The quick version: Rice water for skin has a little real evidence behind it: a small 2002 study found that bathing in rice-starch water helped irritated skin recover its barrier faster. Fermented ingredients such as galactomyces and bifida ferments have a few small human studies, some funded by manufacturers, plus a lot of lab data. Both are gentle, pleasant additions to a routine, not replacements for sunscreen, moisturizer or proven actives.
Rice and fermentation run deep in Korean food culture. Kimjang, the communal autumn making and sharing of kimchi, was added to UNESCO’s list of the intangible cultural heritage of humanity in 2013 (UNESCO). It’s no surprise that rice extracts, rice ferments and other fermented ingredients became signatures of Korean skincare. Here’s how to separate the heritage and the marketing from what the research supports.
What’s inside
What the research says about rice water for skin
Rice water is the cloudy, starchy liquid left after rinsing or soaking rice. The most relevant study tested rice starch as a bath additive. Researchers irritated volunteers’ forearm skin with a harsh detergent (sodium lauryl sulfate), then had them soak in rice-starch water twice a day for 15 minutes. Damaged skin recovered its barrier about 20% better, measured by water loss. People with atopic dermatitis also showed improved barrier function when starch was added to their bath water (De Paepe et al., 2002).
That’s encouraging, with limits. It was a small study, it tested starch baths rather than facial toners, and it measured barrier recovery rather than tone or glow. Claims that rice water “brightens” or “tightens” skin come mainly from lab studies of rice compounds, not from trials of rice water on faces.
Why skincare uses fermented ingredients
Fermentation uses yeasts or bacteria to transform a starting material. A 2022 review in Molecules explains the cosmetic rationale: fermentation breaks large molecules into smaller ones and can add new compounds made by the microorganisms, such as amino acids and other metabolites, which may make an extract more active. The same review is candid about the evidence, which is mostly lab-based with limited clinical testing, and notes that practical use of these ingredients in finished cosmetics has been modest (Majchrzak et al., 2022).
On ingredient lists, fermented ingredients usually include the word “ferment”: for example galactomyces ferment filtrate, bifida ferment lysate, lactobacillus ferment, or a fermented plant extract. A “ferment filtrate” is the liquid left after the microorganisms are filtered out; a “lysate” contains broken-down microbial cells. None of them are live probiotics.
Worth remembering
- Rice-starch baths helped damaged skin recover its barrier in a small 2002 study.
- Fermentation can make plant extracts more active in the lab; human data are limited.
- The best-studied ferments (bifida, galactomyces) rest on a handful of small trials.
- Fermented skincare contains no live bacteria and is not a probiotic.
Fermented ingredients and their evidence
| Ingredient | Best human evidence we found | Caveats |
|---|---|---|
| Rice starch (rice water) | Faster barrier recovery after irritation; better barrier in atopic skin (bath use) | Small study; not facial products |
| Bifida ferment lysate | Less skin sensitivity and dryness over 2 months in 66 women with reactive skin | 10% extract in a cream; single trial |
| Galactomyces ferment filtrate | Reduced pore area, roughness and redness over 4 weeks in two small studies | No placebo group; manufacturer-funded |
| Fermented ginseng | Anti-wrinkle effect in 23 people over 8 weeks (cited in a 2022 review) | Very small |
| Other plant ferments | Mostly lab studies | Effects in people largely untested |
Bifida ferment lysate
In a randomized, double-blind, placebo-controlled trial, 66 women with reactive skin applied either a cream with 10% Bifidobacterium longum lysate or a control cream twice a day for two months. The lysate group became significantly less sensitive to a standard stinging test, their barrier held up better to repeated tape-stripping, and dryness scores fell by day 29 (Guéniche et al., 2010). It’s one of the better-designed studies in this category, but it’s a single trial, so treat it as promising rather than settled.
Galactomyces ferment filtrate
Galactomyces ferment filtrate is a yeast-derived ferment used in many essences. Two eight-week studies of young Japanese women (47 and 57 participants) tracked facial skin three times a day, then had participants use a galactomyces-based formula for four weeks. Pore area, roughness and redness decreased in both studies. There was no placebo group, and several authors worked for or received funding from the manufacturer (Miyamoto et al., 2021).
Homemade rice water: what to know
Making rice water at home is common advice on social media. If you try it, keep it simple and sanitary:
- Make it fresh. Homemade rice water has no preservative. Use it the same day and throw away what’s left.
- Don’t “ferment” it on the counter. Leaving rice water out to sour is not the same as the controlled fermentation used to make cosmetic ingredients, and you can’t know what grew in it.
- Use it as a rinse, not a leave-on. Splash, then follow with your usual moisturizer.
- Patch-test first. The American Academy of Dermatology suggests testing anything new on a small area of the inner arm twice a day for seven to 10 days (AAD).
A commercial rice toner or rice-extract essence is the more predictable option: it’s preserved, consistent and tested for stability.
How to use rice and ferment products in a routine
Rice and fermented ingredients usually come as toners, essences and serums, so they slot in after cleansing and before moisturizer. A ferment essence can replace a hydrating toner rather than adding another layer. If your skin is sensitive, choose fragrance-free formulas and introduce one new product at a time. For step order, see our guide to Korean skincare routine order; for the full picture, the Korean skincare routine pillar.
Reading the label helps you know what you’re getting. A product called “rice” might list a rice extract near the end or a rice ferment near the top. Our guide on how to read a Korean skincare label explains how. If you want a barrier-focused product with stronger evidence, look at ceramides or niacinamide.
Check with a dermatologist if
- A homemade or fermented product causes redness, itching, bumps or swelling.
- You have eczema that flares despite gentle care; ask before relying on bath additives.
- Breakouts appear or worsen after adding a ferment essence.
Frequently asked questions
Is rice water good for your face?
It’s generally gentle. The best evidence is a small study showing rice-starch baths helped irritated skin recover. There’s no strong evidence it brightens or tightens facial skin.
Can I leave rice water on my face overnight?
It’s better used as a rinse. Homemade rice water isn’t preserved, and a commercial rice toner or essence is a more reliable leave-on option.
Are fermented skincare products probiotics?
No. Ferment filtrates and lysates contain no live microorganisms. They’re ingredients made by or from microbes, so “probiotic skincare” is a marketing term.
Are fermented ingredients good for sensitive skin?
Some may be. A bifida ferment lysate cream reduced sensitivity in a controlled trial of women with reactive skin. Patch-test any new product, since the whole formula matters.
Sources
- UNESCO. “Kimjang, making and sharing kimchi in the Republic of Korea.” Intangible Cultural Heritage, 2013. ich.unesco.org
- De Paepe K, Hachem JP, Vanpee E, Roseeuw D, Rogiers V. “Effect of rice starch as a bath additive on the barrier function of healthy but SLS-damaged skin and skin of atopic patients.” Acta Dermato-Venereologica, 2002. pubmed.ncbi.nlm.nih.gov
- Majchrzak W, Motyl I, Śmigielski K. “Biological and Cosmetical Importance of Fermented Raw Materials: An Overview.” Molecules, 2022. pmc.ncbi.nlm.nih.gov
- Guéniche A, Bastien P, Ovigne JM, et al. “Bifidobacterium longum lysate, a new ingredient for reactive skin.” Experimental Dermatology, 2010. pubmed.ncbi.nlm.nih.gov
- Miyamoto K, Dissanayake B, Omotezako T, et al. “Daily Fluctuation of Facial Pore Area, Roughness and Redness among Young Japanese Women; Beneficial Effects of Galactomyces Ferment Filtrate Containing Antioxidative Skin Care Formula.” Journal of Clinical Medicine, 2021. pubmed.ncbi.nlm.nih.gov
- American Academy of Dermatology. “How to test skin care products.” AAD. aad.org
This guide is general information, not medical advice. If a product irritates your skin, stop using it and check with a dermatologist.