Nirvel Professional Technica Pack Keratinliss Fuerte is a keratin straightening programme that helps to keep hair straight and shiny for longer. It helps to eliminate frizz and unwanted curl or waves from the hair, helping to increase shine and provide a silky texture. Its main active ingredient is keratin, a protein that helps to reconstitute and regenerate the hair fibre, helping to moisturise the hair. The duration of the straightening is 3 to 4 months. The pack includes a pre-treatment shampoo, a straightening cream, a balm, a neutraliser, a post-treatment shampoo and a keratin-based mask.