DHEA

Dehydroepiandrosterone (DHEA)* is produced by the adrenal cortex (65). It is the most abundant steroid in the human body (66,67) and yet it's function and mechanisms of action remain largely unknown (68,69). No receptor has been identified (68,69) and it is thought that it acts both centrally as a neurosteroid (70,71,72), and peripherally via conversion to androgens and oestrogens (73,74). Peripheral intracellular conversion to androgens may be significant, having been estimated to contribute more than 30% of total androgens in men (75).

DHEA levels peak in one's twenties and then decline with age, levels beyond age 70 years being less than 10% of peak values (76). Low DHEA, or low DHEA:cortisol ratios have been associated with:

Cardiovascular disease (77,78,79)
Oxidation of LDL, potentially contributing to atherogenesis (80)
Low functional independence in the extreme elderly (81)
Inflammatory diseases (82,83,84)
Depression (85,86)
Cognitive decline (87)
Erectile dysfunction (88)

However, association is not causation and falling DHEA with age may be simply tracking the pathologies of aging rather than causing them. Moreover, no suitable animal model for study of DHEA exists (89), because laboratory animals, particularly rodents, have such low DHEA concentrations that any exogenously supplied DHEA represents a pharmacological rather than a physiological dose (90). Hence, caution is warranted when extrapolating animal DHEA findings to humans.

These difficulties notwithstanding, DHEA replacement to physiological levels in humans has demonstrated:

Improvements in psychological well-being (91,92,93)
Improvements in depression (94,95)
Increased IGF-1 levels (91,96,97)
Favourable immunomodulation (97) including suppression of the pro-inflammatory cytokine IL-6 (98)
Improvements in erectile dysfunction (99,100)
Beneficial effects on skin pigmentation, hydration, and thickness (101)

Physiological DHEA replacement has also been demonstrated to favourably affect body composition in elderly (96,102) but not young men (103,104). Furthermore, DHEA does not significantly raise testosterone levels in men (68,73,91,92,101,103,105,106). However, the intracrine conversion of DHEA may contribute significantly to total androgens without actually raising serum androgen levels (73,74,75).

DHEA replacement can significantly elevate oestrogen levels, though they remain within the normal physiological range (68,101,105,106). This may be beneficial or detrimental, depending upon one's personal hormonal milieu.

For these reasons we recommend that men replacing DHEA should use Androbalance test kits to help fine-tune their dosage. They should also monitor additional hormones, particularly oestradiol, to ensure that the supplementary DHEA follows a healthy metabolic pathway.

*For simplicity DHEA here is taken to mean the sum of DHEA and it's sulphated form DHEAS