After watching "I was a Teenage Werewolf" I had a spark of curiosity on how werewolves age. I'm sure its a common question many others have had, and so I will explain my findings to the best of my ability and try to answer this question with regards to science.
Age. Its where it all begins. Without a clear definition of what age is, it's tricky to discuss a fictional creatures ability to undergo the process of aging. However, age is more than just a definition. First, you must understand what happens to ours bodies when we age. As humans grow older, several of our biological processes begin to diverge out of our healthy range. The most common one when discussion old age death is your genes. Every cell in the body has a set of genes that tell the cell how to function properly. Picture it like the line of words "Make brown hair". This line will tell the body part that makes hair, to make brown hair. However in order for the line "Make brown hair" to get to where it has to go, it must add on a protective barrier. So "Make brown hair" turns into "AAAA Make brown hair AAAA". As the body tells the hair to make brown hair over and over again, the line starts to lose some of the protective barrier, or A's in this case. As humans near the end of their life the line might instead read "ke brown ha", which to the body doesn't mean anything just like it doesn't mean anything to us.
Werewolves Age Edit
For this post consider werewolves to be created from a bite, or serum in the case of "I was a Teenage Werewolf". According to this author, one of the three ways to be a vampire is to be bitten by one. However, the author does discuss the possibilities of being born a werewolf, but in "Werewolf's Daughter" the werewolf has nine daughters and none of them are werewolves. So if it were true that a werewolf was created from a bite, then it would be possible for Dr. Brandon, in the film to accurately replicate the bacteria, or virus that lives inside of a werewolf, and then create another werewolf in the form of a serum. If this occurs, then the injection has to cause a change in the expression of the genome. Since the only thing in werewolves that is changing when they switch from being human, to being a wolf, is how the genes are expressed, and not changing the actual genetic information, then the way in which werewolves age could have two possibilities, both equally plausible. The first, is that the aging mechanism remains the same. Meaning that werewolves age the exact same way as humans do. However, the alternative theory is that werewolves don't age as long as they continue to change back and forth from werewolf to human. This could be true if when changing from human to werewolf the protective barrier for the genes doesn't degrade, because it only changes once, thus only replicates the genes once, making the protective barrier degrade so slow compared to a regular human that it seems to not degrade at all.