Here's what the Mayo Clinic has to say about some popular anti- aging therapies:

Hormone supplements

Hormones are chemicals made by your body to regulate the activities of vital organs. Because hormone levels decline with age, some scientists speculate that hormones might play a role in the aging process. Proponents of hormone products believe you can set back the body's clock by restoring hormone levels to those of youth. Supplements include:

- Dehydroepiandrosterone - The hormone is converted by the body into the sex hormones estrogen and testosterone. DHEA is most abundant in your body around age 25; after that, production wanes and drops off dramatically by age 65.

Proponents says it slows aging, increases bone and muscle strength, bolsters cognition, burns fat, increases immunity and protects against many chronic diseases.

In 1985, the Food and Drug Administration banned the product. However, it resurfaced in the mid-'90s as an over-the-counter dietary supplement after Congress removed dietary supplements from premarket safety evaluations required of food ingredients and drugs.

Because dietary supplements marketed as anti-aging supplements are not regulated by the FDA, consumers can't be sure of product purity or the amount of active ingredient in a given supplement from one package to the next. Therefore, there's no guarantee anti- aging supplements, such as DHEA, are safe.

With that in mind, DHEA should be taken under the supervision of a doctor, since existing DHEA levels vary and people with higher levels run the risk of overdose. In excess amounts, DHEA causes liver damage, certain cancers, heart disease and unwanted facial hair.

- Human growth hormone - The human growth hormone is said to build muscle, renew energy and burn fat. In younger patients, studies show hGH improves athletic performance and contributes to weight loss. In older recipients, it is said to restore nerve function, renew energy and reverse the aging process.

Because it is a growth hormone, it can stimulate existing cancers, diabetes, high blood pressure and joint pain.

Antioxidants

Antioxidants are vitamins, minerals and enzymes that protect the body by neutralizing free radicals, which are byproducts of the cells' normal metabolism. Free radicals are believed to be associated with age-related changes and certain diseases.

They interact with other molecules in the bloodstream and can prevent them from carrying out their prescribed functions, potentially causing a good cell to mutate or die. As we get older, our bodies produce free radicals at a faster rate

Athough studies of some antioxidants are promising, caution is needed. Since it's not yet clear if taking antioxidant supplements is safe over the long haul, it's better instead to eat more antioxidant- rich foods, such as fresh fruits and vegetables. Some antioxidents are:

- Vitamin E - Vitamin E shows promise for protecting against cardiovascular disease. It also might protect against Alzheimer's and Parkinson's diseases. If you have cardiovascular disease, the benefits of taking no more than 400 international units per day probably outweigh the risks.

- Vitamin A and beta carotene - Several well-designed studies have found that supplements of beta carotene, which is converted to Vitamin A in our bodies, offer no protection against heart disease. Two studies found an increased risk of lung cancer among smokers who took beta carotene supplements.

Those interested in increasing their intake of vitamin A or beta carotene are probably better off eating more red and yellow vegetables than taking supplements.

- Vitamin C - Studies have shown that people who eat diets high in vitamin C, which is found mainly in citrus fruits, have lower rates of cancer and heart disease. However, it is unclear whether taking vitamin C supplements has similar benefits.

- Selenium - This antioxidant mineral is found primarily in seafood and liver and might help prevent cancer. However, excessive amounts might cause hair and nail loss. More research is needed.

- Coenzyme Q10 - The antioxidant is produced by the body, but also has many dietary sources, including meat and seafood.

Claims that it can slow aging and stop the spread of cancer are unproven. However, some evidence suggests that it might hold promise as a treatment for congestive heart failure.

　　From Healthy.net