annjason31
Iron
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- Aug 5, 2026
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After some research, I feel like I have a general understanding of letro and why, when thinking of it in a stack, u prob shoudlnt use it and why I won't, kinda based on this study
1. too much E2 nuke
Problem with Letrozole is it nukes E2 the hardest, which does slow bone-age progression but the E2 is still important for bone remodeling/growth, also nukes it below optimal amount to slow down plates
Estradiol is also important for keeping osteoclasts (the cells that break down bone) under control
In a 3-year randomized trial comparing letro vs anastroz in boys, letro caused lower E2, higher test, and slowed bone-age progression more
2. Stronger suppression does not = better height prediction
Despite slow bone age, the same trial didn't find a significant difference in predicted height improvement between the two after treatment, so you can theorize that you're nuking the E2 and making ur bones even weaker than they need to be for optimal height gains
3. Letrozole reduced igf1 more
Important for height and compared with anastrozole, the let group had lower igf-1 and slower growth velocity
So with letro, your e2 is suppressed more, which means ur plates mature slower, but also igf1 decreases, plus growth velocity, and actual growth slows
So the theoretical goal shouldn't be nuke e2 to max, I think it should be reduce it enough to slow bone-age while preserving gh/igf-1singilaing
Why am I running Arimidex
A randomized trial found that adding anastrozole to GH slowed bone-age advancement, increased predicted adult height potential, and maintained normal pubertal progression.
SO Basically,
Arimidex
E2 - down
bone-age speed - down
igf-1 better preserved
growth velocity better preserved
more balanced
pubmed.ncbi.nlm.nih.gov
https://pubmed.ncbi.nlm.nih.gov/18165285/
1. too much E2 nuke
Problem with Letrozole is it nukes E2 the hardest, which does slow bone-age progression but the E2 is still important for bone remodeling/growth, also nukes it below optimal amount to slow down plates
Estradiol is also important for keeping osteoclasts (the cells that break down bone) under control
In a 3-year randomized trial comparing letro vs anastroz in boys, letro caused lower E2, higher test, and slowed bone-age progression more
2. Stronger suppression does not = better height prediction
Despite slow bone age, the same trial didn't find a significant difference in predicted height improvement between the two after treatment, so you can theorize that you're nuking the E2 and making ur bones even weaker than they need to be for optimal height gains
3. Letrozole reduced igf1 more
Important for height and compared with anastrozole, the let group had lower igf-1 and slower growth velocity
So with letro, your e2 is suppressed more, which means ur plates mature slower, but also igf1 decreases, plus growth velocity, and actual growth slows
So the theoretical goal shouldn't be nuke e2 to max, I think it should be reduce it enough to slow bone-age while preserving gh/igf-1singilaing
Why am I running Arimidex
A randomized trial found that adding anastrozole to GH slowed bone-age advancement, increased predicted adult height potential, and maintained normal pubertal progression.
SO Basically,
Arimidex
E2 - down
bone-age speed - down
igf-1 better preserved
growth velocity better preserved
more balanced
Anastrozole vs Letrozole to Augment Height in Pubertal Males With Idiopathic Short Stature: A 3-Year Randomized Trial - PubMed
Letrozole caused greater deviations than anastrozole in hormone levels, growth velocity, and BA advancement, but no group differences in PAH or side effects were found. Change in PAH after 2 to 3 years of treatment was minimal. The efficacy of AI as monotherapy for height augmentation in...
pubmed.ncbi.nlm.nih.gov
