There is no scientific evidence to support the idea that baking soda can be used to treat or reverse gray hair. Baking soda is a mild abrasive that can help to remove surface stains and buildup from the hair, but it is not a hair dye or a treatment for gray hair.
In fact, using baking soda on your hair can actually cause damage and dryness. Baking soda has a high pH level, which can disrupt the natural pH balance of the scalp and hair, leading to irritation, dryness, and breakage.
If you're concerned about gray hair, it's best to speak with a hair care professional or a healthcare provider. They can recommend safe and effective treatments for gray hair, such as hair dyes, highlights, or low-level laser therapy, that are backed by scientific research and can help to restore your hair's natural color or create a new look.