Most people know at least surface level stuff about the hormone testosterone. If you’re involved in the fitness industry, you’ve heard of all kinds of supplements that claim to boost this hormone. Statements like that can make a person’s mouth water…When I was in college a friend of mine took a pre-workout called Bullnox. Shit was insane…Changed your mood and everything. We were convinced it had magic powers. The pump was also real nice.
This post is NOT about specific testosterone supplements, however. This is about the mineral zinc’s role in your testosterone levels. I’ve heard zinc is important to help balance out your normal levels of testosterone, but can it increase your normal levels as well? Let’s find out!
Some quick information before we get started:
Doctors most commonly measure testosterone levels in a unit known as nanograms per deciliter (ng/dl).
Normal testosterone levels in men and women (Adults)
|Age||Male (in ng/dl)||Female (in ng/dl)|
|17 to 18 years||300-1,200||20-75|
|19 years and older||240-950||8-60|
You may know your total testosterone levels, but they don’t tell you everything. It can be divided into three categories:
- Tightly bound testosterone. About two-thirds of the testosterone in your blood is bound to sex hormone binding globulin (SHBG). Your body can’t use it.
- Loosely bound testosterone. About one-third of the testosterone in your blood is bound to albumin. Your body CAN use it, but with some effort.
- Free testosterone. A small percentage of the testosterone in your blood (1–4%, as a rule) just floats around freely. Your body can readily use it, and the enzyme 5-alpha-reductase can convert it to dihydrotestosterone, a very potent androgen.
Together, your loosely-bound and free testosterone compose your bioavailable testosterone, which has a greater impact on your health than your total testosterone.
Okay, now some quick information on Zinc!
An essential mineral used in antioxidant enzymes, brain function, and immune system health. It also plays a role in regulating optimal testosterone levels. 40mg per day is the tolerable upper daily limits of zinc. You need to be careful though. Side effects may occur if you supplement with zinc as well as eat a diet high in zinc. Always be careful when supplementing with minerals. They are not like B-vitamins which can be removed through urination.
So, what do the studies say?
One study out of Pub Med examined the relationship between cellular zinc concentrations and serum testosterone cross-sectionally in 40 normal men, 20 to 80 y of age. They placed groups in a zinc deficient diet 3-6 months as well as groups of healthy older individuals with zinc supplementation. They found dietary zinc restriction in normal young men was associated with a significant decrease in serum testosterone concentrations after 20 weeks of zinc restriction. They also found Zinc supplementation of marginally zinc-deficient normal elderly men for six months resulted in an increase in serum testosterone. Thus, concluding zinc plays a role in testosterone levels in both deficient and sufficient zinc leveled people.
This just goes to show that a lack of zinc will lower testosterone. It also shows that if you’re of an elderly age, zinc will increase testosterone levels to optimal level.
BUT WILL IT INCREASE TESTOSTERONE IN HEALTHY ADULTS???
One study tested elite athletes who were wrestlers age 17-21. They knew testosterone production drops briefly after total exhaustion during a workout. Though the drop is not permanent, it is still beneficial to keep levels elevated for maximum benefit. They supplemented the athletes with 5mg of zinc sulfate for four weeks. Then they measured resting testosterone levels and levels after exercise to total exhaustion. What they found was that “exhaustion exercise led to a significant inhibition of both thyroid hormones and testosterone concentrations, but that 4-week zinc supplementation prevented this inhibition in wrestlers.”
The supplementation prevented the dip in testosterone, but did not significantly increase total levels.
So, can zinc supplementation increase total testosterone levels in healthy adults? Based on what I’ve seen no, it will not.
It will ensure that your testosterone levels are at their normal optimal level. It will also make sure they stay elevated after intense exercise.
Some things to note:
I was not able to find a study that took healthy adults who had sufficient zinc from their diet, and proved it in fact raised their total levels of testosterone. It would be a hard study to implement and there could be a lot of obstacles to go through to prove its effectiveness.
My recommendation? Check your diet, eat zinc dense foods, check your testosterone levels, and ask your doctor if you could benefit from supplementation.