I wanted to show the readers in this post something which I have been finding a lot recently, which is that different medical sources seem to say the exact opposite thing in their results. I was doing research on BMPs for another post and there was contradictory information on which BMPs have the highest chondroinductive potential.

So for this post, I wanted to focus on the compound Tamoxifen. Tamoxifen is what is known as an aromatase inhibitor, where it is supposed to prevent androgens aka testosterone in the body from turning into estrogen. 

So by that logic, since it is preventing estrogen from being produced, it should help in increasing the length of time for growth from preventing growth plates from fusing completely.

There is sources that support this idea like from old Height Increase forums in threads like Real advice from an endocrinologist…

“…Anti-estrogen, or aromatase blockers, are available widely and might not require a prescription. They should be safe, but given that they deal with the brain, if you experience and neurologic effects like uncontrollable shaking of your hand, stop treatment and seek professional advice. Examples of anti-estrogen can be Letrivole, Tamoxifen and many more.”

Other sources like from the article Tamoxifen May Help Short Boys Grow Taller

“…tamoxifen, which is usually used for the treatment of breast cancer, decreases the rate of skeletal maturation in boys giving them time to attain higher final body height. These research findings were reported in the in a recent issue of the medical journal Pediatrics.”

The referenced study is The Use of Tamoxifen to Improve Height Potential in Short Pubertal Boys. It would seem that many of the other websites that are saying that Tamoxifen can help increase height all reference this one study, which for me is slightly troubling.

The main thing to note from the real source is that the few boys tested on were almost 15 years old and on average had tamoxifen administered for a littler over 2 years.

THE OPPOSITE SIDE

Interestingly Tyler wrote about this factor in the post Grow Tall With Tamoxifen where he realizes that there seems to be more evidence showing that Tamoxifen is bad for longitudinal growth.

Not only that, Hakker posted years ago in the bodybuilding forum this…

“Avoid tamoxifen (sold as “Nolvadex”). Bodybuilders on steroid cycles often use tamoxifen because it interferes with the estrogen receptor; that way, they don’t get man boobs. Some may take tamoxifen for its anti-estrogen qualities to keep their growth plates open. Don’t. In several studies, ironically, tamoxifen has actually caused irreversible death of growth plate cells, a precursor to the fusion of the growth plates. In some instances, tamoxifen has been given to end the growth of very tall girls. Tamoxifen also greatly stunts growth hormone secretion and IGF-1 production. Tamoxifen is an anti-breast cancer drug. Not a bodybuilding drug. Bodybuilding and anti-estrogen is an off-label use of tamoxifen. Lowered GH and IGF-1 is good for breast cancer, but bad for growth. Take home lesson: Avoid tamoxifen or Nolvadex.”

This concurs with two studies I have found on PubMed point at that fact…

1. Tamoxifen impairs both longitudinal and cortical bone growth in young male rats.
2. Tamoxifen induces permanent growth arrest through selective induction of apoptosis in growth plate chondrocytes in cultured rat metatarsal bones.

Another source I wanted to cite is “Precocious puberty and statural growth”

“…From the Discussion Section..Tamoxifen, a selective estrogen receptor modulator, has also been used and a recent report of a 1 year treatment shows a decreased frequency of bleeding episodes (from 3.4 to 1.2 per year in average), a decrease of growth velocity (–1.8 ± 3.0 SD) and a decrease of bone age maturation (ΔBA/ΔCA: –0.5 ± 1.0). Of note, nine of the 25 patients in this study had failed on aromatase inhibitors and were successfully treated with tamoxifen. In any case, no data are available on the long‐term effects of aromatase inhibitors or tamoxifen on height in McCune–Albright syndrome.”

Final Analysis:

It would seem that Tamoxifen seem to have two functions towards height. It causes chondrocytes to die out at a faster rate but somehow it also manages to slow down bone maturity. It is very confusing. From the first study cited above…

“…elevated chondrocyte proliferation and apoptosis, as well as decreases in the number of hypertrophic chondrocytes and in the size of terminal hypertrophic chondrocytes”

I am left to wonder whether the way tamoxifen really works is to just lead the chondrocytes to proliferate at a higher rate but don’t allow the chondrocytes to go through full hypertrophy, and then killing the cells off. This explains the growth arrest but not how it is able to slow down growth plate maturity. Very strange, and still confused at the writing and posting of this article.

Side Note: Hakker on the same bodybuilding forum thread notes this about the phytoestrogen in soy products which is the same idea I proposed a a very recent post “Phytoestrogens Found In Soy Based Foods May Explain Why Vegetarians and Asian Ethnicities Have Been Historically Shorter (Very Important!)”

Avoid soy products – Not only do they contain potent phytoestrogens that can mimic estrogen’s effects on the growth plates, but the same soy phytoestrogens have been shown to block IGF-1 signaling. Soy is bad for growth at both ends: at increasing IGF-1 and at lowering estrogen. Read ingredient labels; avoid anything that lists soy protein as a major ingredient. Soy sauce does not contain much at all of these chemicals. (Hakker)

Avoid broad beans, also known as fava beans – It contains a potent phytoestrogen (plant-based compound with effects in the body similar to estrogen) that has the ability to activate estrogen receptors. The growth plate is full of estrogen receptors. In the presence of its activation, it may begin to turn into hard bone and end growth completely. (You might even say that broad beans will turn you into a broad.) Those who red the scam book Grow Taller 4 Idiots (seriously for idiots) know that it recommends broad beans because it contains a growth hormone secreatogue, L-DOPA. Oral ingestion of L-DOPA does increase growth hormone, but not significantly in doses contained in broad beans. To achieve a significant growth hormone increase with L-DOPA, one would have to obtain purified L-DOPA from plants, which is usually so expensive that I didn’t bother to put it on the list, or get synthetic L-DOPA, which can only be obtained with a prescription. Also note: The same phytoestrogens in broad beans are found in soybeans, although the issue of phytoestrogens in soy is sure to stir up debate. (Hakker)

Just something to consider for myself when I reach the same conclusion as the research done by Hakker and the gang at Grow Tall Forum years back. Sometimes I do wish I did not have to reinvent the wheel in terms of rediscovering already studied and concluded points and get some of the already done research form the now dead website. Oh well.