Real TRT: testosterone and the next response
A hormone response can be impressive. My question concerns the next observation.
Kisspeptin's unexpected beginning
For a site called Real TRT, the opening scene is unexpectedly far from testosterone. The KISS1 gene entered the literature through melanoma cells and experiments in mice: introducing it into metastatic human melanoma cells suppressed their spread in nude mice, while the cells could still form tumours. That was the finding in 1996. Cancer biology supplied the beginning of this story.
Then came human genetics linking its receptor to failure of puberty. The receptor is a cell's receiving machinery; when this particular one lost function, reproductive maturation was disrupted. The same study reproduced the phenotype in mice. A molecule with that history deserves more curiosity than a label such as testosterone booster can hold.
That awkward origin appeals to me. The testosterone question occupies one chapter of a history that began with tumour spread. Following that history seems more interesting than squeezing the molecule into the word booster.
The testosterone response
The early human result was concrete: in healthy men given intravenous kisspeptin-54, LH rose, with smaller rises in FSH and testosterone. In a later experiment, kisspeptin-10 increased LH pulse frequency, and a higher-rate infusion raised serum testosterone. Those observations give the testosterone question a proper foothold.
The route to that response deserves equal attention. In animal experiments examining the reproductive signal, kisspeptin acted directly on GnRH neurons, the cells releasing a hormone signal upstream in the reproductive system. The human experiments then measured the downstream hormonal response. There is a real biological argument here, with different parts established in different kinds of experiment.
I credit the experimental response. Calling it a lasting solution would require a different argument, built around the people receiving it and the outcomes that matter to them. The testosterone page starts with the actual conditions of the human work, including a group whose response failed to appear.
Repeated exposure
One experiment in women with hypothalamic amenorrhea brings this question into focus. Kisspeptin-54 produced a strong initial LH response, followed by a much smaller response after repeated administration. This was a study in women with that condition, measuring LH; the finding cannot supply a numerical forecast for testosterone in men. It can, however, disturb the easy assumption that an impressive first response will simply recur.
That disturbance improves the question. Duration and repetition have to be investigated in their own right. A study of continuous infusion in women with hypothalamic amenorrhea restored LH pulses at the studied conditions while also finding a fading response at the highest infusion rate. Both findings deserve room on the same page.
I give extra credit to an explanation that can accommodate both the rise and the fade. The repeated-signal page puts those observations beside each other and follows the receptor research behind them.
Sexual desire
There is another temptation in a testosterone discussion: to let the hormone stand for everything someone hopes will change. The kisspeptin trial in men with hypoactive sexual desire disorder examined sexual-processing brain networks, penile tumescence and self-reported desire. That is a more particular set of observations than a general claim about feeling better.
I appreciate that particularity. It gives sexual desire an experimental life of its own. The desire page spends time with the trial and with a later human anxiety experiment, where LH increased but measured state anxiety did not significantly change. The endpoints pull apart usefully.
Real TRT is an editorial site about this corner of the published research. There is no treatment service behind the name. Convincing evidence of durable benefit would win me over; until then, the first result remains worth examining closely, on its own terms.