Making onion hair oil at home requires just a few onions, a carrier oil, and about 30 minutes of hands-on time. The basic formula is simple: infuse chopped onions into a heated carrier oil, strain, and store. A small clinical study published in the Journal of Dermatology found that topical onion juice produced visible hair regrowth in 87% of participants with patchy hair loss after six weeks of twice-daily use, likely due to the high sulfur content in onions that supports the proteins your hair is built from.
What You Need
The core ingredients are 2 to 3 medium red or white onions and about 1 cup (240 ml) of carrier oil. Coconut oil is the most popular base because it penetrates the hair shaft well and is easy to find. Sesame oil works if you prefer a lighter feel, and sweet almond oil is a good option for sensitive scalps. You can use a single carrier oil or blend two together.
Optional add-ins that complement the onion infusion:
- Curry leaves (a small handful): rich in antioxidants that support scalp health and may help reduce premature greying
- Fenugreek seeds (1 tablespoon): traditionally used to strengthen hair and reduce breakage
- A few drops of essential oil (lavender, rosemary, or peppermint): added after cooking to help mask the sulfur smell
You’ll also need a heavy-bottomed pan, a fine mesh strainer or cheesecloth, and a dark glass bottle for storage.
The Slow-Cook Infusion Method
This is the most reliable method for a potent, shelf-stable oil. It extracts the sulfur compounds from the onion directly into the oil while cooking off excess moisture that could cause spoilage.
Peel and roughly chop 2 to 3 onions. You can grate them or pulse them in a food processor for a finer texture, which releases more juice and speeds up the infusion. Add the chopped onion to your pan along with 1 cup of carrier oil. If you’re using curry leaves or fenugreek seeds, add them now.
Heat the mixture on the lowest flame your stove allows. You want a very gentle simmer, not a fry. Small bubbles should appear as the moisture from the onion evaporates. Stir occasionally. After 20 to 30 minutes, the onion pieces will look dry, shrunken, and lightly browned. The oil will have taken on a golden or amber color. That’s your signal to turn off the heat.
Let the oil cool completely, then strain it through cheesecloth or a fine mesh strainer into a clean bowl, pressing the solids to extract every drop. If you want to add essential oils for fragrance, stir in 5 to 8 drops now while the oil is still slightly warm. Pour the finished oil into a dark glass bottle.
The Onion Juice Blend Method
If you want a quicker option that skips the cooking, you can blend raw onion juice directly into a carrier oil. Grate or blend 2 onions and squeeze the pulp through cheesecloth to collect the juice. Mix this juice with carrier oil at a 1:3 ratio, so for every tablespoon of onion juice, add 3 tablespoons of oil. Shake well before each use.
The trade-off is shelf life. Because this version contains raw juice with water content, it needs to be refrigerated and used within 3 to 4 days. The slow-cook method lasts much longer because the heating process removes moisture. If you’re making oil to use regularly over weeks, the cooked version is the better choice.
Storage and Shelf Life
Store your finished oil in a dark-colored glass bottle, away from heat and direct light. Oil oxidizes and turns rancid faster when exposed to either. The slow-cooked version, kept in a cool, dark cabinet, typically stays good for 3 to 4 weeks. Refrigerating it extends that further. Coconut oil will solidify in the fridge, so just let the bottle sit at room temperature for a few minutes before use, or hold it under warm running water.
Sterilize your storage bottle before filling it. Wash it thoroughly with hot soapy water and either boil it for 10 minutes or rinse it with rubbing alcohol and let it air dry. This prevents bacteria and mold from shortening the oil’s usable life.
How to Apply It
Use onion hair oil 2 to 3 times per week. Daily use isn’t necessary and can irritate some scalps. Part your hair into sections and apply the oil directly to your scalp with your fingertips or a dropper, then massage in circular motions for 3 to 5 minutes to improve blood flow. Work any remaining oil through the lengths of your hair if it tends to be dry.
Leave the oil on for at least 45 minutes. If your scalp handles it well, you can leave it on overnight with a towel over your pillow. People with sensitive or oily scalps should stick to 45 to 60 minutes. Wash it out with a gentle shampoo, lathering twice if needed to fully remove the oil.
The clinical study on onion juice showed initial regrowth starting at two weeks, with the most significant results appearing between four and six weeks. Consistency matters more than the amount you use in a single session.
Dealing With the Smell
The sulfur compounds that make onion oil effective are also responsible for the smell, so some odor is unavoidable. The slow-cook method produces a milder scent than the raw juice method because heat breaks down some of the more volatile compounds. Adding rosemary or lavender essential oil helps, but the most effective fix happens at the washing stage.
After shampooing out the oil, rinse your hair with diluted apple cider vinegar: 2 tablespoons in 1 cup of water, poured over your scalp. The acidity neutralizes the sulfur compounds rather than just masking them. Leave it on for 2 to 3 minutes, then rinse with plain water. A diluted lemon juice rinse works similarly. Don’t use the vinegar rinse every single wash, as frequent use can disrupt your scalp’s natural balance.
Strong brewed black coffee, cooled and used as a final rinse, also does a good job of neutralizing the smell.
Patch Test Before Your First Use
Onion oil can cause contact dermatitis in some people, especially those with sensitive skin. Before applying it to your entire scalp, do a patch test. Apply a small amount of the oil to the inside of your forearm or the bend of your elbow and leave it on for 24 hours. If you notice redness, itching, burning, or any swelling, don’t use the oil on your scalp. If there’s no reaction after a full day, you’re good to go.