By now, youve probably read a horror story or two about vaping. Its in the news every day you cant miss it.

People mostly teens whove frequently used e-cigarettes are ending up in the hospital in a fight for their lives. One boys lungs were so damaged that doctors said they looked like those of a 70-year-old whod smoked his entire life. Another teens e-cigarette exploded in his mouth, shattering his jaw. One 17-year-old unexpectedly died after developing a severe respiratory illness linked to vaping. And overall, there have been more than 25 deaths and 1,299 vaping-related lung injuries, according to the Centers for Disease Control and Prevention .

The small USB-like devices were so well-marketed as a safer alternative to cigarettes that its no wonder people scooped them up in droves. Now, people are hooked and paying a scary price for it.

Medical researchers are hustling to understand exactly what happens to the body when its exposed to e-cigarettes and why people are getting so sick. Our understanding of the exact biology that is happening in the disease is still in its very early phases, said Angela Rogers , a pulmonologist at the Stanford Chest Clinic.

Heres what we know so far about how vaping affects your body and brain:

You feel the buzz.

Lets start with what attracts so many people to vaping in the first place: the buzz. Both nicotine and marijuana-based e-cigarettes can make you feel good, as they release yummy chemicals in your brain (think dopamine and serotonin). This causes people to feel a pleasurable high.

Quick point: if youre vaping something with tetrahydrocannabinol (THC), the psychoactive chemical in marijuana, the high you get will be more intense than the buzz you get from nicotine, naturally.

You crave more.

Vaping isnt really a one-and-done sort of deal. Nicotine alone is extremely addictive its the third-most addictive substance after heroin and cocaine, according to health experts. Put it into an e-cigarette and its even more addictive.

Thats because the newer vaping products are engineered to easily deliver more nicotine to the brain, faster, with less harshness, said Bonnie Halpern-Felsher , a pediatric physician with Stanford University and the founder and director of the Tobacco Prevention Toolkit.

This is especially true for young people, whose brains are still developing and remain very vulnerable to nicotine exposure. Given that brain development continues until the age of about 25, youth are significantly more likely to become addicted to nicotine than are adults, Halpern-Felsher said.

Nicotine is far more addictive than THC, but the same principle applies to weed-based vaping products. The more you use it, the more you may crave it.