Understanding SHBG And Free Testosterone
Total testosterone and free testosterone are not the same thing, and the difference matters for understanding how ingredients like Tongkat Ali, Nettle Leaf and Boron are meant to work.
Here is a plain-language explanation of SHBG and why it's central to HorseWood's positioning.
What SHBG actually is
Sex hormone-binding globulin (SHBG) is a protein produced mainly by the liver that binds to testosterone in the bloodstream. Testosterone bound to SHBG is largely biologically inactive — it can't interact with tissue receptors the way free (unbound) testosterone can.
Why SHBG rises with age
SHBG levels tend to increase with age, meaning a larger share of a man's total testosterone becomes bound and unavailable, even if total testosterone levels look normal on a standard lab panel. This is one reason some men experience "low-T symptoms" despite normal-range total testosterone results.
How certain compounds are thought to help
Some plant compounds, including those in Nettle Leaf, are studied for their ability to bind to SHBG themselves, competitively displacing testosterone and increasing the free, usable fraction. Boron is separately studied for its association with lower SHBG and higher free testosterone in small clinical trials.
Our bottom line
Understanding SHBG helps set honest expectations: this is about optimizing what's already available, not manufacturing new testosterone from nothing. See the full ingredient breakdown for specifics.
