Juul nicotine hit may be 'Worst for kids, best for smokers'

She tried gums, patches and various electronic cigarettes to quit smoking. What finally worked for Chantel Williams from Oregon, was a small, reusable e-cigarette called Juul that packs a big nicotine punch.

Williams who smoked for decades said "I look better. I feel better and I don't smell. It is fantastic." That nicotine hit and its easy-to-inhale vapor is one reason why Juul is so popular — and so feared.

Harvard Medical School tobacco treatment specialist Dr. Nancy Rigotti says "That's the trouble with Juul: It's probably the worst for kids but it might be the best for adult smokers."

The brainchild of two Stanford University design students, Juul launched in 2015 and quickly leapfrogged over its competitors to become the top-selling e-cigarette in the U.S. Today, the privately held company controls nearly three-quarters of the $3.7 billion-dollar retail market for e-cigarettes, spawning dozens of copycat brands along the way.

With Juul's rise came an explosion of underage vaping, alarming public health officials and lawmakers. According to a government survey, last year 1 in 5 U.S. high school students reported vaping in the previous month.