Woman taking vitamin D supplement for optimal whole-body health

How Much Vitamin D is Too Much?

Too much of a good thing can be very bad, indeed. Take vitamin D—just don’t take too much vitamin D! Case in point: a man who decided to wildly exceed the recommended dosage with a whopping 150,000 IUs (international units) of vitamin D a day, which is more than 30 times the daily dosage of a typical vitamin D3 supplement. As the British Medical Journal reported, he ended up dealing with quite a few side effects of too much vitamin D. After the fact, the man was very eager to share his story, which quickly became mainstream as it was reported on by multiple outlets such as CNN and MSN.

Many people are now concerned that they could be taking too much vitamin D—but fortunately, if you follow the dose on the bottle (which clearly this gentleman did not), you don’t have anything to worry about; vitamin D supplements are generally considered safe when taken in proper doses.

That being said, your vitamin D status is something you want to monitor closely. While consumers should make sure they are not taking too much of any compound (i.e., vitamin, mineral, herb) they should be particularly attentive to the dosing of fat-soluble vitamins such as vitamin D. That's because these nutrients stay in the body far longer than water-soluble vitamins. As an added safety measure, vitamin D levels should be periodically monitored with a 25-hydroxyvitamin D blood test to ensure that your numbers are where they should be.

Most of the time, of course, you're checking your levels to make sure you're getting enough vitamin D; vitamin D deficiency is far more common. So what should your vitamin D levels be, exactly—and how do you know whether you’re taking enough vitamin D to experience all of the benefits of the sunshine vitamin?

Let’s explore the many factors that go into vitamin D status—and how to ensure yours is optimal.

What is vitamin D?

Vitamin D is the superstar of the letter vitamins. That's because vitamin D is the only vitamin that is both a hormone and a vitamin. As a hormone, vitamin D is produced by your body and receptors for it are located on every cell. Vitamin D3 (cholecalciferol) is the most common form taken as a supplement and is casually known as vitamin D (although you can also find vitamin D2 as a supplement).

Most commonly recognized as being important for bone health, vitamin D actually plays many important roles in our overall health, including support for:

  • Cardiovascular health
  • Brain health
  • Immune health
  • Kidney health
  • Already-healthy blood pressure…and more!

Given these whole-body benefits, it's no wonder that vitamin D status has been linked to overall health–nor is it surprising that vitamin D3 supplements are among the most popular dietary supplements on the market.

Why take vitamin D supplements?

A constellation of peer-reviewed research suggests that vitamin D supplementation supports our general health and wellness. In 2022 alone, several meta-analyses were published which offered particularly compelling evidence to support the need for vitamin D supplementation. A meta-analysis is often done when there is a range of data from different studies as it provides an average of the pooled results and saves time as an added bonus.

The results of these new analyses associate vitamin D supplementation with:

  • Support of respiratory health when faced with immune challenges
  • Maintaining strong hip bones and bone health among the elderly
  • Promoting healthy insulin sensitivity
  • Cardiovascular health

Taking a multivitamin can give you the benefits of vitamin D along with the whole host of other nutritionally essential vitamins and minerals, as well as various other valuable nutrients.

How do you get vitamin D?

There are three ways to get vitamin D:

1. Sun exposure.

Our skin produces vitamin D in response to sunlight. People who live in year-round sunny climates tend to have higher D levels than those who don’t—but even they may need vitamin D supplementation since everyone's body may respond somewhat differently to UV exposure. Plus, protection measures, while important for the skin, can limit our body's production of vitamin D.

2. Diet.

It's hard to get enough vitamin D from food alone, but there are a number of healthy foods are good sources of vitamin D. Some healthy and naturally D-rich options include eggs and fish like wild salmon (which is also a great source of omega-3). There are also D-fortified foods such as orange juice and oatmeal. You can also get vitamin D from plants and mushrooms, but these foods only offer vitamin D2 (ergocalciferol); for the superior vitamin D3 form (cholecalciferol), you're going to have to go with animal products.

Pro tip: Many of these foods provide additional nutritional value aside from supporting your vitamin D status—so eat up!

3. Vitamin D supplementation.

As mentioned, the common cholecalciferol form of vitamin D3 is an effective way to avoid vitamin D deficiency and achieve optimal vitamin D levels. Since you can't get vitamin D3 from plants, vegetarians should supplement with vegan vitamin D3.

With prudent sunlight exposure and adequate vitamin D supplementation, complemented by diet, you should be on your way to optimal levels of vitamin D.

Who needs vitamin D supplementation?

Most people can benefit from taking vitamin D. Since it's unlikely that you're getting enough vitamin D from the sun and from diet, vitamin D supplements are going to be a good idea for many individuals. A blood test of your serum 25-hydroxy-vitamin D concentrations will tell you if you have a vitamin D deficiency—if so, you can adjust your vitamin D supplementation strategy accordingly.

Additionally, certain groups of people should be especially attuned to their vitamin D levels. For example, it’s important for postmenopausal women to follow a comprehensive bone support regimen that includes vitamin D supplements, calcium and more.

Vitamin D supplementation: How much should you take per day?

When it comes to vitamin D supplementation, doses should be personalized—and a high dose isn't necessary for everyone. Generally, most people will need to take between 5,000-8,000 international units (125-200 mcg) to reach optimal levels of vitamin D. Those with naturally darker skin tones are more likely to experience vitamin D deficiency, since vitamin D levels tend to naturally be lower. Multivitamins will also supply some vitamin D; a high-quality multivitamin like Life Extension Two-Per-Day Multivitamin supplies 2,000 IUs (50 mcg) per serving.

Pro tip: Optimize your vitamin D supplementation by also taking vitamin K. These two vitamins function as a tag-team duo to support healthy absorption of calcium from the intestines, and then proper absorption and incorporation of calcium into the bones. All the calcium supplementation in the world would derive no bone health benefits without vitamins D & K!

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What is too much vitamin D?

Taking 60,000 IU a day is associated with toxicity—that’s the equivalent of taking seven times the daily dosage of a higher-dose vitamin D3 supplement!

What happens if you take too much vitamin D?

Taking too much vitamin D leads to build up of calcium in the blood, which can impact your energy and digestion.

How much vitamin D do you get from the sun?

Some outdoor adventurers living in sunny areas might be able to get most of their vitamin D from sunlight, but two people with the exact same sun exposure can produce significantly different serum 25-hydroxyvitamin D concentrations. It varies from person to person, but those who are dark skinned will produce much less from the same amount of sun exposure as someone more fair-skinned.

Approximately 42% of Americans have vitamin D deficiency, but for Black and Hispanic individuals, vitamin D deficiency is at significantly higher prevalence of 82% and 69%, respectively. One study in Norway found that if Caucasians spent 30 minutes in the midday summer sun—they experienced a rise of 25-hydroxy-vitamin D equivalent to taking 10,000-20,000 IUs (a high dose); research shows that Black individuals will have to spend 6 times longer in the sun to achieve a similar rise in serum 25-hydroxyvitamin D concentrations.

How to know your vitamin D blood levels?

Vitamin D is measured by a blood test that calculates 25-hydroxyvitamin D, a circulating form of vitamin D. It’s a good idea to get your levels checked before supplementing and then have them periodically monitored after starting a vitamin D supplementation regimen. A follow-up test of 25-hydroxyvitamin D is really your only way to ensure you’re not getting too little or too much vitamin D. You can include a vitamin D test when doing a routine check for your total blood count and lipids profile.

What are normal levels of vitamin D?

There’s no straightforward answer to this question, since multiple health authorities have given different opinions on how 25-hydroxyvitamin D concentrations in the blood should be classified.

For example, the U.S. Endocrine Society offers three classifications of vitamin D status:

  • Deficiency: < 20 ng/mL
  • Insufficiency: 20-30 ng/mL
  • Sufficiency: > 30 ng/mL

Of course, “sufficient” isn’t the same as “optimal,” or the amount you’d need to be at the top of your game, so to speak. Other authorities define optimal levels as between 40-60 ng/mL. At Life Extension, we go a step further and suggest serum 25-hydroxyvitamin D concentrations between 50-80 ng/mL for optimal health.

In other words, better safe than sorry! Just don't be like the man in the news who took way too much vitamin D. A healthy dose of 5000-8000 IU per day of vitamin D, targeting a blood level of 50-80 ng/mL, may be the best way to ensure you safely get all of the optimal health benefits of the sunshine vitamin.

Is there a way to calculate an optimal vitamin D intake?

There is no way to know for sure you’re getting an optimal intake without testing 25-hydroxyvitamin D!

Is it better take vitamin D in a softgel or capsule?

Results from a preliminary study by Life Extension suggest that vitamin D may be better absorbed through a softgel than a capsule, however further studies are required.

About the Author: Chancellor Faloon is a graduate of Florida State University with a bachelor’s degree in Biological Sciences. He is dedicated to disseminating guidance on achieving better health and wellness. He has had various roles in the company, but scientific writing has always been his top priority. Chance has also raced in multiple full and half marathons.


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