High IGF1 level

My blood level IGF1 level is high, normal range is between 49 & 209 ng/ml
but mine is 293. i am on rapamycin Zydus brand for past 3 months on 6mg a week dose.
my post and pre treatment level is same on rapamycin dose.
how long does it take IGF1 to come down ?
can i do anything else to bring my IGF1 to within normal range.
Endo confirmed i don’t have acromegaly using GH stimulation test

thank you


Hi Imran, thanks for posting. That is interesting. When are you testing your IGF1 levels, with respect to when you are taking the rapamycin?

Rapamycin should likely lower your IGF-1 levels, at least during the first few days after taking it.

What was your IGF-1 level prior to taking rapamycin? Did you ever test it?

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My IGF-1 levels is always been on high side tracking for past 3 yrs, i was unsure how to treat it , so i wanted to try rapamycin with no benefit so far.

Before Rapa IGF-1 Oct 2021 - 283 ng (6mg a week)
started rapamycin - 1st week of December 2021 - 21March 2022
After Rapa IGF-1 March 21st 2022 - 293 ng

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I’d test the peak sirolimus levels after a dose to be sure you are getting it into your bloodstream. See this for the LEF sirolimus test:

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Selenium supplementation inhibits IGF-1 signaling and confers methionine restriction-like healthspan benefits to mice | eLife According to this article selenium supplementation lowers IGF-I levels in rat models.


Can’t you have high IGF1 levels and low IGF1R levels? The body may compensate for reduction in one by increasing the other


let me check if blood test is available for IGF1R & Sirolimus test in india and will add selenium to my supplement stack

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You ought to check your Selenium level first - sure, too little impacts ability to absorb nutrients, but too much can be toxic.
Selenium levels are highly variable across the whole population - you might find you are perfectly ok with your level.


good point will add selenium to blood test list

I have high normal testosterone yet I don’t grow a ton of muscle very quickly or have any clinical symptoms that would suggest too much or too little. High-normal serum doesn’t necessarily equal abnormal.

Check with your endocrinologist.

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FWIW, have you tested your insulin levels? High IGF1 can be associated with diabetes/insulin resistance/metabolic disorders. What is your A1C? I used to have high IGF-1 and high inflammation. What helped me was going low carb and intermittent fasting.

Here is the effect on IGF1 and Sirolimus blood levels with LEF blood tests that I saw from 15mg Rapamycin every other week:

  1. Feb 17 (2 weeks after my last dose of Rapamycin and 12 hours fast) : IGF1 = 167 ng/ml, Sirolimus < 0.5 ng/ml. Fasting Insulin was 4.5uIU/ml, and A1C was 5.6. I am Type II diabetic, but take Metformin 2x500mg/day + Mounjaro 5mg/week.

  2. Feb 20 (2 hours after 15mg Rapamycin & 12 hours fast, no GFJ or other supplements known to improve absorption of Rapamycin within 24 hours) : IGF1 = 146 ng/ml, Sirolimus = 13.9 ng/ml

Others have reported peak Sirolimus blood levels scaling roughly 1ng/ml per 1mg of Rapamycin without GFJ or other absorption aids. In my case the Rapamycin is the Rapacan brand ordered from India from dropshipmd.com.

I am not sure what the typical drop in IGF1 is supposed to be or if the effect on IGF1 is maximum when Sirolimus blood level peaks (typically 1-2 hours after intake) or takes more time to fully kick in.

Update : Mar 3 (2 hours after 18mg Rapamycin & 12 hours fast, no GFJ or other supplements known to improve absorption of Rapamycing within 24 hours) : IGF1 = 126 ng/ml, Sirolimus = 49.5 ng/ml. Not sure why my Sirolimus numbers are so much higher than on Feb 20.


Wonder if further reduction of A1C will help lower IGF1. Metformin has shown to reduce IGF1 and you have room to the upper limit of 2,000mg. Can’t tell your body fat percentage, but there seems to be a correlation. Long water fasting and Keto helped me drop initial weight. 2,000mg of metformin helped me drop the final pounds (I’m prediabetic). Sorry, but I have not repeated my IGF1 test for over 5 years.

Study of almost 400,000 confirms that higher blood levels of IGF-1 are a risk factor for several types of cancer

I am speaking off the cuff here without doing any research, but doesn’t IGF-1 activate/increase Mtor, not the other way around? So decreasing the downstream target of IGF-1,MTOR, may not have any effect on reducing IGf-1…. from my experience male hormones increase IGF-I, ie testosterone and DHEA, GH increases it greatly, and carbs increase it, with protein and food also having a slight effect. I don’t feel like having an all protein diet increases it crazily like some of these people say. I actually have low IGF-I levels myself naturally, like 70-ish, And taking 15-25 mg of the DHEA seems to raise it over 100… I personally don’t feel as good when my IGF-I is that low, it’s hard to explain…

Obviously, having raised levels is not good either. I don’t think around 150 like the person above is horrible, from my recollection those studies involve a level over 200, maybe even 300…

Sorry, didn’t mean to hijack this thread : I am not the one with the high IGF-1 of 293, I just posted my numbers after taking Rapa, to show that it does have a small immediate lowering effect.

I recently learned that the the Labcorp IGF1 blood test can be inaccurate if supplementing with Biotin (Vitamin B7), which is present in most multivitamins and Vitamin B formulations : These need to be discontinued 72 hours before blood draw to get an accurate IGF1 value. I saw this warning at marekdiagnostics.com, the site recommended in another thread for the lowest cost $59 (Labcorp) blood test for Sirolimus. This also affects most Labcorp hormone tests (eg T3,T4, Testosterone, Estradiol, FSH, LH, SHBG) except for the more expensive high sensitivity versions based on LC-MS technology.

Do NOT discontinue Biotin if it has been prescribed by a doctor. Some cancer drugs (also Metotraxate used for Arthritis) require large doses of Biotin to minimize damage to non-cancer cells, and discontinuing Biotin can be dangerous.

You can get an LC-MS version of IGF1, that is NOT sensitive to Biotin, from Quest Labs (Ultralabtests.com offers it for $69 + $8 blood draw fee). The regular Labcorp version that is sensitive to Biotin is $75 from LEF or $39 + $5 from marekdiagnostics.com.

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