The Consumer Council on Monday urged people to choose anti-dandruff shampoo carefully, after finding EU-banned substances in some products on the market.

The watchdog tested 25 anti-dandruff models and found that four contained zinc pyrithione (ZPT), which is banned in the European Union due to the potential harm to unborn children.

The four brands are HAIR CORNER, Petal Fresh Pure, CLEAR and Philip B.

Gilly Wong, the council’s chief executive, said consumers should identify the root cause of dandruff before buying products.

“When you have dandruff, you have to identify probably what is the reason. Is [your scalp] too oily, or maybe too dry, or other reasons? This is something as a first screening about yourself,” she said.

“But on the other hand, if you have this problem for quite a bit of time, it's much better for you to seek medical advice before you continue to try on different products.”

Over 90 percent of shampoo products also contained fragrance allergens, with two containing the EU-banned chemical BMHCA which can adversely affect both male and female fertility.

However, the watchdog said some products were not labelled at all or only included some fragrance allergens.

The council urged manufacturers to review their formulas and improve labelling transparency.