Everything you need to know about rosemary oil for hair
Perhaps you’re wondering whether rosemary oil deserves a place on your bathroom shelf. Let’s take a closer look at what it is and how to use it in your hair care.
In brief
- Rosemary oil is an essential oil distilled from rosemary leaves.
- Rosemary oil is simply the English name for the same oil.
- It has a fresh, spicy scent, a little like rosemary in the kitchen.
- In hair care, it is mostly used in scalp products.
What is rosemary oil?
Rosemary oil is an essential oil distilled from the leaves of the rosemary plant. You’ll recognise the scent if you’ve ever picked a few leaves from the rosemary on your kitchen windowsill.
It is therefore a different type of oil from coconut oil and argan oil. The oil contains concentrated fragrance compounds, which vary from plant to plant.1
Rosemary oil is the English name, and many people write the Danish name as two words. On an ingredient list, you’ll find it as Rosmarinus Officinalis Leaf Oil.
Does rosemary oil work on hair?
Rosemary oil has received a lot of attention on social media, especially when it comes to hair loss. Many people also enjoy the fresh scent while massaging their scalp. You’ll find essential oils in many scalp products, but we still know little about what they do there.2
We don’t yet know whether rosemary oil helps with hair loss. The oil has only been examined in a few small studies, and larger studies are needed before we can say more.3
One frequently mentioned trial included only 100 men with hereditary hair loss. The trial also lacked a placebo group, a group given a treatment with no effect so that the results can be compared.4 You can read more about the trial and its limitations under INCI and studies.
If you’re losing hair, get help finding the cause.
How to use rosemary oil in your hair
Pure rosemary oil must always be diluted. Essential oils are concentrated and can irritate the scalp if you use them undiluted. Choose a ready-made hair product in which the rosemary oil is already diluted.
Follow the instructions for use. They will also tell you how long to leave the product in your hair and whether you can sleep with it in.
- Choose a ready-made hair product rather than pure oil.
- Try the product on a small area of skin for about a week first.
- Keep it away from your eyes.
- Stop if your scalp itches, stings or becomes red. You can still develop an allergy even if your skin doesn’t react the first time you try the product.
When you massage your scalp with your fingertips, you can also enjoy a little moment to yourself.
Talk to your doctor
If you’re pregnant or breastfeeding, ask your doctor or midwife before using essential oils. Also ask your doctor first if you want to use essential oils on children.
Can rosemary oil cause an allergy?
Yes. All fragrance compounds, including those from natural sources such as essential oils, can cause allergies.5 If you’re allergic to one essential oil, you’re often also allergic to others or to fragrance.6
Some people have also developed allergies to the rosemary plant itself and rosemary extract.7 If you have a fragrance allergy, ask your doctor or pharmacist for help reviewing the ingredient list.
If you develop an allergy, you’ll typically experience itching, redness or a rash where you used the product. Stop using the product immediately.
Good to know
An ingredient isn’t necessarily mild just because it’s natural. Natural extracts are actually the most common cause of fragrance allergy.5
Myth or fact?
Natural oils are always mild.
Myth. Essential oils are concentrated and can both irritate the skin and cause allergies.
The more oil, the better.
Myth. Pure rosemary oil must always be diluted. Follow the instructions for use on your product.
The Danish and English names refer to the same oil.
Fact. It is the same oil with a Danish and an English name.
Rosemary oil or rosemary water?
Rosemary water is water in which rosemary leaves have been steeped, a little like a cup of tea. It is much milder than the essential oil.
We’re not aware of any studies on what rosemary water does for hair. If you want to try it, keep it away from your eyes and stop if your scalp reacts.
Can you make rosemary oil yourself?
Not the essential oil. It is distilled, and that requires equipment that most people don’t have in their kitchen.
What many people call homemade rosemary oil is rosemary that has been steeped in an ordinary plant oil. It is not the essential rosemary oil that the studies are about.
A pure plant oil can add shine to your dry lengths. See, for example, what jojoba oil and castor oil can do for hair.
Hair loss: when should you see a doctor?
Hair loss can be hereditary or caused by stress, illness, a fungal infection of the scalp or styling that puts strain on the hair. In many cases, hair loss can be treated.8 That’s why it’s a good idea to have it checked.
See your doctor if you:
- lose a lot of hair in a short time
- develop bald patches
- have itching, redness or dandruff on your scalp
- are worried about your hair
How should you use rosemary oil?
- A few drops of pure oil directly on the scalp
- In a ready-made hair product where the oil is diluted
- As much as possible, overnight
Pure rosemary oil is concentrated and must always be diluted before you use it on your skin.
Your scalp itches after using a new product. What do you do?
- Keep using it, as it will probably pass
- Stop using the product
- Use a little more
Itching, redness and stinging are signs that your skin isn’t tolerating the product.
Are rosemary oil and rosemary water the same?
- Yes, they’re two names for the same thing
- No, rosemary water is much milder
- No, rosemary water is stronger than the oil
Rosemary water is water in which the leaves have been steeped. The essential oil is concentrated.
Care for dry hair and scalp
At ECOOKING, we don’t sell rosemary oil. Give your hair and scalp some care with a mild shampoo. Use conditioner on the lengths, and treat your hair to a hair mask when it feels dry.
Find care for dry hair, or see our hair oil and hair mask. If you’d like to know more about oils for hair and skin, compare oils for the skin.
Frequently asked questions
Does rosemary oil work on hair?
We don’t yet know whether rosemary oil helps with hair loss. If you’re losing hair, have the cause investigated.
How do you use rosemary oil in your hair?
Choose a ready-made hair product with rosemary oil rather than pure oil, and follow the instructions for use. Try the product on a small area of skin first and keep it away from your eyes.
Does rosemary oil need to be diluted?
Yes, always. Pure rosemary oil is concentrated and can irritate the skin and cause allergies. In a ready-made product, it is already diluted.
Can you sleep with rosemary oil in your hair?
Never with undiluted rosemary oil. If you’re using a ready-made product, check the instructions for use to see whether it can be left in your hair overnight.
Can rosemary oil cause an allergy?
Yes. Essential oils can cause allergies, and some people have also developed an allergy to rosemary. If you have a fragrance allergy, ask your doctor or pharmacist for help reviewing the ingredient list.
What is the difference between rosemary oil and rosemary water?
Rosemary oil is a concentrated essential oil distilled from the leaves. Rosemary water is water in which the leaves have been steeped, and it is much milder.
Can you make rosemary oil yourself?
Not essential rosemary oil, because it has to be distilled. Homemade rosemary oil is usually rosemary that has been steeped in a plant oil. It is not the same as essential rosemary oil.
Sources
- Satyal P et al. Chemotypic Characterization and Biological Activity of Rosmarinus officinalis. Foods. 2017. PubMed
- Abelan US et al. Potential use of essential oils in cosmetic and dermatological hair products: A review. Journal of Cosmetic Dermatology. 2022. PubMed
- Ahmed A et al. Herbal Remedies for Hair Loss: A Review of Efficacy and Safety. Skin Appendage Disorders. 2025. PubMed
- Panahi Y et al. Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial. Skinmed. 2015. PubMed
- Videncenter for Allergi. Fragrance. videncenterforallergi.dk
- de Groot AC, Schmidt E. Essential Oils, Part IV: Contact Allergy. Dermatitis. 2016. PubMed
- Miroddi M et al. Rosmarinus officinalis L. as cause of contact dermatitis. Allergologia et Immunopathologia. 2014. PubMed
- Phillips TG et al. Hair Loss: Common Causes and Treatment. American Family Physician. 2017. PubMed
