Hobby shop worker Lee Spievak, 69, says that his severed fingertip grew back in four weeks after applying a powder supplied by Dr. Stephen Badylak, an expert in regenerative medicine.

Badylak says the powder causes cells to regenerate and that it brings doctors a step closer to creating and replacing complex organs or even entire limbs, such as arms and legs. Currently, scientists can grow simple tissues like skin, cartilage, bladders, ears, noses, blood vessels and other body parts, according to Discovery News.

Professor Stephen Kaye, a surgeon at Leeds University, points out in Britain’s Daily Mail that Spievak’s finger did not suffer any bone, nerve or tendon loss and simply had to repair skin. “The pictures I’ve seen on the Web show a wound I would have expected to heal and regenerate in any case,” Kaye said.

Whatever is responsible for Spievak’s regrown fingertip, researchers continue to forge ahead in studying limb regeneration. The Pentagon has embarked on a new five-year, $250 million regenerative medicine project aimed at healing soldiers and civilians.

In a recent article, Scientific American magazine outlines studies of salamanders, considered the “gold standard” for limb regeneration in the animal world, and offers a positive assessment of the field’s future.

“Indeed, when we consider all that we have learned about wound healing and regeneration from studies in various animal models, the surprising conclusion is that we may be only a decade or two away from a day when we can regenerate human body parts,” concludes the magazine.