"compliment the increase of LH production from the Cordyceps, this compound acts to increase the responsiveness of the Leydig cells which use the LH to produce testosterone. These two components work together to jumpstart the Testosterone Feedback Loop back into production and finding your body's delicate balance. L-Histadine is a direct precursor to histamine which is an important component in the production of the testosterone activators and has been shown to increase the responsiveness of Leydig cells."Although there is no scientific evidence that oral L-histadine (according to my research this is identical to l-histidine, cf. servinghistory.com) supplementation will increase LH and thus the release of androgens, there is scientific evidence for reduced testosterone levels upon administration of anti-histaminica (anti-allergic). With histamine being a histidine-metabolite, this is yet only secondary evidence for the role of l-histidine in LH-release.
Digging further I stumbled across a 1984 study published in Endocronology [Barnea. 1984] discussing the stimulating effect of copper-amino acid complexes in general and CuHistidine (structure on the left, [Modern Drug Discovery]) as well as CuCysteine on GnHR-release of isolated hypothalamic granules. Although, this is an in-vitro study and it can not be considered direct evidence for the use of copper + chelating amino acids to increase hypothalamic GnRH-, pituitary LH- and gonodal androgen-release, a 56% and 63% increase in GnRH is substantial enough to have an eye on appropriate intakes of copper, histidine and cysteine. With reference to the mechanism of GnRH (formerly known as LHRH) release by copper chelates, the authors of a previous study remark:
"We propose that copper may affect LHRH release as follows: copper, bound to an intracellular chelator (protein, peptide, or amino acid), oxidizes thiols of the LHRH granule, leading to a change in granule-membrane permeability and hence to LHRH release." [Rice, 1983]With the high amount of histidine and cysteine in high-protein foods only few health conscious individuals will show signs of deficiency. In view of the increasing (and often unnecessary) supplementation of zinc and the inhibitory of excessive zinc consumption on copper absorption, it may however worth mentioning that - without sufficient copper intake (RDA = 3mg) - your testosterone booster with ZMA (Zinc + Magnesium + Vitamin B6) may well decrease GnRH, LH and thus testosterone.
As an interesting, yet irrelevant side-note: "[Histidine] helps with the lengthening of orgasms and also more intense sexual enjoyment." [AnyVitamins.com]