Groganics DHT Blocker System 2 A Day Healthy Hair Vitamins. DHT Blocker System uses the natural ingredients to attack, BLOCK and freeze DHT and slowly strengthen the follicle with promotes longer, stronger, thicker and healthier hair for both men and women. The 2 A Day Healthy Hair Vitamin obstructs DHT and promotes hair growth from inside out. Our 2 A Day Healthy Hair Vitamin includes the herb saw palmetto which is used to prevent and treat hair loss.