Zinc
Zinc, which should already be a part of your comprehensive multimineral supplement, is an essential trace mineral that functions in the activity of approximately three hundred different enzymes. In terms of testosterone and muscle maintenance, 60 percent of the body's zinc supply is stored in the muscles, and zinc is involved in numerous metabolic reactions related to testosterone production, wound healing, energy production, muscle growth, cellular repair, and reproductive function (especially male fertility). Even mild zinc deficiency has been associated with reduced testosterone levels, suppressed libido (sex drive), depressed immunity, decreased sperm count, and impaired memory.
Luckily, dietary supplementation with zinc at levels of 15-45 mg per day has been shown to increase testosterone levels back to normal ranges, improve immune function, and restore sex drive. These levels of zinc supplementation should not pose any significant adverse side effects, but zinc supplementation needs to be balanced with copper intake (2 mg of copper for every 15 mg of zinc) to avoid the onset of copper deficiency caused by unbalanced zinc supplementation.
Cordyceps
Cordyceps (Cordyceps sinensis) is a Chinese mushroom that has been used for centuries to reduce fatigue, increase stamina, and improve lung function. Traditionally, it was harvested in the spring at elevations above fourteen thousand feet, restricting its availability to the privileged. You may remember news reports of cordyceps from a few years ago when a group of Chinese athletes began suddenly breaking world records in swimming and running events. Many of the athletes had been supplementing their diets with an extract from the cordyceps mushroom (along with turtle-blood soup and anabolic steroids).
Despite the case of the steroid-laced Chinese athletes, several small-scale studies of cordyceps have shown improvements in lung function, suggesting that athletes may benefit from an increased ability to take up and use oxygen. A handful of studies conducted on Chinese subjects have shown increases in libido (sex drive) and restoration of testosterone levels (from low to normal) following cordyceps supplementation. Remember that during stressful events cortisol levels rise while testosterone levels drop. Using cordyceps as a way to normalize these suppressed testosterone levels can help to modulate the cortisol-to-testosterone ratio within a lower (and healthier) range. Many of the claims for cordyceps parallel those of ginseng, because cordyceps is also reported to increase energy levels, sex drive, and endurance performance.
Dietary supplements of cordyceps at levels of 2-4 grams per day are not associated with any significant side effects, although the possibility for a slight blood-thinning effect could reduce blood clotting somewhat. Cordyceps supplements are available primarily in powder and capsule forms at mainstream supplement stores, and the dried mushroom can occasionally be found in herbal pharmacies and from practitioners of traditional Chinese medicine (but it is very expensive in this form).
CLA
Conjugated linoleic acid (CLA) is found primarily in meat and dairy products, but the form of CLA used most commonly in dietary supplements is manufactured from vegetable oils such as sunflower oil. CLA is thought to increase the production of prostaglandins, which are derived from fatty-acid molecules and have been linked to an elevated synthesis of growth hormone and various anticatabolic effects (prevention of muscle breakdown) during periods of high stress. In athletes, increased growth-hormone levels are viewed as beneficial for promoting enhanced muscle growth and strength-but CLA does not appear to enhance muscle growth as effectively as it may be able to suppress muscle loss (at least in humans). CLA, via its involvement in prostaglandin metabolism, may also be able to increase blood circulation to the muscles and adipose tissue, an effect that has been suggested to improve muscle function and fat mobilization.
The majority of research on the dietary intake of CLA has been conducted in animals, but newer studies in humans are quite positive. Across the range of studies in rodents and in humans, CLA supplementation has been shown to reduce appetite, lower body weight, and enhance muscle maintenance, especially during active weight loss (viewed by the body as a powerful stressor).
Typical dosage recommendations are 3-6 grams per day. Most people ingest less than 1 gram per day from meat and dairy foods. Because CLA is an oil (liquid), supplements are provided almost exclusively in the form of softgel capsules; taking several large capsules per day is necessary to get an effective dose.
HMB
HMB (hydroxymethylbutyrate) is a metabolite of the amino acid leucine (one of the branched-chain amino acids discussed earlier) that plays a role in regulating protein metabolism. In fact, HMB is thought to be the active form of leucine. HMB is found in the diet in small amounts in some protein-rich foods such as fish and milk. Depending on total protein and leucine intake, HMB production in the body may average about 1/4-1 gram per day.
There is some evidence that HMB reduces muscle catabolism and may protect against muscle damage. NASA has evaluated HMB as a dietary approach to preventing the muscle wasting associated with prolonged space flight (talk about a stressful situation!). Exercise studies have shown that 1.5-3 grams of HMB daily during weight training can reduce muscle loss and muscle damage. No side effects have been reported in studies of HMB supplementation, but HMB can be quite expensive to take at these levels, making it less attractive to many people as a general muscle-maintenance supplement. Like DHEA, commercial sources of HMB are typically encapsulated powders marketed to bodybuilders and fitness enthusiasts, but HMB is also frequently added to protein powders and related muscle-building products.
by Shawn M Talbott, PhD