The short answer
Rosemary oil for hair is usually an infused oil. You steep dried rosemary in a carrier oil, either slowly for about a month or gently with heat in a double boiler, then strain it and store it in a dark bottle. You need no special equipment.
Infused oil or essential oil?
These two get mixed up a lot online.
Rosemary essential oil is a concentrated extract made by steam distillation. It's very strong and always needs to be diluted before it goes on skin.
Rosemary infused oil is what you make at home. Dried rosemary rests in a carrier oil and passes on its scent and character. It's gentle enough to massage into your scalp as it is. This article is about the infused kind.
What you need
- Dried rosemary
- A carrier oil. Olive, sweet almond, jojoba and sunflower are popular for hair, and each one feels different on the scalp.
- A clean, completely dry glass jar with a lid
- A fine strainer or a piece of cheesecloth
- A dark glass bottle for storing
- For the heat method, a double boiler or a heatproof bowl over a pot of water
Why dried rosemary, not fresh?
Fresh herbs contain water, and water is the enemy of infused oil. Moisture trapped in oil can let mold and bacteria grow, often where you can't see it. Dried rosemary gives you the scent without that risk. If you grow your own, dry it fully before you start.
The slow method (about a month)
- Put the dried rosemary in your jar and pour in enough oil to cover it completely, so no leaves poke out.
- Close the lid and keep the jar somewhere warm, away from direct sun.
- Give it a gentle shake every day or two.
- After about a month, strain it through a fine strainer or cloth and pour it into your bottle.
The slow method gives the fullest scent. It's my favorite when I'm not in a hurry.
The heat method (same day)
- Put the rosemary and oil in a heatproof bowl over a pot of barely simmering water.
- Keep the oil warm, never hot, for a few hours and stir now and then. You want to coax the plant, not fry it.
- Let it cool, then strain and bottle it.
If the oil smells cooked or the leaves turn brown and crispy, the heat is too high.
How to use rosemary oil on your hair
Most people use it as a scalp massage oil before washing. Part your hair, apply a little oil to the scalp, massage for a few minutes and leave it on for a while before you shampoo. Some people also smooth a drop through dry ends.
Start small, and patch test on the inside of your arm first. Even gentle oils don't suit everyone.
Will rosemary oil make my hair grow?
I can't promise that, and I'd be careful with anyone who does. There's some early research on rosemary and the scalp, but it's limited, and most of it looks at rosemary essential oil, not homemade infused oil. What I can say is that a scalp massage with a nice oil is a lovely weekly ritual. If you're worried about hair loss, a dermatologist is the right person to ask.
How long does it last?
Stored in a dark bottle in a cool place, rosemary infused oil usually keeps for several months, depending on the carrier oil you choose. I explain what makes the difference in how long herb-infused oils last.
Go further with infusions
My Oil Infusions guide covers every way to infuse herbs into oil, how to dry your own plants, straining and storage, and two ARKE formulas, including my rosemary scalp and hair oil with how to use it and how often.
This article is for educational purposes only. It does not provide medical advice or replace professional consultation. Written by Yana, who makes and tests every ARKE formula in Phuket, Thailand.
