Parachlorella Kessleri Exopolysaccharides: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: July 1, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Parachlorella Kessleri Exopolysaccharides?

Parachlorella Kessleri Exopolysaccharides are long-chain sugars secreted by the microalgae Parachlorella kessleri during fermentation. These water-loving molecules are rich in repeating units of glucose and other simple sugars that bind readily to moisture. Although microalgae have been collected for centuries as food or fertilizer, interest in their exopolysaccharides for skin care is fairly recent. Researchers looking for natural hydrators discovered that the gel-like layer released by Parachlorella acts much like hyaluronic acid, sparking its first cosmetic use in early 2010s niche moisturizers. Today manufacturers cultivate the algae in closed tanks, feed it a controlled nutrient mix then gently trigger fermentation. The liquid culture is filtered to separate the polysaccharide-rich broth, which is purified, concentrated and finally dried into a stable powder for formulators.

You will come across Parachlorella Kessleri Exopolysaccharides in hydrating serums, sheet masks, soothing after-sun gels, creamy moisturizers and anti-aging treatments that promise a plumper appearance. Because it dissolves easily in water and leaves a weightless finish, it also shows up in refreshing facial mists and lightweight lotions aimed at oily or combination skin.

Parachlorella Kessleri Exopolysaccharides’s Cosmetic Benefits/Uses

This ingredient is prized for the way it boosts a formula’s ability to attract and hold water while comforting the skin surface.

  • Humectant: Draws moisture from the environment and deeper skin layers to the outermost surface, helping skin feel instantly softer, smoother and more supple. This can visibly reduce the look of fine lines caused by dehydration and supports a healthy skin barrier.
  • Skin Conditioning: Forms a thin, breathable film that leaves skin feeling silky rather than sticky, improves texture over time and supports other actives by keeping the micro-environment optimally hydrated.

Who Can Use Parachlorella Kessleri Exopolysaccharides

Because it is a lightweight yet highly hydrating humectant, Parachlorella Kessleri Exopolysaccharides suits nearly all skin types including dry, sensitive, mature, oily and combination. Its film-forming action is breathable and non-greasy so it rarely weighs down oily skin or worsens breakouts. There are no known reasons for very dry or reactive skin to avoid it unless an individual has a specific algae sensitivity.

The ingredient comes from a microalgae grown in closed tanks with a plant-based nutrient feed so it contains no animal derivatives making it suitable for vegans and vegetarians.

Current safety data indicates it poses a very low risk to people who are pregnant or breastfeeding. Still this is not medical advice and anyone expecting or nursing should check with a qualified healthcare provider before adding new skincare to their routine.

Parachlorella Kessleri Exopolysaccharides does not make skin more sensitive to sunlight so it can be used morning and night without raising the need for extra sun protection beyond the usual daily SPF.

Potential Side Effects/Adverse Reactions

Responses to any cosmetic ingredient differ from person to person. The effects listed below are uncommon and most users will not experience them when the product is well formulated and used as directed.

  • Mild redness or stinging particularly on very reactive or damaged skin
  • Local itching or burning if an allergy to algae derivatives is present
  • Contact dermatitis in rare cases where the preservative system or trace fermentation by-products trigger sensitivity
  • Acne-like breakouts extremely rare and usually linked to other richer ingredients in the same formula rather than the polysaccharide itself

If irritation or any other negative reaction occurs stop using the product and consult a dermatologist or healthcare professional for guidance

Comedogenic Rating

Rating: 0/5

Parachlorella Kessleri Exopolysaccharides are large water soluble sugar molecules that stay on the skin surface rather than sinking into pores. They contain no oils or fatty acids and form a lightweight breathable film similar to hyaluronic acid, which means they have virtually no pore-clogging potential.

This makes the ingredient suitable for people who are prone to acne or frequent breakouts.

As always the final product’s overall formula plays a role, so rich oils or heavy occlusives paired with it could still trigger congestion even if the polysaccharide itself does not.

Summary

Parachlorella Kessleri Exopolysaccharides act mainly as a humectant and skin conditioning agent. They latch onto water in the air and in deeper skin layers then hold it at the surface, creating an invisible moisture net that leaves skin feeling plump smooth and comfortable. The thin film they form also softens texture and helps other actives work in a well hydrated environment.

While effective, the ingredient remains more of a niche hydrator than a household name like glycerin or hyaluronic acid, showing up mostly in specialty serums masks and lightweight gels.

Current research and real-world use point to a very safe profile with a low risk of irritation or clogged pores. Still it is smart to patch test any new product to make sure it plays nicely with your unique skin.

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