“In theory, non-animal tests could be much cheaper and much faster,” said Warren Casey, the director of the U.S. National Toxicology Program’s Interagency Center for the Evaluation of Alternative Toxicological Methods, which analyzes alternatives to animal use for chemical- safety testing.

Another concern is that in some types of research, animals are too different from humans to successfully predict the effects that certain products will have on our bodies. “So we’ve got ethics, efficiency and human relevance,” Casey told Live Science, the three main factors driving the hunt for alternatives.

So, what are the most promising options so far? (read more in LiveScience)