How Much Vitamin D Should You Take? Probably More Than You Think

Vitamin D is a hot topic, and not just because it's associated with the sun. Really, though, cheesy jokes aside, one major reason everyone is talking about the sunshine vitamin these days is that a whopping 93% of us1 aren't getting enough of it through natural food sources alone—and considering the essential nutrient is vital to immunity, bone health, muscle function, mood, and more,* that's a pretty big problem.

Since we can't rely on food to get our vitamin D to where it needs to be, and trying to score enough of the sunshine vitamin from the actual sun is—ironically—a complicated, caveat-riddled can of worms in and of itself (and a topic for another day), that leaves us with one tried-and-true route to healthy vitamin D status: supplements.*

Vitamin D is classified as a fat-soluble vitamin, but it's unique in that it's also a preprohormone2 (which means it's a precursor to a prohormone, which is a precursor to an active hormone) and a really important one, at that. "There are binding sites for [vitamin D] on nearly every cell in the body," integrative dietitian Whitney Crouch, RDN, CLT, tells mbg. "Vitamin D3 plays a role in calcium absorption and balance, bone mineralization, immune function, cardiovascular health, and more."*

In fact, many experts and an ever-growing body of research agree that you need to keep your levels significantly higher than this to keep your body healthy and feel your best. 

"This is the bare minimum level to avoid issues known to occur with vitamin D deficiency, including suboptimal bone and thyroid health," explains board-certified endocrinologist Brittany Henderson, M.D., who specializes in hormones in her clinical practice. "Higher levels of serum 25(OH)D [the biomarker for vitamin D status] have consistently been associated with healthy mood, optimal immune function, and more."*

For that reason, Henderson typically targets blood levels of at least 50 ng/ml—and she's far from alone in that.

Despite the nutrient's importance, vitamin D deficiency and insufficiency are incredibly common. Right now, around 29% of U.S. adults are considered straight-up vitamin D deficient4 (again, that means a level of less than 20 ng/ml), while 41% are vitamin D insufficient4 (below 30 mg/ml).

We know, we know, this can be pretty hard to wrap your brain around—but you really can't depend on food and time spent outside to keep your vitamin D status in a healthy place (a daily, lifelong endeavor).

While there are a few dietary sources of vitamin D (some natural, more fortified), we still can't typically get enough of it from our diets. "Unless you are eating sardines, salmon, or mackerel daily, there is a good chance your food is vitamin D insufficient," explains Henderson. 

And when it comes to the sun? There are some concerns here, too. Crouch points out that UV exposure and subsequent vitamin D production changes with the seasons, the latitude you're located at, your skin color, the amount of skin you have exposed, and the amount of time you spend in the sun. Your ability to produce vitamin D from sun exposure is also largely dependent on your age and decreases dramatically after the age of 50, adds Henderson.

Now that we've got that out of the way, you're probably wondering how much vitamin D you should take in supplement form.

Before you even worry about dose, make sure your supplement contains vitamin D3 (cholecalciferol), which is significantly more (up to 87% more5, to be exact) effective at raising and maintaining vitamin D levels in the body than vitamin D2 (ergocalciferol).*

From there, research6 has demonstrated that supplementing with 1,000 IU of vitamin D3 raises the average adult's serum D level by approximately 10 ng/ml, which means it takes 5,000 IU of vitamin D3 per day to raise your level to that goal of 50 ng/ml.*

In some cases of significant deficiency, though, it may take up to 10,000 IU (or higher) of vitamin D3 daily to meet the mark,* Henderson says. Heck, according to Crouch, even a couple of months at 50,000 IU per week may be necessary to correct a major deficiency.*

Another special circumstance to consider here: Overweight adults or those with obesity have vitamin D needs that are two to three times higher3 than those with a normal weight, so working with a health care provider to regularly monitor your vitamin D status and supplement regimen can ensure you truly get the amount of the nutrient you need to feel your best.*