The mechanism for the decline in SHBG during puberty is unclear; it was suggested that decreases in SHBG are partly due to increases in testosterone (51). Considering that it is probably an indirect effect of testosterone on SHBG production, and could be affected by other mediators, the influence of testosterone on SHBG appears to be minimal during early puberty. This appears contrary to the classical postulation that testosterone inhibits SHBG production, which was mainly supported by studies of androgen treatments in males and in human liver cells (6, 14, 15, 49). In addition to the influence of SHBG on total-T, our results of mediation models and Mendelian randomization also indicated a possible—albeit somewhat weaker—positive effect of total-T on SHBG in late puberty and adulthood. Changes in pro- or anti-inflammatory cytokines and alteration in the transcription factors (such as HNF-4α and PPAR-γ) of SHBG gene that occur in obesity could account for the reduction in plasma levels of SHBG (47, 48).
AlphaMD is a telehealth provider specializing in hormone optimization for both men and women. This is part of the reason why both men and women experience hormonal changes as they get older, including reduced free testosterone. As we age, SHBG levels naturally increase. In this article, we’ll break down what causes high SHBG, what it means for your health, and what to consider if your labs show elevated levels. This issue can impact both men and women, often causing symptoms that lead people to explore solutions like testosterone replacement therapy. Body fat percentage, alcohol intake, vitamin D levels, problems with insulin levels or the thyroid, and even your diet. Sometimes SHBG can be high due to hormonal imbalances, aging, and low body health or due to thyroid issues.
These variations can have profound effects on the body’s endocrine system and overall health. Moreover, SHBG levels can be an indicator of metabolic health. The interaction of SHBG with these hormones also has broader health implications.
A few studies indicate that the testosterone derivative estradiol might play an important role in male aggression. The Annals of the New York Academy of Sciences has found that the use of anabolic steroids (which increases testosterone) among teenagers is correlated with increased likelihood of using violence. The rise in testosterone during competition predicted aggression in males, but not in females.
The timing of puberty can be quite varied (45), and most individuals may not have a fully active HPG axis until 17 years of age. The positive correlation between SHBG and total-T emerged at 15 years of age and grew stronger at age 17. Nonetheless, our results also indicate an additional effect of total-T on SHBG in late puberty. With SHBG and total-T in the same model, the relationship between total-T and BMI disappeared, while the SHBG-BMI relationship remained (Table 1C).
Men who produce less testosterone are more likely to be in a relationship or married, and men who produce more testosterone are more likely to divorce. However, the testosterone changes observed do not seem to be maintained as relationships develop over time. There has been speculation that these changes in testosterone result in the temporary reduction of differences in behavior between the sexes. Testosterone may be a treatment for postmenopausal women as long as they are effectively estrogenized.