NatioNal iNstitute oN agiNg

NatioNal iNstitutes of health

Department of health and human services

Can We Prevent Aging?

Tips from the National Institute on Aging

People are living longer. In 1970, the average 

life expectancy at birth was 70.8 years; in 2000, 

it was 76.9 years; and by 2030 is it estimated that 

the “oldest-old,” age 85 and older, could grow to 

10 million people. 

Views on aging are also changing. It no longer 

necessarily means physical decline and illness—

in the last two decades, the rate of disability 

among older people has declined dramatically. 

The National Institute on Aging (NIA), part 

of the Federal Government’s National Institutes 

of Health (NIH), investigates ways to support 

healthy aging and prevent or delay the onset 

of diseases that disproportionately affect us as we 

age. These studies not only may increase what is 

known as “active life expectancy”—the time of 

advancing years free of disability—but also may 

promote longevity. NIA’s research includes 

hormone and dietary approaches, including 

calorie restriction. 

Results from NIA-sponsored studies and others 

are likely to improve our understanding of the 

benefits and risks of hormone supplements, 

calorie restriction, and other interventions to 

promote healthy aging. This tip sheet provides 

an overview of what we know about hormone 

supplements and calorie restriction and the 

research needed to learn more. Until we have 

a better understanding, it is a good idea to be 

skeptical of claims that hormone or other supplements can solve your age-related problems. 

Instead, focus on what is known to help promote 

healthy aging: healthy eating and physical 

activity. 

What Is a Hormone?

The word “hormone” comes from the Greek 

word, hormo, meaning to set in motion. 

Hormones are chemical messengers that 

set in motion different processes to keep our 

bodies working properly. For example, they are 

involved in our metabolism, immune function, 

sexual reproduction, and growth. Hormones are 

made by specialized groups of cells within the 

body’s glands. The glands—such as the pituitary, 

thyroid, adrenals, ovaries, and testes—release 

hormones into the body as needed to stimulate, 

regulate, and control the function of other 

various tissues and organs involved in biological 

processes.

We cannot survive without hormones. As 

children, hormones help us “grow up.” In teenagers, they drive puberty. As we get older, some 

of our hormone levels naturally decline. But 

what does that mean? Scientists do not know 

exactly. In order to know more, NIA investigates 

how replenishing hormones in older people 

affects frailty and function. Many of these 

studies focus on hormones that decline with 

age, including:

Q Growth hormone 

Q Melatonin 

Q Dehydroepiandrosterone (DHEA)

Q Testosterone 

Q Estrogen and progesterone (as part 

of menopausal hormone therapy)
can we prevent aging?

2

How Hormones Work 

Most hormones are typically found in very 

low concentrations in the bloodstream. But 

a hormone’s concentration will fluctuate 

depending on the body’s activity. Like a key that 

unlocks a door, a hormone molecule is released 

by a gland and travels through the blood until it 

finds a cell with the right fit, a “receptor.” The 

hormone latches onto a cell’s receptor and a 

signal is sent into the cell. These signals may 

instruct the cell to multiply, make proteins or 

enzymes, or perform other vital tasks. Some 

hormones can even cause a cell to release other 

hormones. 

One hormone may fit with many types of cells 

but may not affect all cells in the same way. For 

example, one hormone may stimulate one cell to 

perform a task but it might also turn off a different cell. Additionally, how a cell responds to a 

hormone may change throughout life. 

Hormone Supplements

Levels of some hormones change naturally over 

the lifespan. Some hormones increase with age, 

like parathyroid hormone that helps regulate the 

amount of calcium in the blood and bone. Some 

tend to decrease over time, such as testosterone 

in men and estrogen in women. When the body 

fails to make enough of a hormone because of a 

disease or disorder, a doctor may prescribe 

hormone supplements. As opposed to hormones 

produced naturally by the body, hormone 

supplements come in many forms such as pills, 

shots, topical (rub-on) gels, and medicated skin 

patches. 

You may have read magazine articles or seen 

television segments suggesting that hormone 

supplements can make people feel young again 

or can slow or prevent aging. That’s because 

finding a “fountain of youth” is an attractive 

story that captivates us all. The truth is no 

research to date has shown that hormone supplements add years to life or prevent age-related 

frailty. And, while some supplements have real 

health benefits for people with clinical hormone 

deficiencies due to a disease or disorder, they 

also can cause harmful side effects. That’s why 

people who have a diagnosed hormone deficiency should still only take hormone supplements 

under a doctor’s supervision. 

In some cases, the U.S. Food and Drug Administration (FDA) may have approved a hormone 

supplement for one purpose, but it is prescribed 

by physicians for another. This “off-label” use 

may occur when physicians believe that research, 

such as clinical studies done on other groups of 

people, demonstrates a supplement’s usefulness 

for another condition. While this is the normal 

process for evaluating drugs already approved by 

the FDA, consumers should be aware that a 

particular off-label use of a drug may not have 

been tested and verified to the same degree as the 

original use of the drug.

Dangers of Hormone 

Supplements 

Higher concentrations of hormones in your 

body are not necessarily better. The body maintains a delicate balance between how much 

hormone it produces and how much it needs to 

function properly. Natural hormone production 

fluctuates throughout the day. That means that 

the amount of hormone in your blood when you 

wake up may be different 2, 12, or 20 hours later. 

If you take hormone supplements, especially 

without medical supervision, you can adversely 

affect this tightly controlled, regulated system. 

Hormone supplements cannot replicate your 

body’s natural variation. Because hormonal 

balance is so intricate, too much of a hormone in 

your system may actually cause the opposite of 

your intended effect. For example, taking a 

hormone supplement can cause your own 

hormone regulation to stop working. Or, your 

body may process the supplements differently 

than the naturally produced hormone, causing 

an alternate, undesired effect. It is also possible 

that a supplement could amplify negative side 

effects of the hormone naturally produced 

by the body. Scientists may not know the 

consequences. 
3

Some hormone-like products are sold over-thecounter without a prescription. Self-medicating 

with them can be dangerous. Products that are 

marketed as dietary supplements are not regulated by the FDA. This means that companies 

making dietary supplements do not need to get 

FDA approval or provide any proof that their 

products are safe and effective before selling 

them. There is no guarantee that the “recommended” dosage is safe, that there is the same 

amount of active ingredients in every bottle, or 

that the substance is what the company claims. 

Because there are no standards, the hormonelike dietary supplements sold over-the-counter 

may not have been thoroughly studied and 

potential negative side effects may not be 

understood or defined. In addition, these overthe-counter products may interfere with your 

other medications. NIA does not recommend 

taking any supplement touted as an “anti-aging” 

remedy because there is no proof of effectiveness 

and the health risks of short and long-term use 

are unknown. 

Human Growth Hormone

Human growth hormone (hGH) is important for 

normal growth and development, as well as for 

maintaining tissues and organs. It is made by the 

pituitary gland, a pea-sized structure located at 

the base of the brain. 

Research supports supplemental use of hGH 

injections in certain circumstances. For 

instance, hGH injections can improve the 

growth of children who do not produce enough 

hGH. Sometimes hGH injections may be prescribed for young adults whose obesity is the 

result of having had their pituitary gland surgically removed. These uses are different from 

taking hGH as an anti-aging strategy. As with 

other hormones, hGH levels often decline with 

age, but this decrease is not necessarily bad. At 

least one epidemiological study suggests that 

people who have high levels of hGH are more 

apt to die at younger ages than those with lower 

levels of the hormone. Researchers have also 

studied animals with genetic disorders that 

suppress growth hormone production and 

secretion and found reduced growth hormone 

secretion may actually promote longevity in 

those species that have been tested.

Although there is no conclusive evidence that 

hGH can prevent aging or halt age-related 

physical decline, some clinics market hGH for 

that purpose and some people spend a great deal 

of money on such supplements. Shots can cost 

more than $15,000 a year. These shots are only 

available by prescription and should be administered by a doctor. But, because of the unknown 

risks, it is hard to find a doctor who will prescribe hGH shots. Over-the-counter dietary 

supplements, known as human growth hormone 

releasers, are currently being marketed as lowcost alternatives to hGH shots. But claims of 

their anti-aging effects, like all those regarding 

hGH, are unsubstantiated. 

Research is starting to paint a fuller picture of 

the effects of hGH supplements, but there is still 

much to learn. For instance, study findings 

indicate that supplemental hGH can increase 

muscle mass; however, it seems to have little 

impact on muscle strength or function. 

Questions about potential side effects, such 

as diabetes, joint pain, and fluid build-up leading 

to high blood pressure or heart failure remain 

unanswered, too. A recent report that children 

who were treated with pituitary growth hormone 

have an increased risk of cancer created a heightened concern about the dangers of hGH injections. Whether or not older people treated with 

hGH for extended periods have an increased risk 

of cancer is unknown. To date, only small, 

short-term studies have looked specifically at 

hGH as an anti-aging therapy for older people. 

Before supporting the use of hGH as an antiaging therapy, the potential benefits and risks 

should be assessed through additional research. 

Melatonin

Melatonin is a hormone involved with our daily 

sleep/wake cycle. It is made by the pineal gland 

located in the brain. Despite some claims to the 

contrary, melatonin production and release does 

not necessarily decrease with age. Instead, a 
4

number of factors, including light exposure and 

use of some common medications can affect 

melatonin secretion in people of any age.

As with other hormones, melatonin is marketed 

as a dietary supplement. Consumers should look 

with caution at claims about melatonin supplements’ effects. 

One claim for melatonin supplements is that 

they are an anti-aging remedy, but research on 

the anti-aging effects has been very limited and 

focused on animals, not humans. There are also 

claims that melatonin helps with sleep. Research 

findings have shown that melatonin supplements, in amounts ranging from 0.1 to 0.5 

milligrams, can improve sleep in some cases; 

however, if taken at the wrong time, melatonin 

can actually disrupt the sleep/wake cycle. And, 

melatonin’s benefits as an antioxidant have been 

touted. Antioxidants protect the body from the 

harmful effects of by-products, known as free 

radicals, made when the body changes oxygen 

and food into energy. Early test-tube studies 

suggested that, in large doses, melatonin might 

be an effective antioxidant. More research is 

needed to know if using melatonin supplements 

as an antioxidant will decrease the amount of 

antioxidants cells produce naturally. 

Side effects of melatonin supplements may 

include confusion, drowsiness, and headache. 

Animal studies suggest that melatonin may cause 

some blood vessels to constrict, a condition that 

could be dangerous for people with high blood 

pressure or other cardiovascular problems. 

The usual dose of melatonin sold without a 

prescription in stores is 3 milligrams. This dose 

is much larger than the 0.1 to 0.5 milligrams of 

melatonin researchers used to study its effects on 

sleep. People who take these supplements may 

have a 10- to 40-times higher blood concentration of melatonin than normal. Long-term 

effects of such high concentrations of melatonin 

on the body are still unknown. Use caution when 

considering taking these supplements until 

researchers learn more. 

DHEA

Dehydroepiandrosterone, or DHEA, is made 

from cholesterol by the adrenal glands, which sit 

on top of each kidney. It is converted by the 

body into two other important hormones: 

testosterone and estrogen. 

For most people, DHEA production peaks in the 

mid-20s and then gradually declines with age. 

The effects of this decline including its role in 

the aging process are unclear. Even so, some proponents claim that over-the-counter DHEA 

supplements can improve energy and strength 

and boost immunity. Claims are also made that 

supplements increase muscle and decrease fat. 

To date, there is no conclusive scientific evidence 

that DHEA supplements have any of these 

benefits. 

The conversion of naturally produced DHEA 

into a different amount of estrogen and testosterone is highly individualized. There is no way 

to predict whose body will make more and 

whose will make less of these hormones. Having 

an excess of testosterone and estrogen in your 

body can be risky. 

Scientists do not yet know the effects of longterm use (over 1 year) of DHEA supplements. 

Early indications are that these supplements, 

even when taken briefly, may have several 

detrimental effects on the body, including liver 

damage. But the picture is not clear. Two shortterm studies showed that taking DHEA supplements has no harmful effects on blood, prostate, 

or liver function. However, these studies were 

too small to lead to conclusions about the safety 

or efficacy of DHEA supplementation. 

Researchers are working to find more definite 

answers about DHEA’s effects on aging, muscles, 

and the immune system. In the meantime, if you 

are thinking about taking DHEA supplements, 

be aware that the effects are not fully known and 

might turn out to cause more harm than good. 
5

Testosterone

Most people know testosterone as the hormone 

that transforms a boy into a man and is somehow associated with sex drive. That may be 

why some men are concerned about a possible 

decrease in testosterone production as they age. 

Testosterone is a vital sex hormone that plays an 

important role in puberty. In men, testosterone 

not only regulates sex drive (libido), it also 

helps regulate bone mass, fat distribution, 

muscle mass and strength, and the production 

of red blood cells and sperm. But testosterone 

isn’t exclusively a male hormone—women 

produce small amounts, as well. In men, testosterone is produced in the testes, the reproductive 

glands that also produce sperm. The amount of 

testosterone produced in the testes is regulated 

by the hypothalamus and the pituitary gland.

As men age, their testes often produce somewhat 

less testosterone, especially when compared to 

years of peak testosterone production during 

adolescence and early adulthood. Normal testosterone production ranges widely, and it is 

unclear what amount of decline or how low a 

level of testosterone will cause adverse effects. 

In recent years, the popular press has reported 

frequently about male menopause, a condition 

supposedly caused by diminishing testosterone 

levels in aging men. There is scant scientific 

evidence that this condition, also known as 

andropause or viropause, exists. And the likelihood that an aging man will experience a 

major shutdown of testosterone production 

similar to a woman’s menopause is very remote. 

In fact, many of the changes that take place in 

older men often are incorrectly attributed to 

decreasing testosterone levels. For instance, 

some men experiencing erectile difficulty 

(impotence) may be tempted to blame it on 

lowered testosterone, when in many cases 

erectile problems are due to circulatory 

problems.

In certain cases, such as in men whose bodies 

make very little or no testosterone, testosterone 

supplementation may offer benefits. FDAapproved testosterone supplements come in 

different forms, including patches, injections, 

and topical gels. Men whose testes have been 

damaged or whose pituitary glands have been 

harmed or destroyed by trauma, infections, or 

tumors may be prescribed testosterone. Supplements can also help men with exceptionally low 

testosterone levels maintain strong muscles and 

bones and increase their sex drive. It is unclear if 

men who are at the lower end of the normal 

range for testosterone production would benefit 

from supplementation.

More research is needed to learn what effects 

testosterone replacement may have in healthy 

older men without these extreme deficiencies. 

NIA is investigating the role of testosterone 

therapy in delaying or preventing frailty and 

helping with other age-related health issues. 

Results from preliminary studies involving small 

groups of men have been inconclusive. Specifically, it remains unclear to what degree testosterone supplements can help men maintain strong 

muscles and sturdy bones, sustain robust sexual 

activity, or sharpen memory. 

There are also concerns about the long-term 

harmful effects that supplemental testosterone 

might have on the aging body. Some epidemiologic studies suggest that higher natural levels of 

testosterone are not associated with a higher 

incidence of prostate cancer—the second leading 

cause of cancer death among men. However, 

scientists do not know if taking supplemental 

testosterone increases men’s risk for developing 

prostate cancer or promoting the growth of an 

existing tumor. There is also concern about a 

potential increased risk for stroke based on 

studies that suggest that testosterone supplementation might trigger excessive red blood cell 

production, which thickens the blood. 

The bottom line: Although some older men who 

use testosterone therapy may report feeling more 

energetic or younger, there is no scientific proof 

that testosterone therapy in healthy men will help 

them age better. Until more scientifically rigorous 

studies are conducted, it is not known if the 
6

can we prevent aging?

possible benefits of testosterone therapy outweigh 

any of its potential risks. NIA continues to conduct research to gather more evidence about the 

effects of testosterone supplements in aging men.

Hormones in Women

Estrogen and progesterone are two hormones 

that play an important part in women’s 

menstrual cycle and pregnancy. Estrogen also 

helps maintain bone strength and might prevent 

heart disease and protect memory before menopause. Both estrogen and progesterone are 

produced naturally by the ovaries. However, 

after menopause, the ovaries stop making these 

hormones. For more than 60 years, millions of 

women have used estrogen supplements to 

control for menopausal symptoms, especially hot 

flashes and vaginal dryness. Women also take it 

to prevent or treat osteoporosis—loss of bone 

strength—that often happens after menopause. 

The use of estrogen (by women whose uterus has 

been removed) or estrogen with progesterone or 

a progestin, a synthetic form of progesterone 

(by women with a uterus), to treat the symptoms 

of menopause is called menopausal hormone 

therapy (MHT), formerly known as hormone 

replacement therapy (HRT).

There is a rich research base investigating 

estrogen. Many large, reliable long-term studies 

of estrogen and its effects on the body have been 

conducted. Yet, much remains unknown. In fact, 

the history of estrogen research demonstrates 

why it is important to examine both the benefits 

and risks of a hormone before it becomes widely 

used. Here’s what scientists know: 

Q Endometrial problems—While estrogen 

helps some women with symptom management 

during and after menopause, it can raise the risk 

of certain problems. Estrogen may cause a 

thickening of the lining of the uterus (endometrium) and a slightly increased risk of endometrial cancer. To lessen these risks, doctors now 

prescribe progestin to women with a uterus to 

protect the lining.

Q Heart disease—The role of estrogen in heart 

disease is complex. Early studies suggested MHT 

could lower postmenopausal women’s risk for 

heart disease—the number one killer of women 

in the United States. But results from the Women’s Health Initiative (WHI), a study of MHT by 

the NIH, suggest that using estrogen with or 

without a progestin after menopause does not 

protect women from heart disease and may even 

increase their risk. 

 In 2002, WHI scientists reported that using 

estrogen plus progestin actually elevates some 

postmenopausal women’s chance of developing 

heart disease, stroke, blood clots, and breast 

cancer, but women also experienced fewer hip 

fractures and cases of colorectal cancer. In 2004, 

WHI scientists published another report, this 

time on postmenopausal women who used 

estrogen alone, which had some similar findings: 

women had an increased risk of stroke and blood 

clots, but fewer hip fractures. Then, in 2007, a 

closer analysis of the WHI results indicated that 

younger women, ages 50 to 59 at the start of the 

trial, who used estrogen alone had significantly 

less plaque in their coronary arteries than 

women not using estrogen. Increased plaque in 

coronary arteries is a risk factor for heart attacks. 

Scientists also determined that the risk of heart 

attack might not be increased in women who 

started MHT less than 10 years after menopause, 

but that there is increasing risk in women who 

begin MHT more than 10 years after menopause. 

Q Dementia—Some studies suggest that 

estrogen may protect against Alzheimer’s disease. However, this has not yet been proven. In 

2003, researchers in a sub-study of the WHI, 

called the WHI Memory Study (WHIMS), 

reported that women age 65 and older who take 

a combination of estrogen and progestin were at 

twice the risk for developing dementia than 

women who do not take any hormones. In 2004, 

these WHIMS scientists reported that using 

estrogen alone could also increase the risk of 

developing dementia in women age 65 and older 

compared to women not taking any hormones. 
7

For all the research findings, there are still many 

unknowns about the risks of MHT. For instance, 

scientists have not yet determined if risks differ 

between women who have menopausal symptoms and those who don’t. Also, because women 

in their early 50’s were only a small part of the 

WHI, scientists do not yet know if certain risks 

are applicable to younger women who use 

estrogen to control symptoms during the 

menopausal transition. 

You may also have heard about a relatively new 

approach to hormone therapy for women—

bioidentical hormones. These are man-made 

hormones (from plants such as soy or yams) that 

have the same chemical structure as hormones 

produced by the human body. The term “bioidentical hormones” is now also being applied to 

the practice of compounding or combining 

hormones such as estrogen and progesterone, 

theoretically based on a woman’s individual 

hormonal needs. Large clinical trials of these 

compound hormones have not been done, and 

many bioidentical hormones that are available 

without a prescription are not regulated or 

approved for safety and efficacy by the FDA. 

FDA-regulated bioidentical hormones, such as 

estradiol and progesterone, are available by 

prescription for women considering MHT.

For middle age and older women, the decision to 

take hormones is far more complex and difficult 

than ever before. Questions about menopausal 

hormone therapy remain: Would using a different estrogen and/or progestin or different dose 

change the risks? Would the results be different 

if the hormones were given as a patch or cream, 

rather than a pill? Would taking the progestin 

less often be as effective and safe? Does starting 

menopausal hormone therapy around the time 

of menopause compared to years later change the 

risks? Can we predict which women will benefit 

or be harmed by using menopausal hormone 

therapy? As these and other questions are addressed by research, women should re-review the 

pros and cons of menopausal hormone therapy 

with their doctors, assess the personal risks and 

benefits, and then make an informed decision 

about whether or not this therapy is for them. 

NIA has additional free information on menopausal hormone therapy. Call 1-800-222-2225 

(toll-free) or visit the NIA website at www.nia.

nih.gov/HealthInformation. 

Calorie Restriction, Intermittent 

Fasting, and Resveratrol

Scientists are discovering that what you eat, how 

frequently, and how much may have an effect on 

quality and years of life. Of particular interest 

has been calorie restriction, a diet comprised by 

generally 25 to 40 percent fewer calories than 

normal but including all needed nutrients. 

Research in animals has shown calorie restriction to have an impressive effect on disease and 

markers of aging. It has been found to extend 

the life of protozoa (very small, one-celled 

organisms), yeast, fruit flies, mice, and rats. 

Recent calorie restriction studies with humans 

and other primates, such as monkeys, are ongoing. However, early findings of the Comprehensive Assessment of Long-term Effects of 

Reducing Intake of Energy (CALERIE) study, 

show that adults who cut their calorie consumption by 25 percent lowered their fasting insulin 

levels and core body temperature, both of which 

correlate with increased longevity in animal 

models. In other studies with non-human 

primates, researchers have found that calorie 

restriction reduced incidence of heart disease 

and cancer. 

Scientists do not know if long-term calorie 

restriction is safe for humans. It is unclear 

whether or not a calorie-restricted diet will ever 

be recommended for people. However, studying 

calorie restriction may offer new insights into 

the aging process and biological mechanisms 

that could influence healthy aging. This research 

may also provide clues about how to prevent or 

delay diseases that become more prevalent with 

age. 
can we prevent aging?

Other ongoing studies focus on identifying 

chemicals that mimic calorie restriction’s 

benefits. Resveratrol, found naturally in very 

small amounts in grapes and nuts, is one of the 

compounds being studied. Scientists compared 

two groups of overweight mice on a high fat diet. 

One group was given a high dose of resveratrol. 

The overweight mice receiving resveratrol were 

healthier and lived longer than the other overweight group. In a follow-up study, scientists 

found that, when started at middle age, resveratrol slowed age-related health problems in mice 

on a standard diet but did not increase longevity. 

More research is needed before scientists know 

if resveratrol is safe for people or even if it has 

the same effects as it has in mice. 

Scientists are also studying the effect of intermittent fasting or reduced meal frequency. In 

animal models, like mice, reduced meal frequency appears to have a protective effect on the 

brain and may also help with heart function and 

regulating sugar in the blood. However, the 

influence of intermittent fasting on human 

health and longevity is currently unclear. 

While research into calorie restriction and 

intermittent fasting continues, there is already 

plenty of research supporting the value of a 

healthy, balanced diet and physical activity to 

help delay or prevent age-related health 

problems. 

Many Questions, Seeking 

Answers

NIA supports research that seeks to tell us 

more about aging and the risks and benefits of 

potential interventions such as hormone therapies, supplements, and calorie restriction. One 

goal is to determine whether DHEA, melatonin, 

and other hormonal supplements improve the 

health of older people, have no effect, or are 

harmful. Researchers are also trying to determine if calorie restriction is safe for humans and 

if there are any compounds that could replicate 

in humans the benefits of calorie restriction seen 

in animals. 

These studies will take some time. Research on 

supplements and calorie restriction is ongoing 

and a great deal of basic animal and clinical 

research is yet to be done. Don’t be surprised 

if these studies open the door to more questions 

as well as answers. Research is an incremental 

process; results can move knowledge forward, 

but can also take you back to basics. 

Until more is known about DHEA, melatonin, 

hGH, and resveratrol, consumers should view 

these types of supplements with a good deal of 

caution and doubt. Despite what advertisements 

and media, like television and magazines, may 

claim, there are no specific therapies proven to 

“prevent” aging. Some harmful side effects 

already have been discovered and additional 

research may uncover others.

People with genuine deficiencies of hormones 

should consult with their doctors about supplements. Talk to your doctor if you are interested 

in any form of hormone supplementation or 

“anti-aging” approaches beyond healthy diet 

and physical activity. Meanwhile, people who 

choose to take any hormone supplement without 

a doctor’s supervision should be aware that 

these supplements appear to have few clear-cut 

benefits for healthy individuals and no proven 

influence on the aging process. 

For more information on health and aging, 

contact: 

National Institute on Aging 

 Information Center 

P.O. Box 8057 

Gaithersburg, MD 20898-8057 

800-222-2225 (toll-free) 

800-222-4225 (TTY/toll-free) 

www.nia.nih.gov 

www.nia.nih.gov/Espanol

To order publications (in English or Spanish) or sign up for regular email alerts, go to:

www.nia.nih.gov/HealthInformation

april 2008