Leuconostoc/Salix Alba Bark Extract 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 Leuconostoc/Salix Alba Bark Extract Ferment Filtrate?

Leuconostoc/Salix Alba Bark Extract Ferment Filtrate is a naturally derived cosmetic ingredient made by fermenting willow bark extract with the friendly microorganism Leuconostoc, a lactic acid bacteria often used in food fermentation. During the process the microbe breaks down the bark’s complex plant material into smaller skin-friendly molecules while also producing mild organic acids and peptides that help preserve the final liquid. The result is a clear watery filtrate rich in salicin-derived compounds from willow bark along with fermentation by-products such as lactic acid and protective peptides. These components give the ingredient gentle exfoliating, soothing and antimicrobial qualities.

Willow bark has centuries of traditional use for calming skin and scalp concerns, while fermentation techniques have long been valued for creating stable bioactive extracts. Combining the two gained popularity in Korean skincare around the early 2010s when formulators looked for natural alternatives to synthetic preservatives. Today the filtrate is produced on an industrial scale: willow bark is steeped in a nutrient solution, inoculated with Leuconostoc, allowed to ferment under controlled temperature, then filtered to remove solids and microbes.

The ingredient shows up in a variety of products including face masks, lightweight moisturizers, anti-aging serums, blemish treatments, scalp tonics and gentle cleansers where brands want a plant-based multitasker that can condition skin or hair while helping keep formulas fresh.

Leuconostoc/Salix Alba Bark Extract Ferment Filtrate’s Cosmetic Benefits/Uses

This fermented willow bark filtrate brings several helpful actions to beauty formulas

  • Anti-Seborrheic: Helps balance excess oil on skin and scalp which can reduce shine and feelings of greasiness
  • Antimicrobial: Keeps unwanted bacteria and yeast in check supporting product freshness and helping minimize breakouts or scalp irritation
  • Hair Conditioning: Smooths the hair cuticle for softer strands and easier detangling while also soothing the scalp
  • Skin Conditioning: Provides light hydration and gentle exfoliation which can leave skin feeling smoother and looking more even

Who Can Use Leuconostoc/Salix Alba Bark Extract Ferment Filtrate

This fermented willow bark filtrate is lightweight and water based so it tends to suit most skin types, including oily, combination, normal and mildly dry skin. Its gentle exfoliating nature helps unclog pores for acne prone complexions while the soothing peptides can calm sensitive or redness prone skin. People with very dry or highly compromised skin may want to pair it with richer moisturizers because mild acids in the filtrate could feel a bit tight on already parched skin. Anyone with a known allergy to aspirin or salicylates should be cautious since willow bark is a natural source of salicin.

The ingredient is made from plant material and a food grade bacterium with no animal derived components so it is considered suitable for both vegans and vegetarians.

No specific warnings are issued for women who are pregnant or breastfeeding when this filtrate is used in standard cosmetic amounts. Salicin levels are low and applied topically, yet every pregnancy is unique. This is not medical advice and expectant or nursing mothers should show any skincare product they plan to use to their doctor just to be safe.

Unlike some exfoliating acids this filtrate is not known to boost photosensitivity. Regular daily sun protection is still wise for overall skin health but you do not need special precautions solely because of this ingredient.

Potential Side Effects/Adverse Reactions

Reactions to topical Leuconostoc/Salix Alba Bark Extract Ferment Filtrate can differ from one person to another. The points below list potential side effects though most users will not run into these problems when the ingredient is properly formulated and used as directed.

  • Mild stinging or tingling on application
  • Temporary redness, especially on very sensitive skin
  • Dryness or light flaking if used too often without adequate moisturizer
  • Allergic response such as hives or swelling in individuals sensitive to willow, aspirin or salicylates
  • Rare contact dermatitis from intolerance to fermentation by products

If any uncomfortable reaction appears stop using the product and seek advice from a healthcare professional if symptoms persist.

Comedogenic Rating

Rating: 1/5. This filtrate is water based and contains no heavy oils or waxes that typically clog pores. Its light acids can actually help keep follicles clear, so the risk of congestion is very low. A rating of 1 reflects the slim chance of it contributing to blackheads or whiteheads while acknowledging that individual sensitivities vary. Overall it is considered suitable for acne prone or breakout prone skin. Because it is also mildly antimicrobial it can further support a clearer complexion.

Summary

Leuconostoc/Salix Alba Bark Extract Ferment Filtrate works as a gentle multitasker: it conditions skin and hair, reins in excess oil, provides mild antimicrobial protection and offers soft exfoliation thanks to organic acids generated during fermentation. Its rise began with Korean beauty formulas that favored natural preservatives, and while it is not as mainstream as hyaluronic acid or niacinamide it is steadily gaining traction among clean beauty and sensitive skin products.

The ingredient has a solid safety profile when used at cosmetic levels with most users experiencing no issues beyond occasional mild tingling or dryness. As with any new skincare product it is wise to do a small patch test first to make sure your skin agrees with it.

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