Scientists have tried to bolster the impact of pyrethroids by mixing them with neonicotinoids.
These systemic poisons are the most widely used group of insecticides, especially in agriculture.
They have become controversial in recent years because many scientists believe they are having a detrimental impact on bees and other wildlife.
In this study, the researchers collected populations of bed bugs in Cincinnati and Michigan back in 2012 and exposed them to four different neonicotinoid insecticides.
They then compared these bugs to two other laboratory colonies - one kept for 30 years without exposure to insecticides, the other a pyrethroid-resistant group, collected in New Jersey in 2008.
It took just 0.3 nanograms of neonics to kill more than half of the 30 year colony - but it took around 10,000 nanograms to kill the same percentage of the recently collected insects.
Even though the New Jersey bugs were also collected before the introduction of neonics, they still showed moderate resistance to these chemicals, leading the scientists to believe that these insects can produce large quantities of an enzyme which helps to break down toxic substances.