While scalp massagers seem like they’d be pretty low risk, they are kind of polarizing in the trichologist community. Most of the reasoning against scalp massage comes from two factors: that people tend to use them too aggressively and that they are sometimes thought to be solutions to some scalp issues when, in fact, they can make them worse. “Using such a device on any kind of weakened hair and scalp will only lead to damage and hair loss,” says hairstylist, trichologist and founder of BioMethod Shann Christen.
“For instance someone who is only washing their hair once a week has oil build up inside the follicle. This build up weakens the hard Keratin that holds the papilla in the scalp. Such aggressive action of the scalp massager will only aid in the hair falling from the scalp. Also, someone suffering from Male Pattern Hair Loss is experiencing the miniaturization of the hair shaft. In this weakened state, a scalp massager will only cause the hair to fall from the follicle. Again, the action is too aggressive to be healthy for the hair and scalp.”
Original Source: https://www.menshealth.com/grooming/g45322405/best-scalp-massagers/