Helping to keep strands hydrated and soothe the scalp, castor oil is commonly found in many hair care products and standalone treatments. Rumors have swirled in online communities that castor oil, much like rosemary oil, not only helps hair look and feel healthier, but it can make it grow faster too. To help investigate these claims, we tapped board-certified dermatologists to better understand castor oil’s benefits, how it works and whether it can truly help with hair growth.

Dr. Dara Spearman, a board-certified dermatologist and owner of Radiant Dermatology Associates in Fort Wayne, Indiana, said you can use this richly textured oil as a deep conditioner to treat damaged hair. Harvested and hand-processed in Haiti, this oil can be used on the scalp, hair, skin and beard for adding extra moisture.

Made with a combination of rosemary, mint, castor and other essential oils, this Mielle treatment helps boost circulation to the scalp, which Dr. Marisa Garshick, a board-certified dermatologist based in New York City, said helps stimulate hair follicles, aiding in hair growth and thickening. Though your results may vary for hair growth, this under-$10 oil is an affordable option for those curious to try castor oil for themselves.