Only 3% of circulating testosterone (T) if not bound to a carrier protein call sex hormone binding globulin (SHBG), and the unbound “free” portion is the active portion. With aging our SHBG tends to increase resulting in less free T. A common pattern in lab testing is to have a pretty good total T level with a low free T level, thus effectively resulting in low T.
By lowering SHBG one can increase the free T level. If total T production is good then this is preferable to supplementing T with a prescription.
Supplements to lower SHBG
- Eat plenty of plants to get plenty of carbohydrates. Include lots of cruciferous vegetables such as broccoli and cauliflower to help metabolize excess estrogen which further lowers SHBG. Excess fat lowers T levels while excess protein doesn’t seem to have much impact. Avoid excess alcohol, caffeine and sugar.
- Supplement with boron 5-10mg/day. Check serum zinc, magnesium and vitamin D as low levels are associated with lower T levels.
- Supplement with DIM to improve estrogen metabolism / elimination which further lowers SHBG