Do those pills that claim to prevent and reverse gray hair really work at all? What about a chinese tonic called shou wu chih/ho shou wu? What can actually prevent and reverse gray hair like many of these guys are claiming?? Does anyone know? What can actually prevent and reverse gray hair?? Anyone?

No they do not. Gray hair is caused by different factors but a trip to your hair stylist for color is about the only cure

THere is no "cure" for grey hair, that's why there's hair dye, because that's the only solution to cover grey hair.