TacticalBarbell.com

Yep. Zinc is one of those minerals people tend to be extremely cavalier about, not realizing that it can cause irreversible neurotoxicity in some cases. Scary thing is, the doses needed aren't as high as you might think.

Here's a recent study indicating that as little as 60mg a day (total, not just supplemental) can cause changes to the hippocampus and impair learning and memory:

http://journals.plos.org/plosone/articl ... ne.0055384

If you supplement with 30mg, and your multi has an additional 15-30-- that's close to 60mg right there without accounting for the zinc content in your food. Most of us I'm assuming eat high protein, lots of meat, which is choc full of zinc by itself.

Copper plays a role in dopamine synthesis, and iron absorption...both very important for energy.

Supplementing single minerals/vitamins can cause imbalances, even something as innocent as D which people are popping like candy. If you have insufficient vitamin K, excess D can cause arterial calcification. D can also exacerbate magnesium deficiency. Excess magnesium can cause calcium imbalance. It goes on.

I've always been told 20mg/day max with zinc. I've been taking that dose for years no problem

Tyr0331 wrote:I've always been told 20mg/day max with zinc. I've been taking that dose for years no problem

Up to 30mg isn't usually a problem for most. It depends on how much copper you get in your diet, whether you're also taking a multi (does it have copper?) and dietary zinc intake. For example, it's not uncommon for athletes to take a multi along with ZMA. Multi's can contain anywhere from 15-30mg of zinc. Add in 30 from ZMA and you're entering 45-60mg+ a day.