It's often an unexpected moment. One morning we roll out of bed to get ready for work, look in the mirror and see a wrinkle that we never noticed before. When we're young, our skin has an abundance of collagen, elastin and glycosamingoglycans. Collagen provides skin its firmness, elastin makes it elastic and gylcosamingoglycans ensures skin stays hydrated. Our skin also has stem cells which help it heal and regenerate. When we age, you may have guessed, we have less of these components.

The above is called extrinsic aging, which is different than intrinsic aging. The latter happens because of environmental effects such as pollution or tobacco use, although, both types of aging often happen at the same time.

"When you're young, the average turnover for your skin is about 25 to 30 days," said Hal Simeroth, Ph.D., chief technical officer and founder of Stemology. "When we get older, the production slows down, [and] the turnover can take up to 60 days."

To treat aging, people use anti-aging products. This much is obvious. But what isn't so obvious is the type of elements contained inside of these products. More often than not, you'll notice the word "stem cells" printed on the packages' labeling.

Many anti-aging products contain stem cells or, at least, remnants of stem cells such as proteins and amino acids from those cells. These elements encourage our own cells to produce more collagen and elastin and motivate their rejuvenation process. They basically help our skin turn back the clock.

Because stem cells usage is controversial, Jessica Weiser, M.D., a board-certified dermatologist, Women's Health that human stem cells aren't really used in anti-aging products.

"Primarily botanical stem cells are used in these products in order to avoid the controversies of source and method of extraction associated with animal- and human-derived stem cells," Weiser explained. "Grape, raspberry, lilac, rose, and edelweiss are common botanical sources."

While many are skeptical of how effective stem cells are at rejuvenating the skin, most agree anti-aging products contain a number of benefits.

"I believe that these products are worth using primarily for their high concentration of antioxidants, which work to reverse UV-induced skin damage, and also for their potential to improve cell turnover and renewal," said Weiser.

For questions about which anti-aging medicine are best suited for you, it's best to talk to a board-certified dermatologist.