What Is Bacillus/Monascus/Walnut Shell/Soybean Ferment Filtrate?
Bacillus/Monascus/Walnut Shell/Soybean Ferment Filtrate is a skin care ingredient created by fermenting crushed walnut shells and soybeans with two friendly microbes, Bacillus subtilis and Monascus purpureus. During fermentation the microbes break down the plant material and release a cocktail of helpful molecules, including peptides, amino acids, simple sugars and natural antioxidants such as polyphenols that were locked inside the walnut shell. After the fermentation finishes the mix is filtered to remove solids leaving a clear liquid rich in these skin loving compounds.
Fermented botanicals have been used in East Asian beauty rituals for centuries because the process can boost the potency of the original plants. Modern labs picked up on this idea and started experimenting with different microbe plant pairings. Combining Bacillus and Monascus with walnut shell and soybean turned out to deliver a filtrate that helps protect skin from everyday environmental stress so it found its way into cosmetic formulas in the last decade.
The ingredient is usually produced in stainless steel bioreactors. Walnut shell and soybean meal are cleaned ground and mixed with water then inoculated with the two microbes. Temperature and pH are kept in a sweet spot so the microbes thrive for several days. Once the desired level of active compounds is reached the mixture is pressed and filtered followed by gentle preservation to keep it stable.
Because of its antioxidant punch you will often see this filtrate in serums masks light lotions sunscreens eye creams and products that promise to defend or brighten the skin.
Bacillus/Monascus/Walnut Shell/Soybean Ferment Filtrate’s Cosmetic Benefits/Uses
This ferment filtrate mainly serves as an antioxidant in skin care. By mopping up free radicals it helps slow the look of premature aging caused by sunlight and pollution, supports the stability of other delicate ingredients in a formula and can soothe the appearance of stress related redness giving the complexion a healthier more even tone.
Who Can Use Bacillus/Monascus/Walnut Shell/Soybean Ferment Filtrate
This ferment filtrate is generally friendly to all skin types including dry, oily, combination and sensitive because it is lightweight and water based. People with very reactive or allergy prone skin should check the ingredient list for any additional irritants but the filtrate itself is considered mild.
Because the source materials are walnut shell and soybean, anyone with a known tree nut or soy allergy should avoid products that contain this ingredient or get personalized advice from a healthcare professional first. Trace proteins are usually removed during filtration yet a small risk of cross reaction remains.
The ingredient is produced from plant material using microorganisms so it contains no animal derived substances. That makes it suitable for vegans and vegetarians.
No studies have flagged this ferment filtrate as unsafe during pregnancy or while breastfeeding. It is not absorbed to a significant degree, and it is free of vitamin A derivatives or salicylic acid levels that might raise concern. Still this is not medical advice and pregnant or nursing individuals should run any new skincare product past a doctor to be sure it fits their personal situation.
The filtrate does not make skin more sensitive to sunlight so it is not considered photosensitizing. Daily sunscreen is still recommended for overall skin health.
Potential Side Effects/Adverse Reactions
Responses to topical Bacillus/Monascus/Walnut Shell/Soybean Ferment Filtrate vary from person to person. The following points list potential side effects that are possible but not expected for most users when the ingredient is used correctly in a well formulated product.
- Allergic response – itching, swelling or hives can occur in individuals with walnut or soy allergies if trace proteins remain
- Transient redness or stinging – very sensitive skin may feel a brief tingle when the product is first applied
- Contact dermatitis – rare rash or irritation could arise from residual fermentation byproducts or the product’s overall preservative system
- Breakouts in acne prone skin – unlikely but possible if the finished formula also contains heavy oils or occlusive agents
If any persistent irritation, swelling or other adverse effect develops stop using the product and seek guidance from a dermatologist or healthcare professional.
Comedogenic Rating
Rating: 0–1
This filtrate is water based and contains virtually no oils or waxy residues that could clog pores. The fermentation process breaks down the original walnut shell and soybean material, leaving behind mainly low-molecular-weight peptides, sugars and antioxidants that rinse away easily. Because of this it earns a score at the very bottom of the comedogenic scale.
Acne-prone or breakout-prone users generally tolerate the ingredient well.
As always the finished formula matters more than a single component, so pore-clogging becomes a risk only if the product also includes heavy emollients or occlusive agents.
Summary
Bacillus/Monascus/Walnut Shell/Soybean Ferment Filtrate works chiefly as an antioxidant that scavenges skin-aging free radicals, supports the stability of other actives and helps calm the look of redness. It delivers these perks through a mix of microbe-released peptides, amino acids and polyphenols that are easily absorbed by the skin.
The ingredient is still a bit of an insider pick rather than a mainstream star, showing up most often in niche serums and K-beauty style formulations, yet formulators value it for being plant based, lightweight and versatile.
Current research and consumer feedback point to a high safety profile with only minimal risk for irritation or allergy, mainly in people sensitive to walnut or soy. As with any new skincare addition it is smart to do a patch test first to confirm personal tolerance.