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How Fast Will Hematocrit and Hemoglobin Rise After Phlebotomy?

Hey guys, based on your personal experience, how quickly did your haematocrit and haemoglobin rise after a blood donation? How quickly did it get back to the numbers you had right before the donation?

Well if it is climbing you probably need to lower your dosage so that it doesn’t climb like that again.

What was your HCT before your draw?

I went from 56 to 50

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Lowering dosage does nothing In regards to hematocrit. If anything I had lower hematocrit on higher dosages. 53 on 100 mg a week. 55 on 80 mg a week.

Its takes like 6 months for your HCT to start going up though. So you could have been low for a few months on a high dose then lowered it and then your body started to raise HCT and rbc

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Mine went from 45 pre TRT to 53 in 3 months after starting.

It really depend how long it took to get to the point of needing to donate, if the dose was excessive from the start and rose quickly, this is a sign the dosage needs a decrease. If it’s a gradual increase, donating blood is a helps others.

Be careful donating too frequently and watch your ferritin levels or you could end up with low ferritin.

I usually see a 3% decrease after donating blood.

I hear ya. I saw a nice 6% decrease. Just wondering now if it’s starts climbing back up.

Lowering the dosage of T will most definitely keep your HCT from rising as quickly or as fast, as that is the reason it rose to begin with.

Question for you CBC experts…

What factors are T levels influencing to raise HCT?

I think I get the RBC elevation (could be wrong and please correct if I am)… More T in the blood stream therefore the body requires more oxygen, which in turn triggers the creation of more RBC’s to carry it. Kind of the same effect as moving to a higher elevation after living at sea level for a long time, except for the oxygen factor in that scenario is not so much the body requiring more oxygen, but rather that less atmospheric oxygen is available at the higher elevation…

But I don’t quite get how the HCT plays out. I know that high doses of test will raise HCT, but I don’t quite get why / what factors drive that?

The reason I ask is because some guys see HCT skyrocket on 100mg/wk, while others will only see a jump to around 51 on supraphysiological doses. What’s the difference between hypothetical guy A and guy B?

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HCT is only a percentage. It’s the result of your RBC times MCV. Some say hemoglobin times 3 but that’s not correct.

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Usually the difference is age. Medical literature shows the older you are the more prone you are to being effected.

I’m not quite convinced on that one. Take for instance myself. I’ll be 42 in a couple of months. I’m on 150mg /wk and my my HCT is only at 47%. I’ve read about some guys in their 30’s who only do 80mg /wk and have had to have a phlebotomy because their HCT has reached the mid 50’s.

Not trying to argue at all, just trying to understand.

Now one point to add, which may be worth considering in the equation, is that I only inject 50mg at once, 3 times a week. I don’t know the protocol for the other guy I read about, but could injection volume be factor?

Personal experience is different than in general. Really hard to take your own personal experience and equate that to what typically happens.

I know guys that are 60 that have been on TRT 20 years and have no problems with HCT, that doesn’t mean that it is not typically older men that have problems with HCT on testosterone.

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Im not just pulling this out of my rear either, the literature is out there. Its been years since I have perused it, but it’s there.

Univariate regression consistently revealed an increased odds of polycythemia with higher trough blood testosterone concentrations, using the three cutpoints (hematocrit in excess of 0.49, 0.50, and 0.51) chosen for the sensitivity analysis (Table 2). Trough blood testosterone concentrations exhibited both the highest odds for polycythemia and the greatest significance amongst all covariables. Age was also a consistent univariate predictor of polycythemia ( P <0.03), whereas smoking history (current versus not) was a significant risk factor only for marked polycythemia ( P =0.04). Duration of treatment was not a risk factor for the development of polycythemia in any model when analyzed as a continuous variable, or dichotomized according to whether treatment duration was more than 1 year, or not (data not shown). Similarly, BMI did not increase the odds of polycythemia when analyzed as a continuous variable, or dichotomized according to whether obesity (BMI>30 kg/m2) was present or not (data not shown).


No I didn’t think that and I apologize if that was in any way implied. I tend to ask a lot of “devils advocate” type questions when I’m trying to understand something. I don’t like just knowing that something is true or not, I want to understand the “why” behind it.

It’s kind of like the whole cigarettes cause cancer thing. I know that it’s common knowledge in 2019, but if something was proven as fact, it would be a fact all the time, and not just some of the time right? I mean I know people that are in their 90’s that have smoked their entire lives and have never gotten cancer. Then again I’ve known others that have never smoked, and died from lung cancer. That kind of thing makes you question the validity of the claim you know? I know that cigarettes CAN cause cancer, but what has yet to be really proven is what other factors have to be present for that to be true. If it were true as an absolute, then every person that smoked would have contracted cancer.

Btw I’m not advocating smoking at all. I smoked for most of my life and I have asthma to show for it. I quit as soon as I was diagnosed and will never smoke another cigarette, I’m just making the point that so much of what we think we know, we really don’t. I don’t think we really understand something until we can completely nail down the ins and outs of a thing, and reproduce the results consistently time after time.

Anyway, a little peek into the warped mind of bmbrady77! Lol

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Stimulates erythropoietin.


And now that we are on the subject, it has been a while since I discussed this stuff in this much depth, it seems to me we can extrapolate that injecting too frequently can increase your risk of polycythemia?


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Lmao! I’ll leave that debate to you experts. I can’t even spell the word, much less have an intelligent discussion about it!

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Also these tests should be taken with a grain of salt. Like no way my hematocrit went up 4% in 3 days then dropped 5% 3 days later.