This is the study that shows an apparent half-life of ten days (239.63 hours). They don't say how it was calculated. It seems a little long compared to what can be derived from the average Cmax and Cmin values.@Cataceous, I definitely think you are correct that Xyosted has different pharmacokinetics compared with other forms of enanthate. But, I was thinking about the phase II study they published in 2015. I am not sure how to post papers, but the title is:
Pharmacokinetic Profile of Subcutaneous Testosterone
Enanthate Delivered via a Novel, Prefilled Single-Use Autoinjector: A Phase II Study
In this study, they show a graph in which the peak levels with 50mg stay the same over six weeks, and they state: "The 50-mg dose exhibited no accumulation between doses...
suggesting that clearance exceeds exposure by the end of the dosing interval
". I would assume that if the half life were 7 days or less, that the peaks would gradually rise, or is this flawed thinking? I also finding it a little odd that, if this is true, they even offer 50mg. Why would someone want troughs that land them in the same sub therapeutic range every week?
Their website claims that the peaks and troughs stay in a 1.8x ratio with each other, suggesting peaks are nearly double the trough levels. So, if your trough is 500, you peak should be around 900. Does anyone know if this therapeutic window is tighter than other esters, or is it similar?
Predict estradiol, DHT, and free testosterone levels based on total testosterone
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A form of estrogen produced from testosterone. Important for bone health, mood, and libido. Too high can cause side effects; too low can affect well-being.
Dihydrotestosterone is a potent androgen derived from testosterone. Affects hair growth, prostate health, and masculinization effects.
The biologically active form of testosterone not bound to proteins. Directly available for cellular uptake and biological effects.
Lakshman KM, Kaplan B, Travison TG, Basaria S, Knapp PE, Singh AB, LaValley MP, Mazer NA, Bhasin S. The effects of injected testosterone dose and age on the conversion of testosterone to estradiol and dihydrotestosterone in young and older men. J Clin Endocrinol Metab. 2010 Aug;95(8):3955-64.
DOI: 10.1210/jc.2010-0102 | PMID: 20534765 | PMCID: PMC2913038