What Is Lactobacillus/Soymilk/Peucedanum Japonicum Leaf/Stem Ferment Filtrate?
Lactobacillus/Soymilk/Peucedanum Japonicum Leaf/Stem Ferment Filtrate is a skin care ingredient born from fermentation technology. It starts with soymilk paired with the leaves and stems of Peucedanum japonicum, a coastal herb long eaten in Japan for its antioxidant rich profile. These plant materials are inoculated with Lactobacillus, a friendly probiotic bacterium. During a controlled fermentation the microorganisms break down larger proteins, sugars and polyphenols into smaller skin compatible molecules. Once the process is complete the mixture is filtered to remove solids, leaving a clear liquid called the ferment filtrate.
The filtrate is naturally rich in amino acids, peptides, lactic acid, vitamins and water binding sugars that originate from both the soybean and the herb. Cosmetic chemists became interested in this blend as Korean and Japanese beauty brands looked for gentle plant based alternatives to synthetic humectants. Its rise in skin care followed the boom of fermented ingredients in the early 2010s, when consumers began associating fermentation with improved absorption and skin comfort.
Today the filtrate is added to hydrating sheet masks, lightweight gel moisturizers, anti aging serums, soothing after sun lotions and even scalp essences. Because it is water soluble it slips easily into the water phase of most emulsions or can be used in clear toners.
Lactobacillus/Soymilk/Peucedanum Japonicum Leaf/Stem Ferment Filtrate’s Cosmetic Benefits/Uses
This ingredient is prized for its ability to draw and hold moisture on the skin’s surface, improving both feel and appearance.
As a humectant it attracts water from the environment and the deeper layers of skin, helping to keep the outer layer plump and flexible. Regular use can soften rough patches, support a dewy finish and enhance the performance of other actives by maintaining an optimal level of hydration. In formulations it can also reduce transepidermal water loss, which is especially helpful in dry or air conditioned settings.
Who Can Use Lactobacillus/Soymilk/Peucedanum Japonicum Leaf/Stem Ferment Filtrate
This ferment filtrate is gentle enough for most skin types including dry, normal, combination, oily and even sensitive since it hydrates without leaving a heavy or greasy film. Acne-prone users often appreciate its lightweight water based texture that will not clog pores. The main group that may need caution are individuals with a known allergy to soy or to plants in the carrot family, as Peucedanum japonicum belongs to that group.
The ingredient is derived from plants and a probiotic culture rather than animal sources so it fits vegan and vegetarian standards. Always check the finished product for any added animal derived additives if cruelty free status is important to you.
No data suggests that topical use poses specific risks to pregnant or breastfeeding women. However this is not medical advice and anyone who is expecting or nursing should run the full ingredient list of any skin care product past their doctor just to be safe.
Lactobacillus/Soymilk/Peucedanum Japonicum Leaf/Stem Ferment Filtrate does not increase the skin’s sensitivity to sunlight so it is not considered photosensitizing. Daily sunscreen is still recommended for overall skin health.
Potential Side Effects/Adverse Reactions
Reactions to skin care ingredients can differ from person to person. The points below outline potential but unlikely side effects when the ferment filtrate is applied topically. When manufactured and preserved correctly most users will not experience any issues.
- Allergic contact dermatitis – rare but possible in those with soy or botanical allergies leading to redness itching or swelling
- Transient stinging or tingling – may occur on freshly exfoliated or very compromised skin barriers
- Minor breakouts – a small subset of acne-prone users might notice clogged pores if the overall formula contains richer emollients alongside the ferment
- Interaction with other actives – extremely low risk yet highly acidic or highly alkaline products used in the same routine could alter the ferment’s pH and reduce its stability
- Product spoilage – if the finished product is poorly preserved the presence of live bacteria residue could encourage microbial growth leading to irritation or infection
If you notice persistent irritation or any unexpected reaction stop using the product and consult a qualified healthcare professional.
Comedogenic Rating
Rating: 0 (non-comedogenic)
This filtrate is almost entirely water with small, water-soluble molecules like amino acids and sugars produced during fermentation. It contains no heavy oils, waxes or fatty alcohols that normally sit in pores and trigger blockages, so it earns the lowest score on the comedogenic scale.
Because of this, it is generally suitable for people who are prone to acne or frequent breakouts.
Keep in mind that the finished product’s overall formula matters; if it pairs this ferment with thick occlusive ingredients the final product could still feel heavy or pore-clogging.
Summary
Lactobacillus/Soymilk/Peucedanum Japonicum Leaf/Stem Ferment Filtrate acts mainly as a humectant, drawing water to the skin and holding it there. Fermentation breaks large plant molecules from soy and Peucedanum japonicum into smaller pieces that can sit comfortably on the skin surface, boosting hydration, softness and a healthy-looking glow.
While not as famous as hyaluronic acid, it has been gaining traction in East Asian beauty circles thanks to the current interest in fermented, plant-based actives. You will most often spot it in lightweight serums, essences and gel creams aimed at dehydrated or sensitive skin.
Topical use is considered very safe with low risk of irritation except for those with soy or carrot-family allergies. As with any new skincare ingredient it is wise to patch test a fresh product first to make sure your skin agrees with it.