What is the ruling on using cans called Toppik, Gofybr, and others on hair, knowing that they are neither hair nor tattoos?

It is permissible to use the aforementioned material, which is hair filings or a protein substance, for the treatment of baldness and hair loss, provided that the materials are pure and harmless. This falls under the category of treatment and removing a defect, just as the Islamic Fiqh Academy permitted hair transplantation for this purpose.

If the material is not made of hair, it is permissible to use it to thicken hair and promote its growth, provided that it is pure and harmless. Its ruling would be similar to that of creams and oils.

As for ghusl (ritual bath), the presence of this material is not valid because it prevents water from reaching the skin beneath it. Therefore, it must be removed before ghusl. However, the matter is easier for wudu (ablution).