Why Most People Are Taking Vitamin D Wrong

Vitamin D was one of the top five sellers in my store. Consistently. Every month, without fail.

And yet — I can’t tell you how many customers came back frustrated, saying their doctor just told them their Vitamin D levels were still low after months of supplementing. They weren’t skipping doses. They weren’t buying bad products. They were doing something that seems completely logical but quietly kills absorption: taking it wrong.

This happened so often that I started asking every Vitamin D customer the same two questions: what time of day are you taking it, and what are you eating when you take it?

The answers explained everything.

The Most Common Mistakes

How to Actually Take Vitamin D Correctly

After many years of these conversations, here’s the full protocol I recommended more than any other:

Should You Take K2 With D3?

I got this question constantly toward the end of my store’s run, as K2 started getting more attention in the supplement world. Here’s my honest take on it.

The logic is sound: Vitamin D increases calcium absorption from your gut. More calcium in circulation is great for bones — but calcium also has a tendency to deposit in soft tissues and arteries if it isn’t properly directed. Vitamin K2, specifically the MK-7 form, activates proteins that shuttle calcium into bones and teeth and away from arterial walls.

The research isn’t as definitive as the Vitamin D research — this is a newer area and we need more long-term human trials. But the mechanism makes biological sense, the risk of adding K2 to your routine is essentially zero at normal doses, and some of the cardiovascular research on K2 is genuinely compelling.

My personal take: if you’re taking Vitamin D3 at 2,000 IU or above on a regular basis, adding K2 (100 to 200 mcg of MK-7 daily) is a reasonable and low-risk decision. If you’re just taking a standard 1,000 IU dose in a multivitamin, don’t stress about it.

Who Is Most at Risk for Deficiency?

This is something I didn’t see discussed enough in the store, so I want to address it directly.

The groups most likely to be genuinely deficient, not just borderline low, include:

• People who work indoors all day — which is most of us. Your body produces Vitamin D from UVB sunlight exposure on bare skin, and if you’re inside from 8am to 6pm, you’re getting almost none of it regardless of where you live.
• People with darker skin tones. Melanin is a natural sunscreen — it protects against UV damage, which is beneficial, but it also significantly slows Vitamin D synthesis. Studies consistently show higher rates of deficiency in African American, Hispanic, and South Asian populations.
• People over 60. Skin becomes less efficient at synthesizing Vitamin D with age, and the kidneys become less effective at converting it to its active form. Older adults generally need higher doses and benefit most from supplementation.
• People who are overweight or obese. Vitamin D is fat-soluble, which means it gets sequestered in fat tissue and is less available in circulation. Higher body fat essentially pulls Vitamin D out of the bloodstream and stores it where it can’t be used effectively.
• People in northern latitudes — or anywhere with limited sun for several months a year. If you’re living somewhere that gets real winters, you have months where the UVB angle of the sun is insufficient for any meaningful skin synthesis, regardless of how much time you spend outside.

If you fall into any of these categories, supplementation isn’t optional — it’s genuinely important.

A Word on Toxicity

People occasionally ask whether you can take too much Vitamin D. The answer is yes — but the threshold is much higher than most people realize and is essentially impossible to hit through normal supplementation.

Vitamin D toxicity, which causes hypercalcemia (too much calcium in the blood), has been documented at sustained doses of 10,000 IU or more per day over extended periods. At 2,000 to 4,000 IU daily — the range I recommend — you are nowhere near that territory.

The nuance is that individual response varies. Some people are “hyperresponders” who raise their levels quickly on relatively low doses. This is another reason to get tested — it removes the guesswork and tells you exactly where you stand.

Final Thoughts

Vitamin D is one of the supplements I feel most confident recommending because the deficiency is genuinely widespread, the consequences of being chronically low are real — suppressed immunity, low mood, bone health decline, hormonal disruption — and the fix is inexpensive and straightforward.

But only if you take it right.

With fat. In D3 form. At a meaningful dose. Every day.

Get tested, find your baseline, supplement appropriately, and retest in three months. That’s it. No complicated protocol, no expensive products — just fixing the basics that most people are getting wrong.