Low white blood cell count

I just received blood work results and everything looked good except that I had a low white blood cell count. Prior to taking rapamycin this test was always within normal range. Has anyone else experienced this? Could this mean that I am taking a higher dose of rapamycin than would be ideal?


Can you share the exact pre and post WBC count / measure?

Prior to taking rapamycin WBC was 5.2 (Labcorp ref. range given as 3.4 - 10.8
After taking rapamycin WBC is 2.7


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That is pretty low. Per this video series What Is the Ideal White Blood Cell Count? | NutritionFacts.org
Dr Greger argues that lower total white blood cells can be a marker of lower systemic inflammation and better physical fitness, but even his lower suggested “normal” cutoff is 3.


Without a reasonable number of prior measurements it is difficult to say what your personal ‘normal’ range is. If you only have two measurements, then it could be that your 5.2 reading is on the high end of your range and 2.7 could be the low or near normal value for you.

Personally speaking, I hover around 3.0 for WBC (along w/ neutropenia) and occasionally dropping to 2.7 like you, but that jumps when I have an obvious infection and it doesn’t appear to hinder an immune response to covid vaccination by way of titer measurement. There does appear to be a correlation between the amount of exercise and my WBC with greater amount and frequency of exercise associated with lower WBC. That said, low WBC along w/ a mutation in one copy of methionine synthase gene resulting in only one functional copy are two main reasons why I am hesitant to trial rapamycin at the moment.


Actually I do have numerous measurement going back several years and 5.1 to 5.6 had been my normal reading. But I am glad I received the information in these posts. Apparently, some of the decrease could be because of positive effects of rapamycin (ie decreased inflammation, etc.). I believe my PCP has made more of this than necessary. I would however like to get an idea if decreasing the amount of rapamycin I am taking would lead to the WBC count increasing.


are you taking 6mg/wk or following other schedule?

I had taken 6mg/week for half a year. I am currently taking (for the last two months) 10mg/week. There have been no noticeable negative side effects. I have experienced some positive effects.


Yes. This was what I was told by someone extremely familiar with Rapamycin. "The low lymphocytes are almost certainly caused by the rapa. Rapamycin is extremely good at inhibiting proliferation of lymphocytes. That’s one of the main reasons why they use it to prevent rejection of organ transplants.

I would keep a very close eye on this, especially in the middle of a viral pandemic. You don’t want this to be low right now. Lymphocytes are very important in mounting a defense against viruses, and in getting a good response to a vaccine". I have suspended my use of Rapa for the time being in order to try to build my lynphocytes to a healthy level. Was your CRP also high?


You are right to be cautious However all the evidence is that rapa boosts immunity to viruses. The one clinical trial in humans at Glaxo showed that reaction to the flu virus increased dramatically on rapa and even lasted after it was discontinued.

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Ozone8 on this website posted on Nov. 2 “My recent CBC showed a WBC of only 2.4 . While I’ve always been on the low end, that was a surprise”.

Interesting results that people are seeing with this. My WBC measurement has actually gone up the past two years I’ve been on rapamycin. Was 4.9 after 5 or 6 months (dosing was slowly increased from 1 to 6 mg/week). This summer it was at 5.3, and I’ve been dosing at about 10mg / wk most of the year.

First, thanks for sharing. I just completed a nine +week regime. Based on my own research, I decided to use the high dose pulse method 10 mg once per week. After the first two weeks, I switched to 8-10 days between doses as sort of a compromise between those who say to dose weekly and those who say to dose every two weeks. (14 days is the approx. 5 half-lives in the human system)

I bought 100, 1 mg tablets and used 90 for myself and 10 for my aged cat. I dosed my cat weekly.

After finishing, I had blood work done.
During, 8/25/21 WBC = 9.8 This was while I was taking Rapamycin.
11/23/22 WBC =7.9 This was approx. 4 wks after the last dose.

As you can see my white blood cell count has dropped from the last check, however, my white blood cell count has fluctuated in the past so it’s hard to tell if this is a one-time thing or not. Something to keep an eye on.

I plan to repeat the same dosages in January pulsing 10 mg Sirolimus every 12 days.

I won’t go into the many details here, but my cat and I are very enthusiastic about the results.

I am 80 yrs old, my cat is 14.


2 posts were split to a new topic: Rapamycin for my Cats?

I’m not sure if the topic is still about rapamycin caused low WBC counts. In any case, I am able to use the very strong correlation I have with rapamycin dose and WBC count to monitor my rapamycin dose. With a weekly dose of 8 mg my white blood cell count is just barely in the low end of normal range. A higher dose causes further lowering of the WBC count so I stick with 8 mg. The needed test, complete blood count is inexpensive and easily obtained.


My WBC is 3.4 after 3 weeks of Rapa. It fluctuates between 3.5-7 off Rapa. So nothing to report. My Neotrophils were low at 1.70. Previously my low was 1.79.

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Hi everyone. My WBC is typically borderline low/below limit over the last 10 years (age 59 now). My new longevity doctor won’t prescribe Rapa because he says my WBC is too low. It seems like some of you are doing fine below 4.0 WBC. My goal is to do the 5mg/week regimen. Do you think this WBC is too low to start Rapa? Do you recommend starting at a lower dose (eg 2mg/week) and then testing the WBC to see how it goes? Thanks!

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Rapamycin does not necessarily lower WBC count. If you have been doing fine at this level, experiment with rapa to see if it goes down. If it does go down, surely it will return to your normal level once you stop rapa. IANAD, but I say “go for it.” Just test WBC within a few months.

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My experience over the last few months with rapamycin and WBC has has been a lowering initially and a gradual return to normal in a couple of months. For me normal is the low end of normal for the population at large - sounds a lot like your situation. My advice therefore is much the same as EnrQay’s, Experiment and monitor. A figure in the threes or even high twos is not necessarily a bad thing. I would check the level frequently as a “complete blood count” is a quick and easily obtained test that is economical… I do think that should you develop an infection you should at least temporarily stop rapamycin and get the infection treated. I believe Dr. Green has had some trouble with infections. I never had.