At least 100 of the 599 documented cigarette additives have “pharmacological” actions, many of which enhance or maintain the delivery of nicotine and may increase the addictiveness of cigarettes, says a new UCLA study in the American Journal of Public Health.

The study found that the additives camouflage odor, visibility, and irritation while enhancing nicotine delivery and masking the symptoms of serious illness associated with smoking.

The study’s findings point to a need for regulation of cigarette additives as lawmakers debate whether to allow federal regulation of tobacco products.

Researchers investigated tobacco industry documents and other sources for evidence of possible pharmacological and chemical effects of tobacco additives.