Testosterone Boosters compared - ALRI Jungle Warfare, Bad Ass Mass, Pro Anabol, Restore, Universal Animal Stak and Test, Applied Nutriceuticals Drive, HGH-Up, Free Test, BSN Axis-XT, Gaspari Novedex XT and Halodrol, MuscleTech Cryotest, John Scott Nitro Tribulus and Test-2, Myogenix Alpha Test and Hardcore Test, Nutrix Vitrix T-Up, Universal Tribulus NT-1 and Natural Sterol Complex, Muscleology RedTest red test, BPI M-80, Arimedex HD, MHP T-Bomb-2, Labrada HumanoGrowth,

from Mike Mahler - andropause is considered normal for men in their fifties. The essential factor in optimizing hormones is your ability to handle stress. the stress hormone, cortisol, must be within reasonable range to optimize your hormones and thus feel great. Too much cortisol cannibalizes the sex hormones, such as pregnenelone, and in turn DHEA, androstendione, and finally, testosterone.

       Another critical component in natural hormone optimization is maintaining insulin levels within ideal ranges. Insulin levels within the optimal range are balanced with the hormone glucagon.  Protein provides the body what it needs to make glucagon, so a simple rule of thumb is to eat protein and carbs at every meal.
        The fatter you are, the more estrogen receptors you'll have, which reduces the cellular access to testosterone.  This is why you can't utilize extra testosterone, no matter how much you are making (or supplementing) if insulin is not properly managed.
        Don't let your cholesterol get below 180. The body stops making hormones then.
       IGF 1 is a wonderful anti aging, muscle-sustaining hormone that gets low with high stress levels.

    from Sean Nalewanyj - Quite simply, testosterone is the most important muscle-building hormone in your body and is one of the limiting factors that determines how much muscle a person can build.      
       First, the brain releases a substance called Luteinizing Hormone, LH basically “tells” the body to start producing testosterone. Once this occurs, the adrenal glands release DHEA into the bloodstream. LH and DHEA then travel together to the testes where testosterone production begins. Testosterone can now be released into the bloodstream.
       Do compound exercises with intensity, train legs hard, increase Essential Fatty Acids, limit soy and alcohol, increase broccoli & cauliflower, lower stress and get more sleep.

    The entry above sums up most of what I have read about boosting testosterone without supplements. Here is some more info:

       Testosterone is a powerful anabolic hormone that stimulates and controls the development of different organs such as muscle, bone, skin, sex organs, and most other masculine, physical features. Male testosterone is produced in the testes by a group of cells known as the Leydig cells. They begin secreting high doses of testosterone during puberty to trigger increased lean muscle mass, sex organ development, bone formation and higher energy levels. Testosterone levels peak during a man's early to mid twenties.
        Luteninizing hormone gradually slows down and diminishes as we age. Tribulus terrestris can naturally boost levels of LH -- the increased LH then leads to more healthy testosterone production once again. Zinc and magnesium also help maintain testosterone levels (ZMA).