DHEA (dehydroepiandrosterone) is a precursor steroid hormone to androgenic and estrogenic hormones synthesized in human gonads.
Low levels of DHEA are associated with the pathophysiology of age-related diseases and impaired cognitive functions.
It is sometimes referred to as a ‘fountain of youth hormone as it is believed to have a role in longevity and improving quality of life.    
Health Benefits of DHEA Supplements
The key benefits of the DHEA supplements include enhancing ovarian function in women with less ovarian reserves and increasing bone mineral density in older women. It may improve depression, sexual functions, mood, and well being. Little evidence suggests that it may modulate serum lipid markers, cognitive functions, and endocrine parameters in menopausal women.
1. DHEA supplements improved ovarian function in women with diminished ovarian reserves
DHEA supplementation improved ovarian function and IVF outcomes in women with diminished ovarian reserves.  
In a study involving 25 patients with diminished ovarian reserves and who underwent IVF cycle, DHEA supplementation (75 mg) showed an increase in fertilized oocytes, embryos transferred, and average embryo scores per oocyte.
Supplementation of DHEA showed a significant increase in oocytes retrieved, rate of fertilization, and the total number of embryos available.
A systematic review showed that DHEA supplementation reduced the likelihood of abortion.
It also increased the rate of live births.
What it means: DHEA supplementation improved the rate of pregnancies, increased live birth rate, and decreased the likelihood of abortion in women with a history of failed IVF cycles. Future studies will determine mechanisms of action by which DHEA improves ovarian function.
2. DHEA supplements may increase bone mineral density and reduce bone resorption
DHEA supplementation may improve bone mineral density and reduce bone resorption in women, as low levels of DHEA were linked to losses in bone mineral density.  
A placebo-controlled study showed that 50mg of oral DHEA had a positive effect on lumbar spine bone mineral density in women aged 55 to 85 years.
In another study, oral DHEA supplementation with vitamin D and calcium improved spine bone mineral density in women.
Some studies showed that DHEA supplementation did not have any effect on bone mineral density. 
What it means: Some studies showed that DHEA supplementation might improve bone mineral density and reduce bone resorption in women over 50 years. More studies are required to assess the efficacy of DHEA supplementation on bone mineral density and bone resorption.
3. DHEA supplements may reduce depressive symptoms
Studies reported that DHEA supplementation might improve depressive symptoms. Lower levels of DHEA was associated with depression, and therefore, DHEA supplementation may improve depressive symptoms.  
A systematic review showed that DHEA supplementation reduced depressive symptoms in patients with Schizophrenia, anorexia nervosa, HIV, and adrenal insufficiency.
In a study with subjects ranging from 55 to 85 years, DHEA supplementation decreased the Beck depression inventory score. It did not have any benefit on cognitive performance.
A study involving patients with major depression, 90mg/day of DHEA, decreased the Hamilton depression scale. 5/11 patients showed a 50% decrease in depressive symptoms.
What it means: DHEA supplementation may have a modest antidepressant effect. Further, large scale studies are warranted to study the antidepressive effects of DHEA and evaluate if DHEA can be used for the treatment of depression.
4. DHEA supplements may improve sexual functions in women and erectile dysfunction in male
Some studies showed that DHEA supplementation might improve sexual functions and libido in postmenopausal women with impaired sexual function. It may also treat erectile dysfunction in men.
In a study with postmenopausal women, 10mg of DHEA supplementation daily for a year enhanced sexual function and libido.  
Oral DHEA treatment improved erectile dysfunction in male patients with hypertension or without organic etiology. 
DHEA supplementation did not improve sexual symptoms in postmenopausal women with normal adrenal function.
What it means: DHEA supplementation may improve sexual functions in postmenopausal women with adrenal insufficiency. It may help with treating erectile dysfunction in men without organic etiology and with hypertension. More studies are required to evaluate the molecular mechanisms of DHEA in improving sexual functions.
5. DHEA supplements may improve mood and mental well being
Studies showed that DHEA supplementation might improve mood and mental well being in patients with adrenal insufficiency. 
A USA study showed that DHEA supplementation improved well being in 67% men and 82% women.
In a randomized controlled study involving hypopituitary adults, DHEA supplementation enhanced psychological well being.
It increased social functioning and general health perception in females. Men showed better scores in self-esteem and depression.
A study showed that 50 mg of oral DHEA for 12 weeks improved mood, fatigue, and overall well being in Addison disease patients.
What it means: DHEA supplementation may improve psychological well being in women and men with adrenal insufficiency. Long term studies are required to determine the role of DHEA as a therapeutic agent for treating mood disorders.
6. DHEA supplements may modulate serum lipid markers
Some studies showed that DHEA supplementation might modulate lipid markers. It may show a downward trend in LDL, VLDL cholesterol, and triglycerides levels.  
10% DHEA cream decreased total cholesterol and plasma HDL levels.
Oral DHEA therapy reduced HDL cholesterol and fasting triglycerides in women and men aged 60-88 years.
Short term DHEA administration reduced serum LDL cholesterol levels.
A study showed that 50mg of DHEA supplementation for three months did not improve lipid metabolism or glucose parameters. 
What it means: Some studies showed that DHEA supplementation might decrease total cholesterol concentration. These lipid-modifying effects of DHEA remain uncertain. Large scale randomized controlled studies are required to elucidate optimal dosing required for DHEA to produce a hypolipemic effect.
7. DHEA supplements may enhance cognitive function in elderly women
Few studies showed that DHEA supplementation might improve cognitive function in older women.
A study showed that DHEA supplementation increased cognitive scores, verbal fluency, and maintained activities of the daily living score in women aged 65-90 years.
In a study involving older men and women, two weeks DHEA supplementation improved mood, well being, and cognitive score in women.
Some studies showed that DHEA supplementation did not improve cognition or well being in subjects. 
What it means: Some studies showed that DHEA supplementation might improve cognition and well being in older women. According to the Cochrane review, there is inconsistent evidence about the use of DHEA for enhancing cognitive function. Future, large trials with a longer and shorter dose of DHEA are required to evaluate its cognition-enhancing properties.
8. DHEA supplements may improve endocrine parameters in menopausal women
Studies showed that DHEA supplementation might improve endocrine parameters in menopausal women.  
Administration of low dose (25mg) of DHEA increased plasma levels of steroids in postmenopausal women.
It reduced climateric symptoms.
A pilot study showed that DHEA supplementation decreased menopausal hot flashes.
A systematic review showed that there is uncertainty about whether DHEA supplementation improved quality of life or reduced menopausal symptoms. 
What it means: Studies showed that DHEA supplementation might improve the endocrine profile in menopausal women. However, the effect of DHEA supplementation in reducing menopausal symptoms is uncertain. More studies are required to evaluate the usefulness of DHEA supplements in menopausal women.
Possible Side effects of DHEA Supplements
DHEA is possibly safe when taken in recommended doses for the short term. It may cause stomach upset and acne. It also may cause abnormal hair growth (hirsutism) and a deeper voice in women.
Avoid taking DHEA supplements while pregnant or breastfeeding, as it may increase the levels of androgen.
Individuals with an enlarged prostate, diabetes, hormone-sensitive conditions, high cholesterol, liver problems, and PCOS should avoid taking DHEA supplements as it may worsen the condition.
It may also exacerbate psychiatric disorders.
Possible Drug Interactions of DHEA Supplements
It may interact with anastrozole, exemestane, fulvestrant, insulin, letrozole, medications changed by liver, tamoxifen, and triazolam.
Avoid taking DHEA if taking these medications as it might reduce the effectiveness of these drugs.  
There is no optimal recommended dose of DHEA supplements.
Clinical studies used 200mg of DHEA supplement for enhancing testosterone in a young male. Dosage in the range of 25-50mg is effective in adults over 40 years.
The benefit of DHEA on improving muscle strength and physical function remains inconclusive. Some studies showed that DHEA therapy increased muscle mass and strength induced by resistance exercise in elderly subjects.  Some studies showed that DHEA ingestion does not improve muscle mass, testosterone levels in resistance-trained athletes, and older subjects.  
The role of DHEA supplementation in preventing type II diabetes has not been entirely determined. DHEA supplementation may improve glucose tolerance and increase insulin sensitivity in elderly individuals and hypo adrenal women.  Few studies showed that DHEA supplementation does not alter blood glucose levels.   These inconsistent results are to be verified by future studies.
Preliminary evidence showed that the topical application of DHEA might reduce the appearance of aging skin, which warrants further investigation.
A pilot study showed that the topical formulation of DHEA increased the rate of sebum, improve skin brightness, and counteract papery appearance. Another study showed that DHEA might improve collagen biosynthesis and modulate keratinocyte metabolism.
Studies reported that DHEA supplementation might improve sleep quality.
In 10 healthy young men, DHEA administration increased rapid eye movement sleep. DHEA’s effects on sleep were dependent on its conversion to androgen and estrogen. The quality of sleep enhanced if testosterone levels increased and dampened if estradiol levels increased. More studies are still required to study its effect.
DHEA supplements are widely used by the general public to prevent complications of aging and menopause. It may have beneficial effects on humans, including adrenal insufficiency, depression, infertility, mood disorders, and osteoporosis.
Additional research studies are required to understand the pharmacological effects of DHEA in humans. Future research will determine if DHEA could be used with conventional therapy and improve the quality of life.