Here's some interesting stuff I copied from another source:
DHEA is a naturally-occurring substance and is quite safe when taken in doses not exceeding 50 mg per day for women and 100 mg per day for men. In earlier research studies the doses of DHEA were very high, up to 3,000 mg per day, but with minimal side effects nevertheless. Some practitioners routinely give up to 200 mg per day without any problems. It is only necessary to restore DHEA to levels normally present when young to achieve optimal benefit.
To understand DHEA and its functions, it is helpful to first have a general understanding of the seven major glandular centers in the body and their interrelated actions.
The endocrine glands release tiny amounts of hormones into the blood stream, which govern cellular activity in all cells and organs of the body. Those glands are mainly centered in seven anatomical locations. The lowest and first set of glands produces the sex hormones. They also make the sperm and ovum for reproduction. Sex hormones are made from a steroid nucleus, which comes from DHEA, which in turn comes from cholesterol. Without cholesterol we would be deficient in many vital hormones. Cholesterol is necessary and is unjustly maligned.
In addition to causing anatomical and functional differences between males and females, the sex hormones are also potent anabolic steroids. In other words, they support protein synthesis, bone structure, skin tone, muscle strength, neural networks in the brain, and many aspects of strength and vitality. The sex hormones include estrogen and progesterone in women and testosterone in men, although women make some male hormones and men make some female hormones in much smaller amounts.
Moving upwards in the body, the second level of hormone production is in the uterus of women and the prostate gland of men. Those areas are closely related to the sex hormones. During pregnancy, the uterus produces massive amounts of progesterone and also estrogen. The prostate produces various constituents of semen and also contains a tiny vestige of a uterus that never develops further in men.
The third area of hormone production is just below the waist and includes the adrenal glands on the left and right and the pancreas in the center, associated with a large plexus of nerves. The core of the adrenal glands produce adrenaline, the fight-and-flight hormone. On the outer layer or cortex, the adrenal glands produce a variety of steroid hormones, using DHEA as a raw material. Those hormones include aldosterone, which preserves minerals in the body, and cortisone, which controls immune responses and also affects energy and mineral metabolism. The adrenal glands also make both male and female sex hormones, but in much lower amounts than the reproductive organs.
It is primarily in the adrenal cortex that cholesterol is made into DHEA. DHEA then becomes the source for all other adrenal cortical hormones as well as sex hormones in the reproductive organs. DHEA is thus a vital raw material for hormone production. DHEA declines steadily with age in everyone. From age 20 onward, production of DHEA decreases until at age 80 only ten percent or so of earlier levels persist. Because many benefits experienced from taking DHEA supplementation by mouth are unique, and cannot be attributed to the other hormones which are made from DHEA, DHEA itself has been shown to have direct effects on the body, not just as a raw material.
DHEA production varies widely from person to person. Some people seem to maintain youthful levels into later life while some young people exhaust their adrenals and become deficient in DHEA at a young age. Chronic illness or major stress depletes DHEA at a younger age.
When taken by mouth, DHEA is rapidly absorbed into the circulation and converted to its storage form DHEA-S. DHEA levels themselves fluctuate widely during the day and from day to day, depending on stress levels and the need to manufacture other hormones. DHEA is stored in a reservoir of DHEA-Sulfate (abbreviated DHEA-S), which remains relatively constant from day to day. DHEA-S blood levels therefore reflect the overall adequacy of DHEA. Measurements of DHEA-S in blood are used as the most reliable indicator of DHEA metabolism. Saliva and urine have also been used but are not as reliable.
The fourth hormone-producing center, moving further up in the body, is in the chest, behind the heart. This called the thymus gland. The thymus controls the body's immunity. A type of white blood cell, called a lymphocyte, is produced and stimulated by the thymus to make antibodies and to recognize and destroy disease-causing viruses, bacteria, funguses, yeast, parasites, and other undesirable substances which are foreign to the body. The thymus produces hormones and other factors which in turn cause white blood cells to clean up and dispose of unwanted invaders and potential toxins.
The thymus gland is the size of a plum in adolescence. At puberty it begins to shrink and eventually becomes the size of a small raisin in old age. Resistance to infection and other aspects of youthful vitality diminish with this decrease in the thymus gland. DHEA slows and partially reverses the loss of thymus activity in later adulthood.
Higher up in the body we come to the fifth glandular area, the thyroid. Thyroid hormone controls production of energy in cells, as fuel from food and stored fat is combined with oxygen to release chemical energy for metabolism; including growth, healing, warmth, movement, strength, circulation, and brain function. Thyroid sometimes diminishes with age and levels are easily measured in the laboratory. Thyroid can be replaced by mouth with natural thyroid extracts, which are only available by prescription.
The sixth glandular level is the pineal, which makes melatonin from serotonin for proper sleep and dreams. Melatonin is converted to other substances in the brain, which are important for visualization and imagination. Melatonin has recently been shown to be an effective free-radical scavenger, an anti-oxidant, and slows and prevents premature aging and cancer.
The master gland at the seventh level is called the pituitary. The pituitary is an extension of the hypothalamus, at the base of the midbrain. The hypothalamus signals the pituitary to release tiny amounts of many different controlling hormones, which in turn affect the hormone output of the six lower glandular centers described above. TSH (Thyroid Stimulating Hormone) from the pituitary governs output of the thyroid gland. ACTH (Adrenal Cortical Stimulating Hormone) governs output of specific adrenal cortical hormones by the adrenal gland. Other pituitary hormones regulate production of sex hormones (estrogen and testosterone), and control the monthly female reproductive cycle.
Sensors in the hypothalamus detect circulating blood levels of the many specific hormones and signal the pituitary to turn up or turn down production by the lower centers as needed. This is much like the action of a thermostat upstairs sending a signal to the furnace on a lower level to produce more heat when the temperature drops. In fact, thyroid hormone does produce heat in the body and is controlled in exactly that way by the pituitary.
As far as virilization is concerned, it's really not a concern. Your wife isn't taking a steroid, or a prohormone steroid, she is taking a naturally occurring precursor. Because dhea is a naturally occurring substance in the body, and the human body (being very smart) will store what it needs, convert what it needs, and urinate out the rest, the chances for negative side effects are slim to none when taken in moderate doses.
If your wife's body "needs" a little extra T (according to her HPTA axis) her adrenals will produce it from the additional dhea, if not, she won't.