Rosemary oil has limited human research related to hair loss, but that evidence does not prove that every product containing rosemary grows hair. The tested preparation, concentration, diagnosis, application schedule and study design all matter.
What one commonly cited human study found
A 2015 randomized comparative trial assigned 100 people with androgenetic alopecia to rosemary oil or 2% minoxidil for six months. Neither group had a significant hair-count change at three months; both groups increased from baseline at six months, with no significant difference between groups. Scalp itching increased in both groups.
What that study does not establish
It does not show that:
• rosemary works for every cause of shedding or hair loss;
• any product listing rosemary has the same composition or concentration;
• a multi-ingredient cosmetic performs like the studied preparation;
• results are guaranteed; or
• rosemary replaces diagnosis and treatment from a qualified clinician.
Ingredient evidence is not finished-product evidence
A formula’s concentration, carrier, stability, manufacturing and directions can change performance and tolerability. Regiment31’s finished products have not been clinically tested for hair regrowth, so ingredient research must not be presented as proof that the products treat alopecia.
Safety and realistic use
“Natural” does not automatically mean non-irritating. Follow the finished product’s directions, avoid applying undiluted essential oil casually, stop use if irritation develops and seek medical care for a severe reaction.
Read What Hair-Growth Products Can and Cannot Do for Curly Hair and our Editorial Standards and Evidence Policy.
Sources: PubMed: Rosemary oil vs. minoxidil 2% randomized comparative trial; FDA: Aromatherapy and essential-oil claims; FDA: Cosmetic versus drug claims.
Reviewed July 2026. This article is educational and is not medical advice. Regiment31 cosmetics are not intended to diagnose, treat, cure or prevent alopecia.