It does not provide hydration. It provides good cleansing (=it may dry out the hair a little, but for example the Purifying Scalp Mask from Sephora (with AHA inside) leaves the hair much wilder).
Definitely, it needs a good moisturizing mask afterwards (for example the Masque Hydra-Apaisant from Kérastase that is applied directly to the scalp). However, it keeps the roots cleaner.
Each hair follicle has 2-3 hairs and if they are not nourished/cleansed well, they gradually weaken and you end up losing them before they grow long. The glycolic acid in the ingredients helps a lot with cleansing, especially if you use the ampoules against hair loss - it prepares the scalp for treatment.
For its price, it is a good product.

Excellent product for anyone with dry skin. Whenever I don't wear it, I immediately develop itchiness. I recommend it! It leaves a feeling of cleanliness on the scalp. Wonderful

Only the scent is worth it, it doesn't clean the scalp, it rinses off difficultly, and it is also expensive for what it offers... I kept it for about 3 months...

The only positive thing is that it smells perfect. Then:
1. You have to use a lot of product, so it is expensive for the quantity it provides.
2. It rinses off extremely difficult.
3. I did not notice anything from what it promises in 3 months of use