What is the ruling on henna that prevents hair loss and nourishes the hair if it gives it a black color?

If henna is treated to give a black color, it is impermissible to use it because it falls under the meaning of dyeing with black. However, if hair loss leads to disfigurement and no other treatment is available, then it is permissible out of necessity. But if it is in its natural form and not treated, there is no objection to using it, even if it results in a black color, because the prohibition was mentioned regarding pure black dye, provided that this does not lead to deception of a suitor.