What is rice water for hair? Benefits, evidence, and how to use it

Rice water for hair has gone from an ancient East Asian beauty tradition to one of the most searched natural hair care topics in the world. If you've seen the viral before-and-after videos or read about the women of Yao in China whose hair reportedly grows to floor length, you've likely wondered whether there's real substance behind the trend — or whether it's just social media noise.

The answer is that rice water has genuine documented benefits for hair, and the fermented version has additional properties that make it more effective than plain rice water. This guide covers the science, the honest limitations, and how to use it correctly.

Quick summary

What it is: The starchy liquid produced by soaking or boiling rice — rich in inositol, amino acids, vitamins B and E, and minerals
Key benefit: Inositol, a carbohydrate compound in rice water, can penetrate the hair shaft and reduce friction and breakage — uniquely, it remains in the hair even after rinsing
Fermented vs plain: Fermentation lowers the pH of rice water closer to the natural pH of hair and increases the concentration of beneficial compounds, making it more effective for strengthening and nourishing
Best for: Dry, damaged, or breakage-prone hair — anyone wanting to improve shine, manageability, and strand strength
Not a standalone growth treatment: Rice water strengthens existing hair and reduces breakage; it is not a clinically proven follicle stimulant in the same way as rosemary oil
Where to find it: Selfwise Rosemary & Rice Water Hair Growth Spray

What is rice water?

Rice water is the liquid that remains after rice has been soaked in water or boiled. It contains a range of compounds that transfer from the rice grain into the water during soaking — including starch, inositol, vitamins B1, B3, and B6, vitamin E, minerals including magnesium and zinc, and amino acids.

Its use in hair care dates back centuries in East and Southeast Asia. The most frequently cited example is the women of the Red Yao ethnic minority in Huangluo village in Guangxi, China, who are documented to maintain extraordinarily long hair — often exceeding 1.5 metres — and attribute their hair health to fermented rice water rinses. This tradition attracted the attention of Japanese cosmetics companies in the early 2000s, leading to some of the first formal research into rice water's effects on hair.

What does rice water actually do to hair?

The most important compound in rice water for hair is inositol — a carbohydrate that belongs to the vitamin B family. Research published in the International Journal of Cosmetic Science identified inositol as the primary active compound responsible for rice water's hair benefits.

Inositol has two documented properties that are directly relevant to hair health:

It penetrates damaged hair. Inositol molecules are small enough to enter the cortex of the hair shaft through the cuticle — particularly in hair that has been chemically treated, heat-damaged, or mechanically stressed, where the cuticle layer is more open. Once inside, it helps reinforce the internal structure of the strand.

It stays in the hair after rinsing. This is what makes inositol unusual among hair care ingredients. Most conditioning agents are rinsed away with water. Research has shown that inositol remains deposited in the hair shaft even after rinsing — meaning its protective effect continues between washes. This "substantivity" is why regular rice water use produces cumulative benefits over time rather than a single-use effect.

The practical outcomes are reduced friction between strands, reduced static, smoother cuticle surface, and improved resistance to breakage from brushing and styling.

Why fermented rice water is more effective

Plain rice water and fermented rice water both contain inositol and the other beneficial compounds — but fermentation changes the water in two meaningful ways.

Lower pH. The natural pH of healthy hair is between 4.5 and 5.5. Plain rice water has a pH that is higher than this range. Fermentation produces organic acids that lower the pH of the rice water to a level much closer to hair's natural pH. Applying a liquid with the correct pH helps the cuticle lie flat — which reduces frizz, adds shine, and reduces moisture loss from the hair shaft.

Higher concentration of beneficial compounds. The fermentation process breaks down some of the starch in rice water into smaller molecules and increases the concentration of vitamins, amino acids, and antioxidants. The resulting liquid is more nutrient-dense than plain soaked rice water.

The Selfwise Rosemary & Rice Water Hair Growth Spray uses fermented rice water specifically for these reasons — the pH-correcting and nutrient-concentrating effects of fermentation make it a more effective base ingredient than plain rice water.

What the Selfwise formula adds

Fermented rice water is the base — but the Selfwise spray formula adds several ingredients that extend its benefits significantly.

Rosemary extract — steam-distilled rosemary supports scalp microcirculation and has clinical research comparing it to minoxidil for hair growth support. It addresses the follicle level while rice water addresses the hair shaft.

Caffeine — caffeine applied to the scalp has been shown in studies published in the International Journal of Dermatology to penetrate the hair follicle and stimulate hair shaft elongation. It also inhibits the effects of DHT on follicles in laboratory research, making it relevant for those concerned about androgenic hair thinning.

Hydrolyzed keratin — keratin is the structural protein hair is made from. Hydrolyzed keratin has been broken into smaller peptide fragments that can bond to the hair cuticle and fill surface damage, reducing porosity, improving tensile strength, and smoothing the cuticle surface for improved shine and reduced frizz.

Biotin — supports the appearance of thicker-looking strands. Biotin deficiency is associated with hair thinning; while topical biotin absorption is limited compared to dietary intake, it contributes to the overall conditioning profile of the formula.

Aloe vera — soothes and hydrates the scalp, reduces itching and irritation, and adds slip to the formula for improved manageability.

Vitamin C — antioxidant protection against environmental stressors including UV exposure and pollution that can degrade hair protein and cause colour fading and dullness over time.

Who is rice water best for?

✓ Best for: Dry, damaged, chemically treated, or heat-stressed hair — anyone with breakage-prone or high-porosity hair — those wanting improved shine and manageability — all hair textures including straight, wavy, curly, and coily

✗ Not for: Those looking for a standalone hair growth treatment without addressing damage first — anyone with very low-porosity hair may find protein-based treatments cause buildup (monitor and adjust frequency)

How to use rice water for hair

The Selfwise Rosemary & Rice Water Hair Growth Spray can be used three ways:

Daily scalp treatment: Spray directly onto the scalp in sections, massage gently with fingertips, and leave in. No rinsing required. This delivers the rosemary and caffeine to the follicle level consistently.

Leave-in after washing: Mist over damp hair after washing and towel-drying. Distribute through the lengths and ends — do not rinse. This delivers the fermented rice water, keratin, and aloe to the hair shaft while it is most receptive.

Pre-wash treatment: Apply to dry hair before shampooing, leave for 15 to 30 minutes, then wash as normal. This allows the inositol and keratin to penetrate before the mechanical stress of washing.

For best results, combine the scalp treatment and leave-in methods — spray the scalp daily and mist through the lengths after each wash.

Common questions about rice water

Does rice water actually grow hair?

Rice water strengthens existing hair and reduces breakage — which means less hair is lost to mechanical damage, and hair appears to grow longer and fuller over time. This is distinct from stimulating new growth from dormant follicles. For follicle-level growth support, rosemary oil and caffeine (both present in the Selfwise spray) have stronger direct evidence.

How often should I use rice water on my hair?

Daily scalp application and post-wash leave-in use are both suitable for most hair types. For high-porosity or very damaged hair, start with every other day and increase frequency based on how your hair responds. Very low-porosity hair may need less frequent protein treatment — monitor for signs of stiffness or brittleness, which indicate protein overload.

Can I make rice water at home?

Yes. Soak 100g of uncooked white rice in 500ml of water for 30 minutes, strain, and use the liquid as a rinse or spray. For fermented rice water, leave the strained liquid at room temperature for 24 to 48 hours before using. Home-made rice water does not contain the additional active ingredients — rosemary, caffeine, keratin, biotin — present in the Selfwise formula.

Is rice water safe for colour-treated hair?

Yes. Rice water is gentle and does not strip colour. The pH-correcting effect of fermented rice water may actually benefit colour-treated hair by helping seal the cuticle after colouring, which reduces colour fade and improves shine.

How long until I see results?

Improvements in shine and manageability are typically noticeable within 1 to 2 weeks of consistent use. Meaningful reductions in breakage and improvements in hair thickness are typically reported at 4 to 8 weeks. Hair growth results from the rosemary and caffeine components require 3 to 6 months of consistent use.

Selfwise products with rice water

Rosemary & Rice Water Hair Growth Spray — fermented rice water with rosemary extract, caffeine, hydrolyzed keratin, aloe vera, biotin, and vitamin C. Leave-in spray, no rinsing required. Available in 4oz and 12oz.