As of September 2021, the maximum nicotine concentration allowed in vape juice or e-liquid in Canada is 20 mg/mL. This restriction is set by the federal government under the Tobacco and Vaping Products Act (TVPA) to help reduce the risk of addiction and other health issues related to nicotine.
It's important to note that each province and territory may have its own regulations related to vaping, and some may have further restrictions on nicotine concentration levels. It's also important to use vaping products responsibly and only purchase from licensed retailers.