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 Human growth hormone helps maintain the immune system and builds youthful muscle power and strength. Growth hormone levels decline progressively with advancing age. Scientists have demonstrated that restoring youthful levels of growth hormone via regular injections can rejuvenate aging men and women. A provocative study at North Dakota State showed significantly greater survival than controls among elderly mice receiving growth hormone injections. This study was not carried through to completion because the researchers ran out of growth hormone. To help assess the antiaging potential of growth hormone, the Life Extension Foundation, as part of its Rejuvenation Project, will soon be funding a lifespan study of the effects of growth hormone on aging mice at the University of California at Riverside. Another method of boosting growth hormone levels is to take growth-hormone-stimulating nutrients such as arginine and ornithine. Several pharmaceutical companies are developing oral secretogogues, which stimulates growth hormone release.
 DHEA (Dehydroepiandrosterone) is an adrenal hormone that is the precursor for steroid hormones such as testosterone and estrogen. DHEA declines precipitously with advancing age in both men and women. There have been many studies showing that oral DHEA can improve neurological function, immune function, stress disorders, and that it can be protective against some types of cancer and cardiovascular disease. In one clinical study at the
University of California at San Diego, 50 mgs a day of DHEA taken daily over a 6-month period increased lean body mass and muscle strength and the perceived physical and psychological well-being of both men and women. One lifespan study with DHEA has been conducted in mice at a major university. Verbal reports indicate that DHEA was not successful in extending lifespan, but the results of that study have not yet been reported.
 Melatonin is a hormone produced by the pineal gland, which is located beneath the brain. Melatonin is a highly potent antioxidant, which has been described as the pacemaker of the aging clock in humans. It is released every night as part of our time-dependent biorhythms to help induce sleep and recuperation from fatigue. Melatonin has been shown to have anticancer effects. In animal studies in Italy, melatonin and transplants of pineal gland tissue from young animals extended the lifespan of old animals, however the mice used in these studies had suboptimal lifespans. The Life Extension Foundation is funding a study to further assess the effects of melatonin on aging and lifespan in mice.
 Coenzyme Q10 (CoQ10) is a cardioprotective, energy stimulating compound that has been shown to be effective as a means of preventing and treating certain forms of cardiovascular disease and cancer. In a study by Bliznakov, the lifespan of mice was increased by 50% by injections of coQ10. In another study at UCLA Medical Center, the mean but not maximum lifespan of mice was increased by very high oral doses of coQ10. In both studies, mice receiving coQ10 looked especially good and healthy at advanced ages. coQ10 is being assessed further for its effects on aging and lifespan in mice as part of The Lifespan Project.
 NADH is a form of nicotinamide adenine dinucleotide, a coenzyme that assists enzymes involved in energy production within mitochondria, the power plants of the cell. NADH plays an important role in the generation of ATP (adenosine triphosphate), the body's energy currency, and has been found to be effective in Europe in treating Parkinson's and Alzheimer's disease. NADH is also needed for the regeneration of glutathione after it has become oxidized. The Life Extension Foundation has funded a study to examine the effects of NADH on aging and lifespan in mice.
 Lycopene is a member (along with beta-carotene) of a family of plant pigments called carotenoids. There are more than 600 different carotenoids, but lycopene and the carotenes are the most important ones. They are the pigments that give leaves, tomatoes and other plants their bright colors. Lycopene is the best antiaging candidate of this class of compounds because it is the most efficient quencher of an especially dangerous free radical called singlet oxygen. Equally important is the fact that lycopene is regenerated after quenching singlet oxygen, and can then detoxify dangerous molecules without being destroyed. Lycopene levels drop off with age, even if we continue eating the fruits and vegetables that contain it. Lycopene has been shown to increase the survival of irradiated mice, and to decrease the incidence of various types of cancer in mice. It is now the subject of study in The Foundation's Lifespan Project.
 Vitamin E is the major fat-soluble compound that protects our cell membranes against oxidative damage. It can break the self-perpetuating chain of oxidative reactions in unsaturated fatty acids in membranes. Vitamin E also helps maintain the antioxidant activity of selenium, and works with this trace mineral to help boost immune function. There have been highly persuasive studies in humans showing that regular vitamin E intake can reduce the risk of heart attacks in both men and women, and that it can protect us from several types of cancer. In one study, the combination of vitamin E and vitamin C reduced death from all causes. Vitamin E is being studied for its effects on aging and lifespan as part of The Lifespan Project.
 In 1958, biochemists Roger J. Williams and Richard Pelton fed large amounts of vitamin B5 to male and female mice. They found that the treated mice lived an average of 19% longer than controls. A previous study had found that B5 increased the lifespan of fruit flies. The major biochemical role of vitamin B5 appears to be as a constituent of coenzyme A, which is involved in many chemical reactions essential to life, including the detoxification of many dangerous substances. When high doses of vitamin B5 were given to rats they were able to survive in cold water twice as long as controls. Similar results have been found in humans.
 In an experiment conducted at NASA's Ames Research Center in a long-lived strain of mice already in middle-age (18 months of age), the scientists found an 11% increase in lifespan in animals fed vitamin B6 compared to controls. Vitamin B6 plays an important role in many life processes. It is needed for the metabolism of amino acids such as tyrosine and phenylalanine, and is an essential cofactor (along with vitamin B6 and folic acid) in the body's defense against elevated homocysteine levels, which have been linked to arteriosclerosis, heart disease and stroke.
 The "female" steroid hormones estrogen and progesterone play important roles in maintaining bone density and strength, sexual function, mental function and, in women, in countering the effects of the menopause. Recent studies indicate that estrogen may be an effective treatment for age-associated memory problems.* Both estrogen and progesterone are available in a variety of forms -- natural or synthetic, oral or topical. There is considerable interest in the use of plant-derived phytoestrogens, which have weak (but safe) estrogenic activity as a possible replacement for drug forms of estrogen. One product, Natural Estrogen, has been specially designed for this purpose.
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