SINGAPORE - The Health Sciences Authority (HSA) has warned members of the public not to take an illegal sex drug called "Amace for him" which has been found on sale in Singapore.

The drug was tested and found to contain N-cyclopentyl nortadalfil, a potent undeclared chemical ingredient which is similar to Tadalafil - a prescription medicine for male impotence.

The HSA said in a statement on Wednesday that consuming Taladfil and drugs similar to it may cause symptoms including headaches, dizziness, high blood pressure, chest pain and muscle aches.

"Tadalafil and its analogues should not be used by patients with certain medical conditions, including heart problems, or patients who are taking heart medications such as nitrates as fatalities have been reported," the authority said.

It added that Amace for him was found on sale at a shop in Balastier Plaza called Acupoint Pte Ltd. The product was marketed as a health supplement which contains only natural ingredients, including lingzhi, ginseng, cordyceps and wolfberry.

The drug claimed to 'enhance energy level and blood circulation', 'strengthen the immune system for general well-being' and 'arouse the sexual nerves'.

Acupoint has stopped selling the drug on the HSA's instructions.