200mg DHEA is near the upper limit of what is used to boost testosterone. DHEA is very well studied, and appears to boost testosterone most of the time in persons older than 40 years of age.
Usage of 200mg DHEA in youth (18-25, for the most part) is much more hit or miss. It has been noted in some studies, but some studies also come back null. The DHEA pool always rises (indicating absorption), just sometimes this does not translate into higher testosterone levels for unknown reasons.
It does boost testosterone in women as well, but estrogen too. Minimal to no side-effects regarding androgenicity (man-like side effects) are seen with the average dose of 50mg in women, which is what many fat burning and anti-aging supplements contain.
Females may also use the derivative compoun called 7-Keto (or 7-Oxo), which is a metabolite of DHEA that cannot turn into either estrogen or androgens.
One human study of 14 days noted an increase in testosterone, whereas a study lasting longer than that failed to note an increase; it is possible the body regulates testosterone increases from D-aspartic acid.
Usage should, at least until more research is conducted, be limited to short term use or used by infertile men (of which this negative regulation may not exist).
At least one study of 3,000 IU has noted an increase in testosterone concentrations in men with low vitamin D status, and a followup in men with normal vitamin D status failed to replicate this information.
It appears that a deficiency of vitamin D suppresses testosterone production and normalizing this deficiency normalizes testosterone; supraphysiological levels of vitamin D do not appear to be further beneficial.
A deficiency of zinc reduces testosterone concentrations in serum, and normalizing this deficiency causes a compensatory increase; zinc supplementation does not increase testosterone above baseline.
Fenugreek has been shown to increase testosterone in healthy males, which is thought to be due to a backlog of testosterone conversion into DHT via inhibiting the 5-alpha reductase enzyme. The reduction in DHT needs to be considered though, as many persons wishing to increase testosterone (for libido or muscle building) would also prefer an increase in DHT.