Red Onion Hair Growth Serum 50mlRed Onion Hair Growth Serum 50ml Sulfur Rich Keratin Strengthening The Red Onion Hair Growth Serum by Happy Heads uses one of hair cares most potent natural actives red onion extract to attack hair loss and weakness from a completely different angle than rosemary based serums. Where rosemary targets scalp circulation and DHT, red onion works through a sulfur based keratin building mechanism that directly strengthens the hair structure itself. How Red