A brand of "energy pills" containing an erectile dysfunction drug should not be taken and poses a "serious" risk to heath, the Therapeutic Goods Administration has said.
The TGA issued the warning over HERO Instant Energy for Males capsules today.
Testing revealed the pills contained Taladafil, which is also known as Cialis, and is used to treat erectile dysfunction.
However, the HERO pills do not declare the presence of Taladafil, the TGA said.
The substance can interact with nitrates found in some prescription medicines, and can lower blood pressure to dangerous levels.
People with diabetes, high blood pressure, high cholesterol and heart disease often take medication that includes nitrates.
Australians can only access medicine with Taladafil through a prescription, while advertising or supplying HERO capsules is illegal, as it has not been entered into the Australian Register of Therapeutic Goods.
Anybody who has any HERO Instant Energy for Males capsules is warned to not use them, but to take them to a pharmacy for safe disposal.
Anybody with health concerns is urged to contact their GP.
"The TGA advises consumers that if they are considering buying therapeutic products online it is important to be careful, especially when the seller does not ask for a valid prescription," the administration said in a release.
Erectile dysfunction is able to be treated through legitimate medical channels, and people who wish to do so should speak to their doctor.
The TGA is working with the Australian Border Force to seize and destroy any future shipments of HERO capsules into the country.