Does Rosemary Oil Really Grow Hair?

Researched and written by Curl Centric. Read by an AI voice.

The main study behind rosemary oil was done on 100 men with pattern hair loss, and it never measured length. We explain what it can and can't tell you about your hair.

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The full guide, with every source: Rosemary oil for natural hair.

Transcript

This is Curl Science by Curl Centric.

If you've spent any time looking for ways to grow your hair, you've seen rosemary oil recommended just about everywhere. And there's real research behind it, which is more than a lot of viral hair ingredients can say. In this episode, we'll tell you what that research tested, who was in it, and what it can and can't tell you about your hair.

Here's the short version. The main human evidence behind rosemary oil comes from one study. It was done on men losing their hair, ran for six months, and never measured anyone's hair length. So whether rosemary oil is worth your time depends on which problem you're actually having.

Let's look at the study itself. It was published in 2015. Researchers recruited 100 men between 18 and 49 who had androgenetic alopecia, which is the medical name for pattern hair loss. Fifty of them put a topical rosemary oil treatment on their scalps. The other fifty used 2 percent minoxidil, a hair regrowth treatment you can buy without a prescription. Both groups applied their treatment twice a day for six months.

The researchers photographed each man's scalp at the start, at three months, and at six months, and counted his hairs.

At three months, nothing had changed in either group. At six months, both groups had significantly more hair than they started with. The researchers did not find a significant difference in hair counts between the groups at three or six months.

That last sentence is where the headline comes from. In this study, hair counts improved in both groups, and the researchers did not find a meaningful difference between them. That does not prove rosemary oil and minoxidil work equally well, but it explains why they are often compared.

Now here's the part that decides how much weight you give it. There was no third group. Nobody in the study went without treatment, and nobody used a look-alike treatment with no active ingredient, which is normally how researchers separate a real effect from everything else that can happen over six months.

That isn't a reason to throw the study out. Minoxidil has been tested against inactive treatments many times, so comparing rosemary oil with minoxidil does tell us something. A 2025 analysis pooled 24 trials to compare 15 hair-loss treatments against each other, and rosemary oil was one of them. But all the rosemary evidence in that analysis still came from this one study of 100 men.

Which brings us to the question that matters most for your hair: who was in it.

Every man in that study had pattern hair loss. With pattern hair loss, your follicles slowly shrink, so each new strand comes in finer and shorter than the last. Eventually, some follicles may stop producing hair you can see. In men, it often shows up at the temples and crown. In women, it commonly shows up as a widening part, overall thinning, or a ponytail that feels less full.

That's a specific medical condition. It isn't what most of us mean when we say our hair won't grow.

So here's how to use the study. If your part has been getting wider, your hairline has been moving back, or your ponytail feels thinner than it used to, it's worth seeing a dermatologist to find out what's causing it. If you decide to try rosemary oil, remember that this study included only men with pattern hair loss.

If you have a full head of hair and what you want is more length, this study has nothing to say about that. It never measured anyone's length. It counted hairs on scalps that were losing them.

And length is a different problem with a different answer. Your hair grows from your scalp at a fairly steady rate. What changes is how much of that hair is still attached at the end of the month. Your length is what you grow minus what breaks off, and for many curly girls, breakage is what keeps their hair looking stuck at the same length.

Before we get to the practical part, one quick ask. If this is the kind of answer you want, follow the show, so the next one reaches you.

Let's talk about using rosemary oil safely, because rosemary essential oil is concentrated. It should be diluted in a carrier oil, which is a plain oil like jojoba or grapeseed. Don't put rosemary essential oil directly on your scalp.

And natural doesn't always mean gentle. In that same study, scalp itching increased in both groups, including the rosemary group. It was more common with minoxidil, but rosemary oil still irritated some scalps.

So patch test your diluted mixture first. Put a little on a small area of skin and watch it for the next day or two. If your skin or scalp burns, itches, turns red, or starts flaking, stop using it.

If you do want to try it, don't expect a quick result. The study used a specific topical rosemary treatment twice a day for six months, and nothing had changed at the three-month mark. A rosemary oil mixture you make at home may not be the same strength or formulation, so follow the directions on your product rather than trying to copy the study yourself.

One more thing, and please don't skip it. Hair coming out in clumps, a bald patch, a sudden jump in shedding, or a scalp that burns or stays sore may point to something other than pattern hair loss. No oil can diagnose or treat every cause, so make an appointment with a dermatologist.

So, putting it together. The main human evidence comes from one study. It ran for six months, included 100 men with pattern hair loss, and found that hair counts improved with both rosemary oil and 2 percent minoxidil. The researchers did not find a significant difference between the groups, but one small study is not enough to prove the treatments work equally well.

If your hair is thinning, rosemary oil may be worth discussing with a dermatologist or trying carefully. If your hair is healthy and you just want it longer, the study doesn't show that rosemary oil will help. Keeping your ends from breaking will do more for the length you see.

If length is what you're after, we made you a free guide: the seven most common causes of breakage and the weekly routine that helps you stop them. You'll find it at curlcentric.com/keep-the-length, and the link is in the show notes.

That's it for this episode. If it helped, follow Curl Science in your podcast app so the next one reaches you, and leave us a rating while you're there. Curl Science is researched and written by the Curl Centric team, and it's read by an AI voice.