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Low Bone Density on TRT

Hi all,

I have been on TRT since 2015 due to low T levels. At the same period of testing then I also did a bone density scan which revealed low bone density, which was one of the main reasons motivating me to start TRT as I did not have any effects of low T. I did not check Vitamin D levels at that time but I suspect that it might have been borderline low for all my life.

A couple of weeks ago I re-did the bone density scan, which showed a further bone loss. The density of L4 vertebrae was at -2.9 which was even lower than pre-TRT. I have been taking around 3000 IU of Vitamin D plus 800 mg Calcium and 400 mg Magnesium daily for the duration of TRT. Last blood test shows the Testosterone level at 22.9 nmol/mL (range 10 - 30). and Vitamin D still on the lower side at 33 (range 30 - 100). I’m adding a 10,000 IU Vitamin D + high K2 dose to my daily supplements as from next week.

I am using 1000mg of Testosterone Undecanoate (Nebido) every 10 weeks. The previous test result was taken at the 9th week so average T levels would be somewhat higher. I am now reducing the injection period to 8 weeks to maintain slightly higher levels. I also take 500 mg of Anastrazole bi-weekly. E2 level was at 18 pg/mL.

What could be causing this loss, since TRT increased T plus more Vitamin D, Calcium, Magnesium plus many other supplements while also lifting regularly?
I am thinking that lowish Vitamin D might be a culprit, but also suspecting that low E2 is contributing. Pre-TRT I used to have average E2 levels around 32 pg/mL. Apart from this, all other markers have improved.

Thanks for any feedback.

Did the doctor that performed the bone density test not tell you you have osteoporosis?
The bone scan range only goes to 4 so 2.9 is alot of loss.
You need to do more than take OTC supplements. Have you ever heard of Alendronate?

Thx for the reply. Yes the doctor explained that bone loss was serious. I asked him about bisphosphonates - he said that its a possibility, but used as a last resort due to side effects. He suggested and prescribed the high Vitamin D dose. I will also be reducing the AI dose to allow more E2 to help mineralization.

Is that anastrozole dose correct?

I meant 500 mcg bi-weekly. Half a tablet Monday and Thursdays. I might split this further to lower the dose.

I think I would drop that completely. Has your parathyroid function been evaluated?

I suggested checking this with the Doc but since my Serum Calcium levels were always within range he dismissed it.
I also obtained some Alfacalcidol and was thinking of using them but the Doc did not recommend it since they are meant for patients with renal issues and they can alter other blood test results.

OK, then I would definitely stop anastrozole. Other causes of osteoporosis include smoking, gastrointestinal disorders, some medications, especially glucocorticosteriods, alcohol consumption, various rare diseases and, of course, hypogonadism. How long do you think you could have had low testosterone? Since yours is progressing despite everything and assuming none of the usual factors are present, I think you have to look at E2.

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Agreed on E2, that is my primary suspect which I’ll see to, by stopping the AI.
I don’t take any other medications, only dietary supplements which includes protein powder and a healthy diet.
Apart from this I don’t smoke or drink or have any other conditions. I think I had low testosterone for the duration of my lifetime since I was already tested during teenage years and it was already low (I’m 33 now). This lifelong low T & Vitamin D did a lot of damage and it takes long to rebuild.
One other thing is that I always have an elevated TSH, usually between 3 - 4, but T3/T4 are OK. Can this affect bones in some way?

Would a 24 hour urinary Calcium test be worth it in this case?


You know what, this is serious enough to make me want to cover all bases. As you don’t have any other obvious risk factors, I think I would go ahead and do that. Also, parathyroid hormone, calcitonin, unless your doctor has already. Assume they just have serum calcium.

What are your fT3 and fT4 numbers? Reverse T3? Chronic hyperthyroidism can lead to osteoporosis. Does not seem this would apply to you.

I have had Calcium, Phosphate and Magenisum checked many times and these were all fine. I tried to get the PTH, Calcitonin but our local lab does not process these tests and since the other results were ok they were declined.

Thyroid results (typical):

Thyroid Stimulating Hormone (Centaur) 4.328 0.3 - 3.0 micIU/mL
Free T4 (Centaur) 13.90 11 - 18 pmol/L
Free T3 (Centaur) 5.4 3.5 - 6.5 pmol/L
Anti-Thyroid Peroxidase Antibody (Euroimmun) <10.0 0.0 - 50.0 IU/ml


Without getting into a long drawn out thing over it, make sure your K2 is MK-4 and not MK-7.

Seems mine is MK-9 and I’m taking 300 mcg daily…

How old are you. Second dropping the AI. Low e2 causes bone loss.

I am 33 years old. Hope dropping the AI does not cause significant side effects.

Dude, Osteoprosis is a serious side effect. Far worse than a small amount of high E2 can cause.

You can always lower dose, or try natural methods. I had my E2 in that range for a long time, about a year, and I had horrible knee pain, couldn’t squat, jump or run for almost 2 years. IM just barely coming around.

I still have problems accidentally lowering my e2. It sucks. I hope I don’t have any of those issues.

So are you saying you already had osteoporosis BEFORE you started the arimidex?

Do you have any idea why:?

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Hope you keep well now…

I had low bone density already, but it was not low as it is now, but then again it might have been due to the lack of sufficient Testosterone and Vitamin D levels which was basically all my life.

Just as an FYI, I supplement with 10,000iu a day vitamin D a day for a 65 reading.


So you don’t know why you had low density to begin with? How long do you suspect you had low T? were you good in your 20’s?

that gives me some relief, but I think im gonna be back on the vitamin D today. @NH_Watts Cue my estrogen to tank. LMAO… Getting it checked first to see if its even needed.


@anon10035199 I heard an aggressive night of dihydrogen monoxide once tanked your E2. Care to comment? :laughing:

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