From claims that it speeds up hair growth and makes it thicker to promises of preventing hair loss and even reversing baldness, a TikTok favourite has been making the rounds online for a couple of years — but experts are warning about its potential side effects.
Dr Gizem, a London-based hair loss specialist, warns that improper usage of rosemary oil can cause hair loss instead of hair growth. “Many people apply rosemary oil to their scalps hoping to get the same results as minoxidil, but as with anything, improper use can do more harm than good.
If you use undiluted rosemary oil to a healthy scalp or make the mistake of applying it to an already irritated scalp, it can potentially harm the skin of your scalp as well as your hair and, in rare cases, result in direct shedding of your hair strands. So, be careful.”
Dr Cagla, a hair transplant surgeon in Istanbul, also agreed, recommending a teaspoon of carrier oil mixed with 2 to 3 drops of rosemary to balance its effects.
Additionally, Dr Gizem warned against overusing the oil in hopes that it might somehow speed up the hair growth cycle: “Moderation is key, and it’s actually better for you if you start with a small amount of rosemary oil and then gradually increase the frequency and duration of its usage. If you use too much of it, it can clog your hair follicles, which might also lead to hair loss.”
Two to three 30-minute applications of rosemary oil per week should be enough, says Dr Cagla.
Notably, Dr Gizem pointed out that, in and of itself, rosemary oil will not cause hair loss, but it can cause some temporary shedding once you begin using it.
“Some people can experience hair loss after starting to use rosemary oil because the oil affects the hair growth cycle. However, in that case, it’s actually a good thing because it’s a sign the oil is stimulating your hair growth and pushing out the older hair,” she added.
To avoid damaging the hair with rosemary oil, Dr Gizem recommends several precautions, including diluting rosemary oil with coconut, castor or jojoba oil as a way to reduce its potency.
However, even if the rosemary oil has been diluted, you shouldn’t consider it completely safe as there’s still a risk of allergic reaction, according to the expert. “Whether or not the rosemary oil has been diluted, it still carries the risk of causing allergic contact dermatitis, which can cause itchiness and dryness, among other symptoms.”
For this, Dr Gizem recommends that the best thing to do is to do a patch test: “Before you apply rosemary oil on your scalp, test it out on a small area of the skin to make sure you don’t have any sensitivity or an allergic reaction.”
Lastly, though many comparisons have been drawn between the effectiveness of rosemary oil and minoxidil, according to the specialist, a specific concentration of minoxidil is still a better alternative.
“Minoxidil is backed by extensive research, and although there is some research showing similar efficacy between rosemary oil and 2% minoxidil, the industry standard 5% minoxidil would still be more effective in comparison.”
Dr Gizem
Dr. Gizem is a facial aesthetics practitioner at Dr Giz Aesthetics, a Medical Aesthetics Clinic in London. She specialises in platelet-rich plasma (PRP) injections, as well as a wide range of non-surgical rejuvenation treatments for the skin, hair, and body. With experience treating over 500 patients, Dr. Gizem is fluent in both English and Turkish.
