When it comes to certain cancer-causing chemicals in tobacco, e-cigarettes may be a healthier option than regular cigarettes, new research says. But this latest study still can’t settle the ongoing controversy surrounding electronic cigarettes — which are alternately billed as a safer alternative to smoking or a dangerous gateway to even riskier tobacco use

By analyzing the urine of people who smoke cigarettes and people who vape, scientists found that those who vape have lower levels of carcinogens — at least in their pee, according to a study published today in the Annals of Internal Medicine. The study was relatively small, and didn’t investigate actual health outcomes, like lung cancer, in either population. It does, however, hint that certain risks of smoking may be lessened by switching to an e-cigarette.

A team of researchers in the UK collected pee, spit, and questionnaires from 181 smokers and former smokers divided into five groups: former smokers who switched to vaping or another nicotine source like gum or patches at least six months earlier, current smokers who only smoke cigarettes, and current smokers who also use e-cigs or another replacement source of nicotine. People who just inhale the e-cig liquid, with no nicotine, weren’t included.

Levels of nicotine and nicotine byproducts in the pee were roughly the same for all the groups. That probably means that people were still getting the same dose of the drug from the various sources. What differed were the levels of cancer-causing chemicals: people who vaped or who chewed gum or used patches peed out much lower levels of certain carcinogens. That means that using e-cigarettes might help smokers reduce their risk for diseases like lung and oral cancers, heart disease, and lung disease.

These findings don’t mean that e-cigarettes are completely safe, though — especially compared to not smoking at all. For one thing, nicotine is very addictive, and has negative effects on heart health in any form. And while this study looked at whether e-cigarettes expose people to some of the same carcinogens that cigarettes do, the researchers didn’t look at all possible carcinogens. They skipped formaldehyde, for example, which has been found in both cigarette smoke and e-cig vapor.

Like most e-cigarette studies, this one has limitations. It didn’t examine whether cigarette smokers and e-cigarette users were more likely to get certain kinds of disease, like lung cancer. The study participants were also predominantly young, healthy, white men — and they aren’t the only people who vape. So it’s still not clear how differences in genetics, hormones, age, or health status might affect e-cigarette users’ cancer risks.

Until scientists conduct a large-scale, long-term study comparing the actual health outcomes of smokers, vapers, and people who don’t inhale anything, we still won’t know the actual risks — or benefits — of vaping.