A Butt-Load of Studies

If you printed out every scientific study on vitamin D and taped them all together, end to end, the length of that paper would stretch all the way around Kim Kardashian's fake ass... twice.

Yeah, that's a LOT of studies. And they pretty much all say the same thing: most people have a vitamin D deficiency. Low vitamin D has been linked to a ton of problems:

  • A deficiency can lead to a loss of strength and poor athletic performance.
  • A deficiency can make it more likely that you'll get fat and get type 2 diabetes, cancer, or heart disease.
  • It can make it harder to build muscle.
  • It can wreck a woman's sex drive and ability to have wake-the-neighbors orgasms.
  • A deficiency may even lead to depression and low T.

The list goes on. And that's why most of us supplement with 1000 to 5000 IUs of vitamin D3 per day, especially in the winter. But now a new study says all that supplementing may not be doing us any good if we're deficient in something else: magnesium.

The Science

The research... is pretty damn boring. So I'll bullet point a review published in The Journal of the American Osteopathic Association:

  • Vitamin D can't be metabolized without sufficient magnesium levels.
  • That means a lot of that supplemental D you're taking remains stored and inactive.
  • About 50 percent of Americans aren't even getting the minimal RDA of magnesium: 420mg for people born with penises and 320mg for people born with vaginas. (Gender and sex are SO confusing these days.)
  • People with optimum magnesium levels require less vitamin D.
  • Besides causing your vitamin D supplements to "not work right," that un-metabolized vitamin D can increase your calcium and phosphate levels, and that could lead to vascular calcification, which is not a good thing.
  • In a nutshell, your vitamin D intake may be technically okay, at least if you get a lot of sunshine or supplemental D. It's your magnesium deficiency that could be the real root cause of the problem.

The Solution

Get more magnesium, of course. Now, we could list a whole bunch of foods that contain a good amount of magnesium, but there's a problem. Industrialized agriculture has stripped away a lot of the magnesium in whole foods.

On top of that, lifters and athletes excrete more magnesium than average people (as do people under stress). One tough workout can deplete magnesium levels for up to 18 days. So you'd have to eat a whole bunch of spinach, Swiss chard, and pumpkin seeds to replace it.

So the best source of magnesium is a quality supplement that uses a highly bioavailable form of magnesium. Ideally, it would also have vitamin B6 added to the formula to further enhance uptake and utilization. The top choice is ZMA®. Just take 3 capsules before bed.


As a bonus, ZMA® also provides 30mg zinc, another mineral lifters and athletes are notoriously deficient in.

Related:  Take This to Increase Testosterone by 24%

Related:  Get ZMA® Here


  1. American Osteopathic Association. "Low magnesium levels make vitamin D ineffective: Up to 50 percent of US population is magnesium deficient." ScienceDaily. ScienceDaily, 26 February 2018.