Head and shoulders is an a shampoo which helps in mild dandruff. You will notice that historically, one of the main ingredients in it for dealing with dandruff had been zinc pyrithione. Now if you are to read the ingredients, zinc pyrithione is not there.
This is due to a Europe wide directive that came into effect on 1st March 2022 which banned the ingredient in shampoos. The ban in the EU comes from concerns over zinc pyrithione’s potential to affect reproductive health and fertility and concerns for the environment (specifically its impact on water-based ecosystems).
In 2018, the Risk Assessment Committee (RAC) of the European Chemicals Agency (ECHA) categorized zinc pyrithione as having “Reproductive Toxicity 1B” after its evaluation and started the process of banning it. As there are other alternatives in the market, this ban came into action. The UK followed and banned the ingredient.