Is the serum suitable for fine hair, or will it weigh it down? — The Doctor. Maximum Energy Keratin, Arginine, and Biotin Hair Serum, 89 ml

The serum is aimed primarily at fine and weakened hair — this is stated directly in its purpose. The light leave-in texture was chosen specifically so as not to create the weighed-down effect typical of heavy oils and nourishing creams.

The hydrolysed keratin in the formula is keratin broken down into small fragments. It is this form that allows it to spread evenly over the surface of the hair without sticking strands together or making them heavier. The effect is a visually denser and smoother strand without loss of movement.

The moisturising ingredients — glycerin, betaine and urea — work at the level of the scalp and the hair surface, retaining moisture. This matters for fine hair: an over-dried strand becomes even more brittle and prone to static, while light moisturising helps keep it elastic without weighing it down.

In practice, a small amount of the product is enough for fine hair. Apply a small amount evenly to the scalp, massage in gently and distribute along the lengths with a comb — as described in the directions for use. If your hair is very fine, it is best to use a minimal amount for the first few applications to find the right quantity for your hair type.

The serum is also relevant after colouring or heat styling — these are the procedures that most often thin the hair structure and make it more brittle.