Rice water.

"Rice water can be nourishing for the scalp skin, and healthy skin provides fertile ground for healthy hair follicles, but we still need more studies. Fermented rice water theoretically is supposed to help your scalp microbiome, but there are cases where it could throw off your scalp microbiome. It might help your hair look healthier, but it's not like a guaranteed growth treatment. I don't think it should replace your tried-and-true medical therapies that we know work. If you're dealing with real hair loss, I wouldn't just bank everything on rice water."

"Promoting any type of rosemary oil, castor oil, or rice water to grow your hair, I would say at best there's strong anecdotal evidence for these things, but if you look at the scientific literature these oils don't really seem to help. I feel like these types of interventions are sort of like a coverup or a way to buy time as your hair naturally starts to regrow. A lot of people turn to things like rosemary oil and castor oil after they have a big shed event in their life, for example after childbirth or a big physical stressor or emotional stressor. Several months later you will have something called telogen effluvium in which you will lose a lot of hair very quickly. Now that is not a permanent hair loss, your body will naturally start to regrow that hair and stop shedding over the course of a year. But I also find that that is the timeline when people are reaching for rosemary oil or castor oil to regrow their hair, and yes they are applying it and yes their hair is regrowing, but it's unlikely to be from the oil itself and much more likely to be due to your natural physiologic processes."