At a dinner party recently, an attractive young woman shouted from the other end of the table, “Hey, Dr. Greg! What eye cream do you use?” This seemed to be an odd acknowledgment that my eyes didn’t look as old as my age would have her imagine. Should I have been flattered or insulted? Since I was a little of both, I decided to tell her both a truth and a lie. I shouted back, “Nothing!”

It’s true. I don’t use any creams or potions outside of basic moisturizer. I have never had Botox, Restylane, Paralox or any other injectable razzmatazz.

The only surgical knife that has ever touched my face was to remove a skin cancer thingy.

So what’s my “secret”? Exercise.

I can almost hear your groan of disappointment. It’s not something as simple as a lotion you could apply or a pill you could take—something easy to hold back the ravages of time and Sunday Fundays. And though every beauty ad would have you believe the answer to looking good is in a bottle, I am telling you that exercise is as close to a miracle drug as anything you will find.

I really have no idea whether exercise does anything for the skin around your eyes—which, with time, can begin to resemble a scrotum in cold weather. But I am telling you here and now that exercise is what people who look “good for their age” are really doing to look better. Don’t be fooled.

Now, allow me to let you in on a bigger secret—exercise doesn’t just make you look good, it can make you feel good. No, not that ‘endorphins’ twaddle that we’re all so sick of hearing people yammer about after a long run. I am talking a genuine long-term change in mood.

An October 2013 review of 26 years worth of literature in the American Journal of Preventative Medicine found that exercise not only treats depression, but it can also actually prevent it in the long term. Just 20-30 minutes of daily walking or gardening can ward off depression in people of all ages.

What about people with fairly severe depression? A walk may not cure what ails, yet it could help reduce the amount of pills one has to take. According to a four-year study by UT Southwestern Department of Psychiatry, exercise is as effective as giving someone a second antidepressant medication.

To get the best results, you may want to pick up the pace a bit. According to a report in the May 2013 edition of Journal of Psychiatric Practice, three to five sessions a week of 45-60 minutes of moderately intense aerobic exercise or resistance training (that’s treadmill and weights to you and me) is an effective treatment for major depression when combined with medication and psychotherapy.

Decreasing depression isn’t the only benefit. Exercise also alleviates anxiety and staves off stress. According to a 2012 study by the University of Georgia, published in the journal Psychotherapy and Psychosomatics, exercise provided improvements in anxiety symptoms such as irritability, tension, low energy and poor sleep.

As with depression, these changes last. A research team at Princeton reported in the July edition of the journal Neuroscience that physical activity reorganizes the brain so that its response to stress is reduced and anxiety is less likely. Can it get any better than this? Apparently, yes.

Exercise even does some cool stuff like decrease cravings for nicotine in people trying to stop smoking, lowers triglycerides in your blood, has a protective effect against Alzheimer’s and Parkinson’s and prevents brain degeneration in HIV-positive men. It also improves memory as well as or better than crossword puzzles and Sudoku according to a 2012 study by the University of Edinburgh in Scotland in the journal Neurology.

For those who already exercise, pat yourself on the back and keep up the good work! For the newbies, here are some tips.

1. START SLOWLY. Don’t exercise for 60 minutes a day when you have been doing zero minutes a day. Start with five minutes and keep adding.

2. QUASH QUICK FIXES. A friend of mine got liposuction to show off his abs. I took the same amount of money and put it into training sessions. At first he looked better, but guess who has better abs today?

3. GET A TRAINER. Exercise is a science. Learn from an expert. Good trainers will motivate you, teach you proper form and help you with lifestyle changes so that you change for the long haul.

4. REWARD YOURSELF. The best rewards are done just after a workout. A delicious protein shake, a favorite TV show or, my favorite, simply telling yourself “good job.”

5. GET A BUDDY. Working out with a friend will not only get you there but will keep you there when the going gets tough.

Oh yeah, screw “no pain, no gain.” Not surprisingly, when exercise is too difficult, people don’t enjoy it as much and are less likely to do it another day. That doesn’t mean you should make it super easy, either. According to a 2012 study published in Medicine & Science in Sports & Exercise, when exercise is “somewhat hard” people enjoy it more and are thus more likely to repeat it. That’s when the benefit comes—when you repeat it, over and over again.

From a psychological point of view, exercise may be the best thing you can do for yourself outside of eating and sleeping. But I know the real reason you do it—to look better. And, what’s the crime in that? If you exercise to look better, then you will also get to feel better, remember more, learn more efficiently and have a better functioning brain. And just think of the money you’ll save on eye cream!