(TrendHunter.com) In the category of effective, fast-acting reparative shampoo, Olaplex stands out with its N°4. The formula is vouched to repair existing damage and protect from newly occurring one. The... (TrendHunter.com) In the category of effective, fast-acting reparative shampoo, Olaplex stands out with its N°4. The formula is vouched to repair existing damage and protect from newly occurring one. The...