Rosemary Essential Oil
Rosemary is a culinary healing herb. Native to the Mediterranean, it has been used as food and medicine for centuries.
As with other essential oils, such as oregano peppermint, and cinnamon, rosemary is commonly found in essential oil form. Essential oils are highly concentrated and distilled extracts of volatile plant compounds used for cooking, cleaning, beauty, health, etc.
Besides hair growth, Rosemary essential oil has a range of antioxidant, anti-inflammation and memory enhancement benefits.
Mediterranean cultures have used rosemary in hair rinses to promote hair growth for hundreds of years. New research has indeed shown that Rosemary Essential Oil could help to prevent hair loss.

A 2015 study compared rosemary oil to minoxidil. People with DHT-related hair loss received either rosemary oil or minoxidil for 6 months. By 6 months, both groups saw significant increases in hair growth.
The group that was treated with Rosemary Essential Oil actually had marginally more hair growth than the minoxidil group. This result suggests that rosemary oil may promote hair growth in the long term.
Research: https://hairgenx.co.za/scientific-research-for-thinning-hair/ para 9.