Rosemary for Hair: What We Know So Far

Rosemary oil for hair growth is everywhere: videos of homemade rosemary water, scalp oils, shampoos and, more recently, capsules that include rosemary extract. Many women with thinning hair are understandably curious.

So what is the evidence? In short: there is a small but interesting amount of research, a lot of enthusiasm and plenty of unanswered questions. Here is a careful look.

The study behind the buzz

Most rosemary claims trace back to one study: a randomized trial published in 2015 in the journal Skinmed.

What the researchers did

• 100 people with androgenetic alopecia (pattern hair loss) were randomly assigned to use either rosemary oil or 2% minoxidil on the scalp.
• The study lasted six months.
• Hair counts were measured with standardized photographs at the start, at three months and at six months.

What they found

• At three months, neither group showed a significant change in hair count.
• At six months, both groups had a significant increase in hair count compared with the start.
• There was no significant difference between rosemary oil and minoxidil at either time point.
• Scalp itching increased in both groups, but was more common with minoxidil.

Why it is not the final word

This study is genuinely interesting, but it has important limitations:

• It was small. One hundred participants is a modest number for drawing firm conclusions.
• There was no placebo group. Without one, we cannot be sure how much improvement came from the treatments themselves versus other factors.
• It compared rosemary with 2% minoxidil. For women, both 2% and 5% minoxidil are used; the comparison does not tell us how rosemary stacks up against all options.
• It has not been widely replicated. One trial, even a well-run one, needs confirmation from larger, independent studies.
• It tested topical oil. The participants applied rosemary oil to the scalp. The findings do not tell us anything about rosemary taken by mouth in capsules.

This last point matters because several hair supplements now include rosemary extract. Results from a scalp oil study cannot be assumed to apply to an oral product.

How rosemary might work

Researchers have suggested a few possible mechanisms, such as improving blood flow to the scalp and anti-inflammatory or antioxidant effects from compounds like carnosic acid and rosmarinic acid. These ideas come mainly from laboratory and animal studies and have not been confirmed in humans.

How people use rosemary oil

If you want to try rosemary oil after talking to your clinician or dermatologist, here are common practices and safety tips:

• Always dilute essential oil. Concentrated essential oils can irritate the skin. People typically mix a few drops into a carrier oil, such as jojoba or coconut oil.
• Patch test first. Apply a small amount to the inside of your forearm and wait 24 to 48 hours to check for redness or itching.
• Massage gently into the scalp, then leave it on for a period before washing, according to the product directions.
• Be consistent and patient. In the study, changes were not seen until six months.
• Keep it away from your eyes.

Ready-made rosemary hair products vary enormously in concentration and quality, and many have never been tested.

Safety considerations

Rosemary used in cooking is safe. Concentrated forms need more care:

• Skin irritation and allergic reactions are possible with essential oils.
• Pregnancy and breastfeeding: concentrated rosemary products are not recommended without medical advice.
• Seizure disorders: high doses of rosemary may be a concern; talk to your clinician.
• Do not swallow essential oils. They can be toxic when ingested.

If you are considering an oral supplement that combines rosemary with other ingredients, look carefully at everything on the label. For example, green tea extract and turmeric are common in hair formulas. The National Center for Complementary and Integrative Health notes that green tea extract supplements have been linked with rare cases of liver injury, and NCCIH also reports rare liver injury associated with turmeric supplements. Discuss multi-ingredient supplements with your clinician, especially if you take other medications.

Remember too that, as the FDA explains, supplements are not reviewed for safety and effectiveness before they are sold. NCCIH's guide to using dietary supplements wisely is worth reading before you buy.

How rosemary compares with proven options

The American Academy of Dermatology describes minoxidil as a treatment that can help women with female pattern hair loss. It is reasonable to talk with a dermatologist about whether minoxidil, rosemary or both make sense for you, but do not abandon an effective treatment for an unproven one.

The most important step: know your cause

Hair thinning can have many causes, from female pattern hair loss to thyroid problems, low iron, stress and medications. Mayo Clinic lists a wide range. Rosemary will not fix thinning caused by a thyroid problem or iron deficiency. A proper diagnosis helps you choose a treatment that targets the real issue. See hair thinning after 40 for more.

The bottom line

Rosemary oil is a promising but unproven option for hair thinning. One small 2015 trial found that rosemary oil on the scalp performed similarly to 2% minoxidil after six months, but that study had no placebo group and has not been widely replicated, and it says nothing about rosemary capsules. If you want to try topical rosemary, dilute it, patch test and be patient. For female pattern hair loss, minoxidil remains the better-studied choice, and a dermatologist can help you find the right plan.

Frequently asked questions

Does rosemary oil really regrow hair?

One small randomized trial found that rosemary oil applied to the scalp increased hair counts after six months, similar to 2% minoxidil. More research is needed to confirm the results.

How long does rosemary oil take to work?

In the 2015 study, no significant change was seen at three months, and improvements appeared at six months.

Do rosemary supplements work for hair?

There is no good evidence that rosemary taken by mouth helps hair growth. The main study tested oil applied to the scalp.

Is rosemary oil better than minoxidil?

There is not enough evidence to say so. One small trial found similar results, but minoxidil is FDA-approved and has been studied far more extensively.