Hematocrit gone up

I started TRT 6mo again. Everything has been great so far.

My Hematocrit went up from 43.8% (before TRT) to 47.5% (3mo), to 48.4% (6mo). If it goes up again, it seems it will go beyond the range.

My Dr says everything is great. Should I be concerned about Hematocrit? It will be a real pain in the ass if I have to give blood eventually.

I'd appreciate if anyone can share your experience.


Sept 2014 (before TRT)
Hematocrit 43.8 % 37.0-49.0

Dec 2014 (3 month TRT_
Hematocrit 47.5 % 37.0-49.0

Mar 2015 (6 month TRT)
Hematocrit 48.4 % 37.0-49.0

RJTX said:

I started TRT 6mo again. Everything has been great so far.

My Hematocrit went up from 43.8% (before TRT) to 47.5% (3mo), to 48.4% (6mo). If it goes up again, it seems it will go beyond the range.

My Dr says everything is great. Should I be concerned about Hematocrit? It will be a real pain in the ass if I have to give blood eventually.

I'd appreciate if anyone can share your experience.


Sept 2014 (before TRT)
Hematocrit 43.8 % 37.0-49.0

Dec 2014 (3 month TRT_
Hematocrit 47.5 % 37.0-49.0

Mar 2015 (6 month TRT)
Hematocrit 48.4 % 37.0-49.0

Click to expand...

Why not give blood now, proactively? Buy yourself some peace of mind and help someone else. Congratulations on your success in other aspects of your treatment.

RJTX Hi, I think your levels normally go up in the first year, hopefully it won't become a problem, or if you like you can give blood like CoastWatcher mentioned.

Hematocrit may stabilize after long term testosterone replacement

Although this study was done in mice, it may explain why hematocrit may eventually decrease and stabilize in men on TRT. I am one of those men who only went for therapeutic phlebotomy twice. There seems to be an adaptive mechanism that makes red blood cells hange form while hematocrit stabilizes.

Guo W, Bachman E, Vogel J, Li M, Peng L, et al. The Effects of Short-Term and Long-Term Testosterone Supplementation on Blood Viscosity and Erythrocyte Deformability in Healthy Adult Mice. Endocrinology.http://press.endocrine.org/doi/abs/10.1210/en.2014-1784


Testosterone treatment induces erythrocytosis that could potentially affect blood viscosity and cardiovascular risk. We thus investigated the effects of testosterone administration on blood viscosity and erythrocyte deformability using mouse models.


Blood viscosity, erythrocyte deformability, and hematocrits were measured in normal male and female mice, as well as in females and castrated males after short-term (2-weeks) and long-term (5-7 months) testosterone intervention (50 mg/kg, weekly).


Castrated males for long-term intervention were studied in parallel with the normal males to assess the effect of long-term testosterone deprivation. An additional short-term intervention study was conducted in females with a lower testosterone dose (5 mg/kg).


Our results indicate no rheological difference among normal males, females, and castrated males at steady-state.


Short-term high dose testosterone increased hematocrit and whole blood viscosity in both females and castrated males. This effect diminished after long-term treatment, in association with increased erythrocyte deformability in the testosterone-treated mice, suggesting the presence of adaptive mechanism.


Considering that cardiovascular events in human trials are seen early after intervention, rheological changes as potential mediator of vascular events warrant further investigation.

thank you all for your replies! they are very helpful.