Kluyveromyces/Lactobacillus/Leuconostoc Soybean Ferment Filtrate: 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 Kluyveromyces/Lactobacillus/Leuconostoc Soybean Ferment Filtrate?

Kluyveromyces/Lactobacillus/Leuconostoc Soybean Ferment Filtrate is a fermented soybean extract that starts with non-GMO Glycine soja beans. The beans are submerged in a nutrient solution and inoculated with three friendly microorganisms: Kluyveromyces yeast plus the probiotic bacteria Lactobacillus and Leuconostoc. Over several days these microbes break down soybean proteins, lipids and sugars into smaller peptides, amino acids, organic acids and antioxidants. The liquid is then filtered to remove the microbes, leaving behind a lightweight, water-soluble filtrate rich in skin-loving compounds.

Fermented ingredients gained attention in Korean skincare during the early 2000s because the fermentation process can boost the bioavailability of nutrients and create new antioxidant molecules. As interest in probiotic skincare spread globally formulators began exploring multi-microbe ferments like this one for their mildness and multitasking benefits.

The filtrate is produced under food-grade, temperature-controlled conditions to ensure consistent pH and microbial safety. After fermentation the liquid is clarified, micro-filtered and preserved, creating a clear to pale-yellow fluid that integrates easily into water phases of cosmetic formulas.

You will often spot this ingredient in leave-on products where its conditioning effect can shine. Common formats include hydrating toners, essence-type lotions, sheet masks, soothing serums, lightweight moisturizers and anti-aging creams. It is also added to rinse-off masks or cleansing milks when brands want a gentle, skin-friendly edge.

Kluyveromyces/Lactobacillus/Leuconostoc Soybean Ferment Filtrate’s Cosmetic Benefits/Uses

This ferment filtrate brings mainly skin conditioning benefits to a formula, helping the complexion feel softer and look healthier. By delivering amino acids and sugars it supports the skin’s natural moisturizing factors, improving water retention and smoothing texture. Antioxidant components from the soybeans can also help shield skin from environmental stress, promoting a fresher appearance.

Who Can Use Kluyveromyces/Lactobacillus/Leuconostoc Soybean Ferment Filtrate

This ferment filtrate is generally suitable for all skin types including dry, normal, combination, oily and sensitive skin because it is lightweight, water based and free of common irritants like alcohol or added fragrance. The only group that may need caution is anyone with a known soy allergy as trace proteins could remain after filtration and trigger a reaction.

The ingredient is produced from non-GMO soybeans using yeast and probiotic bacteria, with no animal-derived substances added at any stage so it meets vegan and vegetarian criteria.

Current research and expert opinion indicate no specific concerns for pregnant or breastfeeding women when using cosmetics containing this ferment. The ingredient is applied topically, its molecules are large and unlikely to penetrate deeply enough to affect the bloodstream. This is not medical advice and anyone who is pregnant or nursing should run all skincare choices past a doctor to be safe.

Kluyveromyces/Lactobacillus/Leuconostoc Soybean Ferment Filtrate does not increase photosensitivity, so it will not make skin more prone to sunburn. Standard daily sunscreen use is still recommended for overall skin health.

Potential Side Effects/Adverse Reactions

Side effects and reactions to the topical application of Kluyveromyces/Lactobacillus/Leuconostoc Soybean Ferment Filtrate can vary from person to person. The following is a list of potential side effects, but most users will not experience them if the ingredient has been formulated and stored correctly.

  • Allergic response in individuals with soy allergy that may appear as itching, hives or swelling
  • Temporary redness or stinging on very sensitive or compromised skin
  • Mild irritation if the product contains additional actives or preservatives that do not agree with the user’s skin
  • Contact dermatitis triggered by an individual hypersensitivity to fermentation by-products

If any negative reaction occurs discontinue use immediately and seek advice from a qualified healthcare professional or dermatologist.

Comedogenic Rating

Rating: 0/5. This ferment filtrate is almost entirely water based and contains no occlusive oils or waxes that could clog pores. Its small molecule amino acids and sugars are readily absorbed or rinsed away, leaving no heavy residue behind. That makes it unlikely to contribute to blackheads or pimples, so it is generally suitable for acne-prone skin. Because the ingredient also has a slightly acidic pH it can even help maintain a healthy skin barrier which indirectly supports clearer pores. Only formulations that combine the filtrate with richer emollients could raise the overall comedogenicity of a finished product.

Summary

Kluyveromyces/Lactobacillus/Leuconostoc Soybean Ferment Filtrate is used in cosmetics as a skin-conditioning agent. During fermentation soy proteins break down into amino acids, peptides and antioxidants that boost hydration and help skin feel smoother while offering light environmental defense. The ingredient is showing up more frequently in K-beauty inspired toners and serums but it is still considered a niche ferment rather than a mainstream staple.

Safety data and user reports point to a low risk of irritation for the average person, with soy allergy being the main caution. As with any new skincare ingredient it is wise to patch test a product before applying it to the entire face just to be safe.

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