which limits the strength of the claims associated with this active ingredient, without completely overshadowing them. Further scientific work, carried out by independent research teams, is therefore still needed to better understand the moisturising 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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