Growth Hormone reference range

[space8]

Hi there!

This might be a long shot, but I was going through some old lab results of mine and happened to see that my GH and IGF-1 had been tested at one point. My IGF-1 seemed to be within the reference range (in the middle somewhat on the lower spectrum).

Though I looked at my GH result and saw it was 0.07 µg/L. I know a single GH test can't be used to diagnose a Growth Hormone deficiency (but neither can a normal IGF-1 exclude it as far as I've understood), but that number seemed a little low to me. There were no reference range since GH secretion is pulsatile.

I read that single values above 3 µg/L could rule out GHD, but do you guys think this could be something to look into or am I grasping at straws? Perhaps GH values close to zero are expected or even desirable. Or perhaps it means nothing due to the pulsatile nature of GH. I know very little about it. I just thought I'd check in.

I'm going to an endocrinologist soon for an unrelated matter and thought I might as well ask about it, but I'm not sure I want to bring it up if it's a completely normal value! What would you say?

 

[Hip]

do you guys think this could be something to look into or am I grasping at straws?

One person (@awkwardlymodern) on this forum was was diagnosed with ME/CFS. After 10 years of illness, she finally found she had growth hormone deficiency, and after starting HGH injections, she was back to near normal in a matter of days, and reached full health after about a month on the injections.

The symptoms of HGH deficiency are listed in this post.



In a test at a London lab, my HGH blood level was 0.5 ug/L. Reference range stated on the test: Up to 0.8 ug/L.

I also tested myself for HGH deficiency by actually buying some injectable HGH and taking that for a week or so. I noticed no benefits.

HGH secretagogues like GHRP-2, hexarelin and MK-677 may not work as a test for deficiency, since @awkwardlymodern also tried these, and noticed no benefits. So maybe if the pituitary is not working well, these secretagogues cannot coax it to secrete HGH.

 

[space8]

Thank you so much for your response, Hip!

I actually came from that thread after searching the forum for any correlations to ME/CFS. I have many symptoms from that HGH deficiency list (including changes in blood cholesterol, episodes of hypoglycemia, increased sensitivity to cold or heat and most of the mental symptoms). Though, I suspect many ME/CFS:ers can relate to symptoms on that list as well, so it's very difficult to tell.

So up to 0.8 ug/L but no lower range. 0.07 ug/L is quite a bit lower than 0.8 but I can't tell if it's clinically significant since it's only one single test in serum. I think mentioning it to my endocrinologist might be a good idea. I'm just worried she'll think I'm being unreasonable. It's always a little shaky bringing up a new theory or something you'd want to rule out.

It would be very interesting to try HGH injections, especially after hearing @awkwardlymodern's story. But it would be good to get it confirmed first. I just don't know how doctors would detect the condition if a single low GH value isn't enough to raise the suspicion and a normal IGF-1 can't exclude GHD. If so it seems to me that they would be relying on the IGF-1 result after all. Perhaps mistakenly so since almost every source says that you can't go off of IGF.

Thank you again!

 

[Hip]

So up to 0.8 ug/L but no lower range. 0.07 ug/L is quite a bit lower than 0.8 but I can't tell if it's clinically significant since it's only one single test in serum.

Yes, it's difficult because of the pulsatile nature of HGH secretion.

This article says the normal range for GH level is typically:

• For adult males -- 0.4 to 10 nanograms per milliliter (ng/mL)
• For adult females -- 1 to 14 ng/mL
• For children -- 10 to 50 ng/mL

ng/mL is the same as μg/L.

So your result of 0.07 μg/L seems low.


I believe the insulin tolerance test is the gold standard for HGH testing.

 

[space8]

Thank you so much for clarifying that ng/mL is the same as μg/L. I was confused when searching online as I have no clue how those measurements are calculated. That's great to know.

It seems quite low as you say. I wonder why the doctor who ordered the test didn't react to it. I trust him so that's why I didn't think it was significant - and perhaps it isn't - but if there's a chance that a Growth Hormone Deficiency would explain some of my symptoms that would be such great news.

I will ask about it when I go to the endocrinologist in about a month. If I find something out I'll try to update the thread. Thank you!

 

[Shanti1]

As Hip mentioned, the insulin tolerance test (ITT) is the gold standard (lowered blood sugar causes GH release). From what I understand it is a terrible test to go through.

I pulled up some notes I had on GH testing from a presentation called "Obtaining Proper Growth Hormone Laboratory Levels" by Dan Purser MD. These are the points he made that may be helpful:

• ITT is the gold standard, but it is a 5 hour test, somewhat dangerous, and brutal to put patients through. However, it is the one insurance is most likely to accept if you are trying to get coverage for treatment.
• GH is too unreliable to use with its peaks, drops, and short half-life
• IGF-1 can be reliable if the proper prep is done:
  • No exercise or sex the day of or before
  • No stressful events the few days prior
  • No stimulating medications 3 days prior
  • Do a morning draw
  • 24-72 hour water fast prior

The last point on the list, the 24-72 hour water fast seems not feasible for most pwME. He did mention that certain foods, specifically proteins and nuts, increase GH more than others, so maybe just a diet low in those foods and an overnight fast would be sufficient. Also, fasting increases GH too, but he didn't go into that.

Here are some slides with additional info:





Your level of 0.07 for GH does seem REALLY low, even given the volitility of the marker, but I don't know if it can drop that low as a normal course.

 

[GlassCannonLife]

I actually read a book a few months ago that was written by leaders in GHRP/GHRH research. They proposed that a GHRP-6 induction test for GH is more clinically useful than current methods (eg the ITT) as it doesn't cause any off-target effects, and can be more specific and reliable.

I'd have to check the book for more specifics than that though as that's all I presently recall.

I'm not sure if this is generally accessible though, as they were suggesting it from a test optimisation perspective rather than implying it was an existing option.

 

[GlassCannonLife]

I tried to check the book but it is too hard to search for it considering how often they mention GHRPs and GH deficiency.. In case anyone is interested, it is called

"Growth Hormone Secretagogues - Basic Findings and Clinical Implications", 1999, by E. Ghigo, M. Boghen, F. F. Casanueva, and C. Dieguez.

It is a bit old, so perhaps their idea of replacing the ITT was not viable. I did see that it is actually a GHRH + GHRP-6 stimulation test (not GHRP-6 alone), and is currently used clinically, but not in preference to the ITT. I originally read the book as I was trying to determine which secretagogue would be best to take, as there is a lot of bro-science around on the internet about GHRPs/GHRHs.

This paper from 2021 actually discusses the tests briefly (mainly in the context of issues with sufficient response in obesity - something to keep in mind for anyone getting tested). For example:

The insulin tolerance test (ITT) is the test of reference for the diagnosis of adult GHD. At the same time, GH-releasing hormone (GHRH), in combination with arginine (ARG) or GH-releasing peptide-6 (GHRP-6), is recognized as being equally reliable [1, 8, 9].

And

The lack of GH response to GHRH + ARG was assumed as the gold standard for the diagnosis of GHD. Thus, as per the GHD diagnosis guideline [1], GHD was defined by using the BMI cut-offs (i.e., a GH peak of ≤11.0, ≤8.0, and ≤4.0 µg/L in lean, overweight, and obese subjects, respectively) [20].

I feel like none of this is really helpful of me to post now that I've read it, but here it is nonetheless lol.

 

[space8]

@Shanti1 and @GlassCannonLife, thank you so much for contributing to the thread!

I’ve read up on the ITT and it seems uncomfortable. I have episodes of hypoglycemia a couple of times a year, so I know how it feels when your blood sugar is low. Mine is about 3.0 mmol/L when having a hypoglycemic episode. I’m not sure how low they allow your blood sugar to go, but if it’s lower than that I can imagine it being very taxing.

Thanks for all the info on the testing process, Shanti! And thank you GlassCannonLife for bringing attention to the GHRH + GHRP-6 stimulation test.

Though, other than the one low GH result, I don’t know if I have an overly strong case for suspecting a GH deficiency other than recognizing most of the symptoms (but they are quite unspecific and would fit for other conditions as well, including ME/CFS). So I wonder if I’d have a case for ITT testing. Seems like they’d be reluctant to perform it without strong suspicions of GHD. The only other thing that would point to it is that I have very high cholesterol, but that could be due to other causes as well. I have something wrong with my bile acid synthesis so that would seem like a more plausible culprit.

I however found something interesting about GH secretion that I thought I could share. One article I read said GH pulses in women occur predominantly during the daytime. But I have not read that from any other source. All other sources say GH is secreted during your sleep.

”In men, approximately 70% of the GH pulses during sleep coincide with slow-wave sleep. The GH pulse is generally the largest and often the only pulse observed over a 24-h period. In women, in contrast to the men, GH pulses occur predominantly during daytime contributing to the greater part of the 24-h release of GH. ”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3183535/#ref20

If that’s true my value of 0.07 does indeed sound low, since you’d expect perhaps higher levels in the morning/daytime in women? I’m uncertain, perhaps it doesn’t work like that at all. Or it doesn’t matter if release occurs during daytime/nighttime since you’d have to time a pulse either way.
______________________________

I also found this table over serum IGF-1 reference ranges in women after age group. I was 25 when my IGF-1 was tested which would make me just barely fall into the 25-29 age bracket. The median was 239 (277 for 20–24-year old’s). I was at 167. That seems normal, I think? 1 SD below the mean but still normal.

I’m pretty short, about 5’1. Not sure if that is significant, since that would mean that I’ve had a deficiency in childhood as well, thus not making it an adult growth hormone deficiency, but something I’ve carried on from childhood if so.

Well, my IGF-1 seems normal in any case so I think it would be difficult to convince a doctor that there would be a need for the ITT. But I am still unsure in which cases they’d go forward with an ITT when IGF-1 generally (even though having some diagnostic value when being very low) can’t be used to exclude the condition. I'm rambling a bit! It would just be really neat to be able to progress in my understanding of what my body is up to (which rarely is something good).

Thank you everyone again for the input!

 

[GlassCannonLife]

@Shanti1 and @GlassCannonLife, thank you so much for contributing to the thread!

I’ve read up on the ITT and it seems uncomfortable. I have episodes of hypoglycemia a couple of times a year, so I know how it feels when your blood sugar is low. Mine is about 3.0 mmol/L when having a hypoglycemic episode. I’m not sure how low they allow your blood sugar to go, but if it’s lower than that I can imagine it being very taxing.

Thanks for all the info on the testing process, Shanti! And thank you GlassCannonLife for bringing attention to the GHRH + GHRP-6 stimulation test.

Though, other than the one low GH result, I don’t know if I have an overly strong case for suspecting a GH deficiency other than recognizing most of the symptoms (but they are quite unspecific and would fit for other conditions as well, including ME/CFS). So I wonder if I’d have a case for ITT testing. Seems like they’d be reluctant to perform it without strong suspicions of GHD. The only other thing that would point to it is that I have very high cholesterol, but that could be due to other causes as well. I have something wrong with my bile acid synthesis so that would seem like a more plausible culprit.

I however found something interesting about GH secretion that I thought I could share. One article I read said GH pulses in women occur predominantly during the daytime. But I have not read that from any other source. All other sources say GH is secreted during your sleep.

”In men, approximately 70% of the GH pulses during sleep coincide with slow-wave sleep. The GH pulse is generally the largest and often the only pulse observed over a 24-h period. In women, in contrast to the men, GH pulses occur predominantly during daytime contributing to the greater part of the 24-h release of GH. ”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3183535/#ref20

If that’s true my value of 0.07 does indeed sound low, since you’d expect perhaps higher levels in the morning/daytime in women? I’m uncertain, perhaps it doesn’t work like that at all. Or it doesn’t matter if release occurs during daytime/nighttime since you’d have to time a pulse either way.
______________________________

I also found this table over serum IGF-1 reference ranges in women after age group. I was 25 when my IGF-1 was tested which would make me just barely fall into the 25-29 age bracket. The median was 239 (277 for 20–24-year old’s). I was at 167. That seems normal, I think? 1 SD below the mean but still normal.

View attachment 45806

I’m pretty short, about 5’1. Not sure if that is significant, since that would mean that I’ve had a deficiency in childhood as well, thus not making it an adult growth hormone deficiency, but something I’ve carried on from childhood if so.

Well, my IGF-1 seems normal in any case so I think it would be difficult to convince a doctor that there would be a need for the ITT. But I am still unsure in which cases they’d go forward with an ITT when IGF-1 generally (even though having some diagnostic value when being very low) can’t be used to exclude the condition. I'm rambling a bit! It would just be really neat to be able to progress in my understanding of what my body is up to (which rarely is something good).

Thank you everyone again for the input!

You could explain that your condition could actually be caused by GH deficiency and see if you can get a stimulation test that way? Your IGF being normal makes it seem unlikely, but I do recall reading somewhere that IGF-1 is not a completely reliable proxy for GH levels and you can still have deficiency in the presence of normal IGF-1 levels. I really should immediately make notes and save the source when I read these things as I can't remember where I read this.. If your doctor is well educated then they may be of more help but that is unlikely to be the case in my experience haha..

Regarding discomfort, yes the ITT would be much less comfortable than either of the the GHRH + ARG or GHRH + GHRP-6 tests, which I believe aren't uncomfortable at all.

You could do a "home-brew" version of the GHRH + GHRP-6 test yourself, ie buy the peptides (getting mod-GRF as the GHRH should be good enough I believe?), check the administration, dosage, and blood draw protocol for the test, and then pin them at the right time before you get your blood drawn to check GH levels (from memory it's around 30 min before, you'd best check though if you want to do this).

 

[Shanti1]

@space8
I found the same, women tend to have more peaks of GH during the day than men, They both have a peak at night. But, as you can see from the image, women can still drop quite low between their daily peeks.


Clinical Neuroendocrinology textbook: Cambridge University Text

Here in the US an endocrinologist would be best for diagnosing GH deficiency, but a Functional Medicine doctor or "Antiaging Specialist" could also do it and would be more likely to use optimal ranges instead of ranges for frank deficiency when considering replacement or the use of secretagogues (substances that stimulate GH release). Not sure if you have that option where you are.

 

[space8]

@GlassCannonLife, thank you! That’s true, all sources I’ve read hitherto say that IGF-1 is not a reliable marker for excluding GHD. This one e.g.:

Having normal levels of IGF1 and IGFBP-3 does not exclude a diagnosis of GHD in adults (9, 11–13). Because of this observation, the perceived role of IGF1 estimation in the diagnosis of adult GHD has been confusing and contentious. Indeed, the regulation of IGF1 secretion in adults is complex and is not solely dependent on GH status. A considerable overlap exists for IGF1 levels between normal subjects and those with GHD (12, 14–17). This overlap remains apparent even among patients with the most severe degree of GHD identified by provocative tests of GH secretion or the number of additional pituitary hormone deficits (17). Therefore, although IGF1 levels may be reduced in patients with GHD, IGF1 has not widely been viewed as a reliable marker for the diagnosis of GHD. However, IGF1 can be of some diagnostic assistance if levels are below the age-adjusted normal range and if factors known to lower IGF1 levels, such as liver disease (18) and starvation (19), are taken into consideration. [European Journal of Endocrinology (2009)]

__

Here’s another a study looking at the diagnostic accuracy of insulin-like growth factor-1 (IGF-1) for screening growth hormone deficiency (GHD) in children, in which they concluded that IGF-1 level had poor diagnostic accuracy as a screening test for GHD.

https://www.nature.com/articles/s41598-021-95632-0

I also read up a bit more on the GHRH-Arginin test and it seems like it’s being performed in my country alongside the ITT test. Or rather, performed if there are contraindications for the ITT, so that was interesting to learn!
__

@Shanti1, that graph was very useful in understanding the gender difference in GH secretion. Thank you for posting! It seems like it would be more difficult to time a point in the day in which GH was close to zero than it would be catching levels around 1-3 in women. That would mean that my test either conveniently timed one of the three close to zero dips in GH release before noon or that my value is too low.

I wanted to calculate the probability for timing a zero dip in pre-noon GH-secretion in women based off that graph but realized I’m just terrible at math/statistics, so I quickly changed my mind.

Functional Medicine doctors would unfortunately not be able to prescribe any medication in my country. They can probably do supplements, but not much more. I've tried some functional medicine in the past but has been quite disappointed in what they can achieve. I've gotten far more help by the regular medical system from the few good doctors I've met.

Getting to try HGH injections would be interesting though. It’s still a long shot. My cholesterol and other symptoms might have nothing to do with GH at all. Though, considering I have couple of previous biomarkers to go off (liver/bile and hormone related) I’m just set on there being an overarching explanation for my symptoms, so I have been reviewing some old test results and is trying to puzzle the pieces together. This might be a side-track, but you never know.

Thank you so much both (or all three) of you for helping!

 

[Shanti1]

This might be a side-track, but you never know.

My policy with my own ME/CFS is "leave no stone unturned"

 

[space8]

My policy with my own ME/CFS is "leave no stone unturned"

That's a good policy! I just wish it would lead to some concrete answers once in a while I've managed to achieve some things by being persistent in the past though but the process is always slow.

I'll carefully mention the GH thing at my upcoming doctors appointment and see where it goes. I'm already seeing the doctor shrugging it off in my mind's eye, but if they don't think GH is an issue in my case I just have to believe that. They are the professionals after all even though I've had several instances in which doctors have missed or overlooked things.

Yes ... I'll try. We'll see how it's received. If I find something out I'll update everyone about it! Thanks again for all the help and suggestions!

 

[GlassCannonLife]

That's a good policy! I just wish it would lead to some concrete answers once in a while I've managed to achieve some things by being persistent in the past though but the process is always slow.

I'll carefully mention the GH thing at my upcoming doctors appointment and see where it goes. I'm already seeing the doctor shrugging it off in my mind's eye, but if they don't think GH is an issue in my case I just have to believe that. They are the professionals after all even though I've had several instances in which doctors have missed or overlooked things.

Yes ... I'll try. We'll see how it's received. If I find something out I'll update everyone about it! Thanks again for all the help and suggestions!

Good luck! You can always buy some black market GH and try medicate yourself, and see if it helps. I believe @mitoMAN did that for a few months.

 

[Jpac]

Hi there!

This might be a long shot, but I was going through some old lab results of mine and happened to see that my GH and IGF-1 had been tested at one point. My IGF-1 seemed to be within the reference range (in the middle somewhat on the lower spectrum).

Though I looked at my GH result and saw it was 0.07 µg/L. I know a single GH test can't be used to diagnose a Growth Hormone deficiency (but neither can a normal IGF-1 exclude it as far as I've understood), but that number seemed a little low to me. There were no reference range since GH secretion is pulsatile.

I read that single values above 3 µg/L could rule out GHD, but do you guys think this could be something to look into or am I grasping at straws? Perhaps GH values close to zero are expected or even desirable. Or perhaps it means nothing due to the pulsatile nature of GH. I know very little about it. I just thought I'd check in.

I'm going to an endocrinologist soon for an unrelated matter and thought I might as well ask about it, but I'm not sure I want to bring it up if it's a completely normal value! What would you say?

My IGF-1 has always been unusually high after being diagnosed. I figured it was my body trying to compensate for whatever was happening

 

[space8]

My IGF-1 has always been unusually high after being diagnosed. I figured it was my body trying to compensate for whatever was happening

Is your IGF-1 off the charts high? If so it's sometimes indicative of Acromegaly. https://www.mayoclinic.org/diseases-conditions/acromegaly/diagnosis-treatment/drc-20351226

When I've read up on Growth Hormone Deficiency after posting this I also encountered a lot of info on that condition and as far as I've understood IGF-1 that's way below the lower reference range is enough to strongly suspect GHD and an IGF-1 above the higher reference range enough to strongly suspect Acromegaly.

Have you excluded it?

 

[Crux]

My IGF-1 has always been unusually high after being diagnosed. I figured it was my body trying to compensate for whatever was happening

There are other causes for elevated IGF-1 :

https://www.healthline.com/health/igf-diabetes#testing

If your test results show higher or lower levels than the normal range, there could be several explanations, including:

• low thyroid hormone levels, or hypothyroidism
• liver disease
• diabetes that isn’t well-controlled

I happened upon an easy remedy for elevated IGF-1, Zinc, which is involved with regulation of IGF-1 and GH.

A reasonable amount of zinc reduced my IGF-1 from 404 to 239 ng/ml in about 9 mths. The growth hormone was 3.42 ng/ml. I doubt that it would be this easy for everyone, but it would be a good test or trial.

 

[space8]

If your test results show higher or lower levels than the normal range, there could be several explanations, including:

• low thyroid hormone levels, or hypothyroidism
• liver disease
• diabetes that isn’t well-controlled

I happened upon an easy remedy for elevated IGF-1, Zinc, which is involved with regulation of IGF-1 and GH.

A reasonable amount of zinc reduced my IGF-1 from 404 to 239 ng/ml in about 9 mths. The growth hormone was 3.42 ng/ml. I doubt that it would be this easy for everyone, but it would be a good test or trial.

As far as I've understood, hypothyroidism and liver disease are generally related to lower IGF-1 values while diabetes/insulin resistance can cause both lower and higher values of IGF-1! Which can be good to know!

The connection to zinc is interesting. I haven't read that before!