I don't know about black hair, because I have no problem with white hair, but I know it is really good for hair loss and long hair. Let's decide whether to use it or not. Personally, I think the authenticity of a product is the most important. If there is a good voice, there will be a bad voice. To tell the truth, both good and bad aspects will make others feel fake, because everyone's needs are different, the definition of effect is different, and the positioning of a brand is different, which means it may not be suitable for everyone. But whether it is useful to yourself or not, you really have to use it yourself to know. Before buying this thing, I also looked up a lot of information and read a lot of comments, saying that there were all kinds of useful and useless voices. But at least one thing is certain: Wenquan is at least not a liar, at least not cheating money like some websites, so I carefully looked at their official website and decided to try it myself after learning more about it. I don't know if it's useful to you, but it's definitely good for me. It took me less than two cycles.