American Spirit cigarettes may be more addictive than other cigarettes and many varieties of the brand have “high levels of nicotine,” according to one study on the issue. After analyzing the physical characteristics and chemicals in the smoke and tobacco filler of American Spirit cigarettes and five other cigarette brands, researchers found that American Spirit cigarettes generally have more tobacco filler, and, as a result, produce a higher number of puffs — which may expose the brand’s smokers to more tobacco chemicals per cigarette than smokers of other brands.

Another study measured the exposure of harmful or potentially harmful ingredients in American Spirit smokers and in smokers of four other cigarette brands. The results show American Spirit smokers had a higher exposure to nicotine per cigarette smoked compared with other brands, which suggested a “greater addictive potential.”