But taking undiluted rosemary oil or very large amounts of rosemary leaf is likely unsafe. Taking large amounts of rosemary can cause vomiting, sun sensitivity, and skin redness. When applied to the skin: Rosemary oil is possibly safe for most people. It might cause allergic reactions in some people.
Because it's a pretty potent ingredient, for some, excess use of rosemary oil may lead to some itching and burning, says Holdsworth.
Although rosemary oil is not harmful, James warns against leaving it in hair overnight. “Leaving any kind of oil on the scalp for a prolonged period of time will upset the microflora of the scalp,” she says. “This can cause itchiness and redness, and it applies to all oils—not just rosemary oil.”
“Everyone can use rosemary oil, but you might need to modify how often you use it depending on your hair type,” suggests Dr. Khetarpal. “Some people might be able to use it daily. Others may see that one or twice a week works best.”
Because of their volatile oil content, large quantities of rosemary leaves can cause serious side effects, including vomiting, spasms, coma and, in some cases, pulmonary edema (fluid in the lungs).
Does Rosemary Oil Thicken Hair? The short answer is yes. There is some scientific evidence that rubbing rosemary oil into the scalp can help hair growth. One study showed that rosemary oil was as effective as minoxidil at stimulating hair growth.
Yes, you can leave rosemary oil in your hair overnight to reap the benefits while getting some well-deserved rest. However, it is important not to leave directly-applied rosemary oil on the hair overnight, as this can cause irritation. Only ever use diluted rosemary oil or products infused with rosemary oil.
Can I leave rosemary oil in my hair overnight? While it's not harmful to leave rosemary oil in your hair overnight, it may cause irritation to your scalp if you have sensitive skin. Adding a few drops of rosemary oil to a carrier oil, such as coconut or olive oil, can help to dilute it.
Because essential oils can irritate the skin when used on their own, when it's not diluted they can have the opposite effect on your hair, causing hair to fall out. Rosemary oil can be used in a variety of ways depending on your hair's needs.
Put 4-5 drops of rosemary essential oil on your scalp with the help of a dropper and gently massage it in your scalp. Massage it in circular motions to increase the blood flow in your scalp and hence, promote hair growth. Don't apply more than 5 drops of rosemary oil as too much of it can cause your scalp to itch.
How to apply rosemary oil to hair. We recommend leaving rosemary oil in your hair (diluted) from 30 minutes to an hour before washing your hair as usual (though leaving it in your hair from 2 hours all the way up to 6 hours is the most effective). You can repeat this process up to twice a week for best results.
Rosemary oil can be applied directly to your hair strands (it won't cause damage), but it should be massaged into your scalp if you're looking for the potential hair-growth benefits.
Rosemary oil is most effective for hair restoration when used consistently for at least 6 months. You can also use treatments a minimum of 1 to 2 times per week. While research suggests there are health benefits, the FDA doesn't monitor or regulate the purity or quality of essential oils.
However, direct application of rosemary oil on the scalp is not recommended because it may cause itching and irritation in some people. Before applying it to your scalp, dilute the essential oil in jojoba or coconut oil.
Just try to find at least a couple hours to leave the rosemary oil on your scalp before washing it out. If you're pressed for time or don't like the feeling of an oily scalp, you can use what I call the “quick method” to apply rosemary oil.
You can add a few drops of rosemary essential oil with water and use it to spray on your hair or apply it on your skin. You can apply rosemary water directly to your hair and scalp and also use it on your skin.
However, it should never be used directly. Rosemary oil should always be used as an essential oil, and only a few drops should be added to your carrier oil. The reason is that this oil is extremely potent in nature, and if applied directly, whether on the skin or on the hair, can cause burns and damage.
To use it, Henry suggests mixing pure rosemary oil with a carrier oil (like grapeseed or coconut oil), which will help your skin better tolerate the ingredient. Massage the scalp treatment onto your head twice per day. Another option is to use products that feature the oil as an active ingredient, Henry said.
Avoid leaving oil in overnight
The longer, the better — that may be true for some hair treatments but not for hair oiling as the oil can block your hair follicles. Unless an ayurvedic doctor or expert has asked you to leave a medicated oil overnight, wash out the oil within 3-4 hours.
Do I apply rosemary oil to wet or dry hair? The choice is yours! You can apply the solution to wet hair when washing your locks, use it when styling towel-dried hair, or put it directly on dry hair.
Rosemary oil is a powerful antioxidant and can be used to treat many skin conditions, such as eczema, psoriasis and acne. However it has also been known to cause damage to your scalp and follicles if used incorrectly. Rosemary oil can cause inflammation which can lead to hair loss in some cases.
Rosemary Oil Benefits
“It is best known for its antiseptic properties on the scalp, which means it is excellent for eliminating dandruff,” says Darrius Peace, hairstylist and natural hair expert. “In fact, because it can be used on the scalp, the absorption can also aid in muscle relief, providing mental clarity.”
We recommend mixing two tablespoons of carrier oil with two-three drops of rosemary oil. Use this mixture as a hair mask; apply to your scalp and leave on for an hour before washing out.