A newcomer to this site so I really don't know how it works. . I was diagnosed last August with Grovers and nothing prescribed or recommended relieved the symptoms. Blood work showed I was deficient in vitamin D3. I started 2000ius a day and within two weeks the GD cooled down and disappeared. The systoms returned this April while self isolating because of Covid-19. I went to 5000 Ius of D3 daily and again the symptoms faded. My dermotolgist poo-poos my findings but for what it may be worth, this is my experience.