Onion Bulb Extract (Allium Cepa)

Onion juice for hair is one of the oldest kitchen rituals in hair care. Here's what onion bulb extract actually does, how to use it without the smell, and answers to common questions.

What is onion bulb extract?

Onion bulb extract comes from Allium cepa — the same onion in your kitchen, concentrated for cosmetic use. It's rich in sulfur-bearing compounds and antioxidants. On our labels, it appears as Allium Cepa (Onion) Bulb Extract.

What onion does for hair

Onion's tradition is about scalp care: a fresh, stimulated-feeling scalp that's been given a conditioning boost. In our formulas, onion bulb extract supports the look of stronger-feeling strands and a comfortable, cared-for scalp — without the blender.

Studied with real people

The complete As I Am Onion regimen — Onion Water daily with Shampoo + Conditioner every three days — was evaluated in an 84-day clinical study of 30 participants, with results compared with baseline.

• In the measured results, hair shedding decreased by 25%, hair density increased by 6.4%, and follicular density increased by 11.1% on average over 84 days.*
• In the consumer questionnaire, 83% said their hair felt stronger at the roots and 83% said their hair looked thicker after 84 days.*

These are results observed in the study — individual results may vary. See the full study results on the Onion Water page.

*Observed results from an 84-day clinical study of 30 participants using the complete As I Am Onion regimen; individual results may vary.

Why we use onion

Our founder, Dr. Ali N. Syed, built As I Am on rituals that communities trusted long before they were formulated in a lab. Onion hair care was one of them. We made it modern: the same idea, refined into a ready-to-use system that leaves your hair fresh — not farm-fresh.

Onion juice vs onion water vs onion oil

• Onion juice is the traditional DIY — blended, strained, and potent (and memorable).
• Onion water for hair is our ready-made scalp mist: the tradition, minus the prep and the smell.
• Onion oil for hair blends onion with carrier oils for massage and sealing.

How to use the onion system

1. Daily refresh: mist Onion Water on scalp and roots; massage lightly.
2. Wash day: cleanse with Onion Shampoo, condition, follow with onion leave-in.
3. Weekly: pay extra attention to edges and braids — mist, massage, move on.

Sensitive scalp? Patch-test first.

Where to find onion

Onion stars across the collection: Onion Water, Onion Shampoo & Conditioner, and the Onion Collection. It belongs to our water family alongside rice water and rosemary.

What the research says

Onion hair care has more published research behind it than most kitchen rituals. Here's what exists — and what doesn't — with links to read for yourself.

• The classic study: Sharquie & Al-Obaidi, The Journal of Dermatology (2002) — in a small clinical study (23 people with patchy alopecia areata), crude onion juice produced regrowth in about 87% of the treatment group versus about 13% with tap water. Read it
• The sulfur story: Chakraborty et al. (2022) — a review of Allium cepa's bioactive compounds: onion's organosulfur compounds and polyphenols drive its studied antioxidant activity. Read it

Note the gap: the published literature covers raw onion juice in a specific scalp condition — the evidence for our formulated system comes from our own 84-day study (above).

How to read this: these studies investigate the ingredient, not our specific formulas. Most are early-stage — small groups, different preparations, and some in cells or animals rather than people. We share them so you can follow the science yourself. Nothing here is medical advice, and no cosmetic product treats or cures a scalp condition. If thinning or loss is your concern, talk to a dermatologist.

The technical details

Onion's edge is sulfur. Here is the chemistry behind the folk remedy.

• Organosulfur compounds: crush an onion and enzymes build sulfur-rich molecules. These are the bulb's defense system — and the root of its hair reputation.
• Sulfur and keratin: hair is keratin, a protein stitched together by disulfide bonds. Those bonds are sulfur links. Sulfur is a structural part of hair, not a bonus.
• Quercetin: red onions carry this flavonoid antioxidant. In ex vivo studies, red onion juice and isoquercetin showed measurable increases in hair growth.
• The measured study: 84 days, 30 participants, the full regimen. Numbers and footnotes are above.

Onion FAQs

Does onion juice help hair growth?

Onion juice has a long folk history, and small studies have looked at onion for hair growth. But no topical kitchen remedy is a proven hair-growth treatment — results are limited and mixed. What onion bulb extract reliably brings: conditioning support and a fresh, cared-for scalp feel.

Does onion water smell?

Ours is built for a clean, fresh finish. You may notice a light botanical scent while it dries; it fades and doesn't linger the way raw onion juice does.

Can I leave onion water in?

Yes — our Onion Water is designed as a leave-in scalp mist. Spray, massage lightly, and style as usual.

Is onion extract safe for my scalp?

Onion bulb extract is generally well tolerated. If your scalp is sensitive, patch-test first and start with one or two uses a week.

How often can I use the onion system?

Most people use Onion Water daily-to-every-other-day and wash with the Onion shampoo and conditioner on regular wash days.

How to make onion juice for hair?

Blend a peeled onion, strain the juice through a cloth, and apply to the scalp before washing. It's potent — and it works best as a pre-wash step. Our Onion Water is the refined version.

How to make onion water?

Soak chopped onion in water for a few hours, then strain. It's much milder than raw juice. Our Onion Water is ready to use — no chopping required.

Why did my hair fall increase after using onion juice?

A few extra shed hairs during application is usually mechanical — massage and manipulation loosen hairs already in the resting phase. If shedding continues, stop and see a dermatologist.