Low levels of estrogen stimulate a growth spurt during puberty, while high levels accelerate the fusion of the growth plates.
The enzyme aromatase is responsible for high estrogen levels, as it converts testosterone into estrogen.
The treatment method suggests suppressing the action of aromatase with inhibitors, thereby extending the lifespan of growth plates.
The two most popular drugs for this purpose are anastrozole and letrozole.
Studies show that after 2 years of treatment with letrozole, bone age increases by 1.24 years, while in the placebo group, it increases by 2.05 years. As a result, the group with the inhibitor achieves a final height that is 6 cm taller.
relatively short-term treatment with letrozole may increase final adult height much like long-term treatment with growth hormone1
This treatment is not prescribed for girls because it increases testosterone levels too much, leading to problems with the reproductive system and bones.2
Overall, testosterone stimulates a growth spurt during adolescence, which is why this therapy is used in males, including for idiopathic short stature and delayed puberty.
boys will achieve an adult height closer to their genetic growth potential if the estrogen action is inhibited.3
Practical nuances in cases of short stature
- Only for males.
- Start treatment during early or mid-puberty (Tanner stage 2-3). When the treatment goes before the onset of sexual maturation, we have little endogenous testosterone, and a greater risk of underdeveloped spine and bones.
- The course duration should not exceed 1-2 years. During this time, there are fewer side effects observed.
- The studies used a daily dose of 2.5 mg of letrozole or 1 mg of anastrozole.
- Check bone and spine density once a year. Estrogen helps accumulate minerals in bones, and blocking its effects may prevent optimal bone mass gain. Treatment is not conducted if a person has inadequate mineral density.
- Use calcium and vitamin D supplements.
- Other possible issues include thrombus formation (check hemoglobin and hematocrit levels), decreased high-density lipoprotein (HDL) cholesterol, and memory problems.
- Choose anastrozole, as it is weaker than letrozole. A less potent aromatase blockade may have a lesser impact on testosterone elevation and potentially have a gentler effect on bone health.
- The medication is combined with growth hormone therapy for growth delay and testosterone for delayed sexual maturation.
Consult a specialist to maximize the benefits of aromatase inhibitors and minimize side effects.