Lactobacillus/Reynoutria Sachalinensis Root 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 Lactobacillus/Reynoutria Sachalinensis Root Ferment Filtrate?

Lactobacillus/Reynoutria Sachalinensis Root Ferment Filtrate comes from the roots of Reynoutria sachalinensis, a hardy plant also known as giant knotweed. The roots are cleaned, crushed and then allowed to ferment with the friendly bacterium Lactobacillus. During fermentation the bacteria break down bulky plant molecules into smaller skin-friendly compounds, leaving a watery filtrate rich in amino acids, peptides, organic acids and soothing sugars. After the process is complete the mixture is filtered to remove solids, yielding a clear liquid that blends easily into cosmetic bases.

Fermented botanicals rose to popularity in Korean and Japanese skincare where the quest for gentle yet effective ingredients led formulators to explore traditional fermentation. This particular filtrate is prized for delivering the benefits of knotweed without the need for harsh extraction methods. Today it appears in hydrating sheet masks, lightweight serums, anti aging creams, daily moisturizers and after-sun gels, adding a touch of fermented goodness to both luxury and budget-friendly ranges.

Lactobacillus/Reynoutria Sachalinensis Root Ferment Filtrate’s Cosmetic Benefits/Uses

In formulas this ferment filtrate serves two key roles:

  • Skin conditioning – the mix of amino acids and sugars helps maintain the skin’s moisture balance, leaving it feeling soft, calm and refreshed
  • Emollient – its silky texture fills in tiny surface gaps so skin feels smoother and looks healthier while improving the spreadability of creams and lotions

Who Can Use Lactobacillus/Reynoutria Sachalinensis Root Ferment Filtrate

This ferment filtrate is gentle enough for virtually all skin types. Dry and mature complexions benefit from its moisture-binding sugars while oily or combination skin enjoys its light non-greasy feel. Sensitive skin users usually tolerate it well because the fermentation step removes many harsh plant compounds, though anyone with a known knotweed allergy should proceed with caution.

The ingredient is produced from a plant root and a probiotic bacterium so it is suitable for vegans and vegetarians. As always check the full product label because other ingredients in the formula might not share the same status.

No specific warnings exist for people who are pregnant or breastfeeding. Current data shows no hormonal activity or penetration concerns, yet this is not medical advice and expectant or nursing mothers should run any skincare choices past a qualified healthcare professional first.

The filtrate does not increase photosensitivity, meaning it will not make skin more prone to sunburn. Standard daily sunscreen use is still recommended for overall skin health. The ingredient also plays nicely alongside common actives such as vitamin C, niacinamide and gentle exfoliating acids.

Potential Side Effects/Adverse Reactions

Reactions to topical Lactobacillus/Reynoutria Sachalinensis Root Ferment Filtrate can vary from person to person. The points below outline potential but uncommon side effects. When the ingredient is correctly formulated most users will not experience any problems.

  • Mild redness or transient tingling in very sensitive skin
  • Itchiness or rash in individuals allergic to knotweed or related plants
  • Stinging sensation if applied to broken or freshly exfoliated skin
  • Rare clogging or tiny bumps in those extremely prone to congestion when used in rich occlusive formulas

If any discomfort or unexpected reaction occurs stop using the product and seek advice from a qualified healthcare professional.

Comedogenic Rating

Rating: 0 / 5

The filtrate is a water-light liquid packed with small, hydrating molecules rather than heavy oils or waxes that can block pores. Its primary components are amino acids, peptides and sugars, all of which sit on the skin surface, draw in moisture and rinse away easily. Because it contains virtually no lipids this ingredient earns the lowest possible score on the comedogenic scale.

Suitable for acne-prone or breakout-prone skin since it will not add to pore congestion. Only the surrounding formula matters – rich butters or occlusives paired with it could still trigger bumps in some users.

Summary

Lactobacillus/Reynoutria Sachalinensis Root Ferment Filtrate conditions skin and acts as a mild emollient by delivering moisture-binding amino acids and smoothing sugars that improve texture and comfort. Fermentation breaks down the giant knotweed root into smaller, more bio-available compounds so the skin can soak up benefits without irritation.

You will mostly find this ingredient in Korean and Japanese inspired hydrators, sheet masks and gentle serums rather than mainstream Western lines, although its presence is slowly growing as brands embrace fermented botanicals.

Current data shows it is very safe with a low risk of irritation or acne, making it suitable for nearly every skin type. As with any new skincare step a quick patch test is a smart move to be sure your skin agrees with it.

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