A 2015 study compared the efficacy of rosemary oil as a treatment for hair loss vs. Minoxidil 2%. After 6 months, both groups showed a significant increase in hair count; suggesting rosemary oil is just as effective as Minoxidil in stimulating new hair growth and provides evidence as to the efficacy of rosemary oil to treat hair loss. In addition, far greater scalp itchiness was reported in the Minoxidil group vs. the rosemary group, suggesting that Minoxidil may provide unwanted side effects (at least in terms of itchiness) that rosemary oil does not.

A number of studies have shown promising results with regards to green tea as a treatment for hair loss. It is suggested than "catechins" in green tea (a type of antioxidant) may reduce the amount of "DHT" (dihydrotestosterone - the hair loss causing hormone). In a 2005 study on mice with hair loss, 33% of mice who received a solution containing polyphenols (naturally occurring antioxidants in green tea) showed significant hair re-growth after 6 months. While the group of mice who did not have this solution showed no improvement at all. In a test tube based experiment, polyphenols proved effective in reducing the enzyme that causes DHT. Lastly, in a small study on humans, 80% showed improvements in hair growth after 24 weeks when given a natural supplement including green tea and two other ingredients. Again this suggests benefits of green tea for hair loss, however this trial did include other ingredients so it is difficult to assume the exact efficacy of green tea alone.

In a 2014 study, pumpkin seed oil (PSO) was given to 76 men suffering from hair loss for 24 weeks. At the end of the study, the group receiving PSO showed greater improvements in hair growth vs. the control group (who received a placebo). After 24 weeks of treatment, self-rated improvement score and self-rated satisfaction scores in the PSO-treated group were higher than in the placebo group. The PSO-treated group had more hair after treatment than at baseline, compared to the placebo group. Mean hair count increases of 40% were observed in PSO-treated men at 24 weeks, whereas increases of 10% were observed in placebo-treated men.

In a 1998 study, 86 patients were randomized into two groups. The active group massaged essential oils (thyme, rosemary, lavender, and cedarwood) in a mixture of carrier oils (jojoba and grapeseed) into their scalp daily. The control group used only carrier oils for their massage, also daily. At the end of the study, nineteen (44%) of 43 patients in the active group showed improvement compared with 6 (15%) of 41 patients in the control group. An alopecia scale was applied by blinded observers on sequential photographs which backed up the above findings. The degree of improvement on photographic assessment was significant.

In a 2014 study, mice were randomized into 4 groups based on different topical applications: saline (SA), jojoba oil (JO), 3% minoxidil (MXD), and 3% peppermint oil (PEO). Of the 4 experimental groups, PEO group showed the most prominent hair growth effects; a significant increase in dermal thickness, follicle number, and follicle depth.