a multivitamin is you usually the simplest and easiest to take; it also gives you all the nutrients you need.
I have included a link that points out some of the vitamins and nutrients that men should be concerned about.
the main difference is that men's vitamins generally contain little to no iron, whereas women's do.
That is not recommended.
Unless you have a specific condition, a good multivitamin is all you need, in addition to a healthy diet, exercise and plenty of sleep.
There are many kinds of vitamins and I don't what you are preferring. I think the best place to buy is at the drugstores or hospitals. Because they have authorized vitamins there.
There is almost no evidence supporting the benefits of vitamins, so the best vitamins for a man in his thirties are a healthy diet and moderate exercise, same as everybody else.
The best women's mufti-vitamins are those that are derived from whole foods. They contain the co-factors that vitamins need to work right in the body and are complete vitamins. A couple of brands are New Chapter and Phytovitamins, though there are a few other companies that produce them.
Enzymes, vitamins, minerals, and fibers.
YES
No. If you look on the drug facts label it says a certain portion for children 4 and younger and a portion for children 4 and up and adults. But then again it would probably be best if adults take vitamins for men or women.
Prenatal vitamins. My hair (and nails) grew out of control when I was on them!
Information about vitamins for men can be found online at Discovery Health as well as WebMD. A naturopath would be able to provide better recommendations for each individual.