A conditioner for weak or fragile hair with sea buckthorn and peptides, from Natura Siberica.
What this can and cannot do — said plainly
We would rather set expectations honestly than have you disappointed.
Hair is dead. The only living part is the follicle, beneath the skin. Everything above the scalp is keratin that has already been produced and cannot repair itself — which is why split ends can be sealed in appearance but never healed, and why the only permanent fix is scissors.
A rinse-off conditioner has about a minute of contact. Whatever else it contains, no ingredient in it is doing much to the follicle in that time, and claims about growth from a product you wash off should be read with that in mind.
What a conditioner genuinely does for weak hair is nonetheless valuable: it coats the shaft, smooths the cuticle, reduces friction, and provides the slip that lets you detangle without snapping strands. For fragile hair, reduced breakage is the whole game — hair that stops breaking gets longer, and most people who feel their hair "won't grow" are losing it to breakage rather than failing to produce it.
So the growth claim has a grain of truth in it, just not by the mechanism the name implies.
Peptides
Short chains of amino acids — the same building blocks that make up keratin. In a hair product they act largely as film-formers, coating and temporarily strengthening the strand. That is a real effect, and it washes out and needs reapplying.
Using it properly
Mid-lengths to ends. Never the scalp. Squeeze the water out of your hair first, so the conditioner is not diluted before it can bind. Leave a minute or two, then detangle with a wide-tooth comb while it is in — wet hair is at its most fragile and the slip is what prevents breakage. Rinse with cool water.
And handle fragile hair less. Fewer heat tools, looser ties, a silk or satin pillowcase, and no brushing when dry will each do more than any product.