The concept of a risk continuum for tobacco and nicotine products has been proposed that represents the likely association of different categories of product with toxicant exposure and possibly risk. At one end are cigarettes, deemed the most risky, and at the other is medicinal nicotine, deemed the lowest risk. This paper focuses on the results from a series of chemical, toxicological and clinical studies on prototype cigarettes designed to substantially reduce exposure to some toxicants. We conclude that there is insufficient evidence to support reduced toxicant cigarettes as a distinct category in the risk continuum, and suggests that it is difficult to determine the potential public health benefit of regulation that sets toxicant limits. The greater toxicant reductions that may be achieved in products that heat rather than burn tobacco or in electronic cigarettes might be necessary to clearly reduce risks compared with cigarettes.