Have you jumped on the vitamin D bandwagon thinking more must be better? 

You’re definitely not alone. 

In the last few years, the number of people taking vitamin D has sky-rocketed, but did you know…

taking excessive amounts of vitamin D can actually be detrimental to your health. 

Maybe you started taking it during the pandemic or because your doctor prescribed a high dose due to a deficiency, and you simply never stopped. Or perhaps you stumbled upon articles or social media posts singing praises of vitamin D and decided to make it a daily ritual.

Either way, it’s important to recognize that long-term and excessive vitamin D supplementation can pose serious risks, especially if you haven’t been monitoring your vitamin D levels regularly through blood tests once or twice a year. 

In this article, we’ll dive into the potential dangers of overdosing on vitamin D and why it’s crucial to get your vitamin D levels checked if you’ve been supplementing for an extended period, especially at higher doses like 10,000 IU’s. 

So, let’s dig deeper into the complex world of vitamin D to help you make better choices for your overall health.


I used to believe that everyone should be taking a vitamin D supplement because of how widespread deficiency is in the US. We are inside more and don’t consume a lot of the foods that are higher in vitamin D like egg yolks, fatty fish and cod liver oil.

While there’s no question that having adequate levels of Vitamin D are absolutely vital for good health, many people have been taking high doses for a long-period of time and are now in excess. 

Every few months I come across lab results showing excessively high vitamin D levels (65+), and while stopping the supplementation usually helps regulate it, the longer it remains at high levels, the more harm it can cause (which we will discuss below). 

That’s why it’s incredibly important to have your vitamin D levels tested regularly. Unfortunately, many doctors don’t include vitamin D in their routine lab tests, along with other important markers like parathyroid hormone and magnesium to give us a fuller picture of what’s going on in the body. This oversight can lead to missed opportunities to address imbalances and ensure proper functioning of the body while it’s still easy to fix!

To be fair, MOST people I see have low Vitamin D but for those few who are running high and it continues to get overlooked for a long period of time, it can cause irreversible side effects.


Vitamins come in two main types: fat soluble and water soluble. 

Water-soluble vitamins such as Vitamin C and the B vitamins dissolve in water. These vitamins are easily eliminated through urine, which makes it difficult to overdose on them. However, since they are not stored in the body for long, it’s important to have regular intake of these water-soluble vitamins to meet your daily requirements.

On the other hand, fat-soluble vitamins like D, E, A, and K dissolve in fat, and it’s best to take them with fatty or oily foods for better absorption. Here’s the important thing to be aware of — taking excessive amounts of any of these fat-soluble vitamins can lead to their accumulation in the liver and fatty tissues which can lead to excessively high amounts. This is unlikely to occur from sun exposure or dietary sources which is why we need to be smart about how we supplement.


  • Nausea and vomiting
  • Poor appetite
  • Excessive thirst
  • Frequent urination
  • Constipation
  • Fatigue and weakness
  • Muscle pain or weakness
  • Bone pain
  • Headaches
  • Confusion or difficulty thinking
  • Elevated blood calcium levels (hypercalcemia)
  • Kidney problems (in severe cases)


The main issue with excessive amounts of vitamin D is that it disrupts the balance of calcium in the body, leading to various symptoms and complications like:

  •  Hypercalcemia 
    • Increased absorption of calcium from the intestines can cause nausea, vomiting, constipation, frequent urination, confusion, and even kidney problems.
  • Kidney stones
  • Digestive issues
    • like abdominal pain, diarrhea, and constipation.
  • Fatigue and weakness
  • Excessive bone loss


Calcium, vitamin D, vitamin K, and magnesium all work closely together, and any imbalance in these nutrients can have a ripple effect on many of the body’s systems. That’s why balance and proper ratios of these nutrients are crucial for optimal health. 

  • Calcium is the key mineral required for building and maintaining strong bones and teeth. It provides structural support to the skeletal system and is involved in various physiological processes, including muscle contraction, nerve function, and blood clotting. 
  • Vitamin D helps with the absorption of calcium from the intestines and into the bloodstream. It also promotes reabsorption by the kidneys to maintain calcium balance in the body.
  • Magnesium activates Vitamin D and helps to convert it into its active form. It transports calcium in and out of cells making sure it’s being used properly within the cells.
  • Vitamin K directs calcium into the bones so it doesn’t get deposited in soft tissues and arteries. It also helps with blood clotting and maintaining a healthy heart and blood vessels.

The synergistic teamwork between these nutrients ensures that calcium is effectively absorbed, utilized, and directed to the bones, where it is needed for strong skeletal structure.

Unfortunately, many people are deficient in those other nutrients for various reasons, creating widespread osteoporosis and cardiovascular issues. 

Vitamin D deficiency is common because we spend more time indoors and don’t get enough sunlight or consume foods rich in vitamin D like egg yolks and fatty fish. 

Vitamin K deficiency is also widespread as people often don’t eat enough leafy greens, fermented foods, or grass-fed dairy. 

Magnesium is challenging to get enough of due to modern farming practices which have depleted magnesium levels in the soil. In addition, many of the processed snacks and foods we fill ourselves up on don’t provide much magnesium either. The most magnesium rich foods include pumpkin seeds, dark chocolate, spinach, swiss chard, almonds, and cashews. Additionally, certain health conditions, chronic stress, alcohol consumption, and certain medications  like (PPI’s for acid reflux, antibiotics, birth control, prednisone, and diuretics) can lead to magnesium loss in the body. 


Now let me be clear, this does not mean that you should just take a calcium supplement to balance it out. 

In fact, I rarely, if ever, recommend taking calcium supplements, and even when I do, it’s only in combination with those other crucial nutrients like Vitamin K, D, and magnesium. And even then, I have my reservations. While calcium plays a vital role in maintaining strong bones, it requires the support and synergy of the other nutrients to ensure optimal bone health.

Supplementing with only calcium, like many people are doing to prevent and reverse osteoporosis can be downright dangerous.

If you’re deficient in Vitamin D, K, or magnesium, the calcium supplement you consume may not be deposited in your bones but rather in your arteries, leading to artery calcification. Artery calcification can lead to narrowing of the arteries, increased risk of heart disease, stroke, peripheral artery disease, high blood pressure and kidney problems. It ain’t nothin’ to mess with!

Plus, it can cause the calcium to get deposited only on the outside of the bones, causing the bones to become hard on the outside but weak on the inside, making them more prone to fractures and shattering. 

It’s essential to recognize that calcium supplementation should not be done in isolation, despite many doctors’ recommendations. The presence of adequate Vitamin D, K, and magnesium is vital for proper calcium utilization and bone health and most people are deficient in the other vitamins — resulting in a recipe for disaster.

If you or someone you know is currently taking calcium supplements, I encourage you to dive deeper into this topic and gain a better understanding of the potential risks involved. It’s crucial to consider a comprehensive approach to bone health, which includes a balanced diet, weight-bearing activity, and professional guidance to ensure optimal bone strength and overall well-being.

Check out this article for more info on calcium supplements.



Especially if you have been taking high doses or taking Vitamin D for a long time, it’s crucial that you get your levels checked. 

We include Vitamin D in our comprehensive bloodwork panel at Flora Fauna Wellness along with other important markers that help us paint a more complete picture of your health. The bloodwork we run is much more comprehensive than your average doctor and checks for various markers that show us a pattern of how you’re absorbing vitamin D. We don’t rely on just one marker like Vitamin D to make a diagnosis.

You can also see your regular doctor for this but might need to give them a little extra push.

I suggest getting tested twice a year, in the Spring and Fall, so you can adjust your supplementation accordingly. In the summer, when we’re basking in the sun, you may not need as much, but during the gloomy winter months, you might require a boost to ward off seasonal blues.

Without checking your levels, you’re in the dark about where you stand. You could be riding high after a sunny summer and not need any supplementation come fall, or you might still be in the lower range and want to pump up the D for the impending winter doldrums. Plus, your Spring levels can shed light on whether “Seasonal Depression” is caused by something other than a vitamin D deficiency. 

We need this data to piece together your health puzzle.

The optimal Functional range for Vitamin D is between 35-65 ng/mL, although individual requirements vary based on ethnicity, genetics and other factors. 

If your Vitamin D is low, we dig deeper and look at other markers to confirm or rule out deficiency. We also want to find out why it’s low. Are you having trouble converting Vitamin D? Do you need more magnesium or a supplement with Vitamin K2? There’s a whole detective game to be played.

If your Vitamin D is high, chances are you’ve been taking a supplement. But if you’re not, do you consume an abnormal amount of Vitamin D fortified foods? Certain processed foods, cereals, milk, and orange juice have added synthetic vitamins that aren’t absorbed as readily as more natural forms of vitamin D. It’s rare to overdose from fortified foods, but it’s a possibility worth considering. Another scenario is certain medical conditions like sarcoidosis, tuberculosis, or lymphoma, which can trigger excessive vitamin D production.

Remember, vitamin D toxicity is quite rare, mostly stemming from excessive supplementation. If you’re worried about your levels or experiencing symptoms of vitamin D excess, it’s wise to consult a healthcare professional for proper evaluation and guidance.


The best and most efficient way to get Vitamin D is through the sun.

Our skin has the incredible ability to effectively convert sunlight into a usable form of vitamin D through photosynthesis. 

Our bodies are just not as efficient at absorbing vitamin D from food or supplements as they are at synthesizing it from sunlight exposure. While you might get a sunburn (which we don’t recommend either), it’s very unlikely to get Vitamin D overload from being in the sun. 

Plus the sun has way more benefits than JUST Vitamin D production. It also regulates our circadian rhythm (which controls our wake, sleep, appetites, hormones, mood, etc), neurotransmitter and feel-good endorphin production, immune system function, and blood pressure regulation. 

Depending on where your levels are, you can gauge just how much sun you need in order to stay in balance.


While the exact amount of sun exposure needed can vary based on factors like skin type, geographic location, and time of year, as a general guideline, getting 10 to 30 minutes of sun a day is ideal.  

The safest times to sun are before 11 and after 4pm. I always recommend my patients go for a walk first thing in the morning (within an hour of waking) to regulate their cortisol levels. This not only helps get you some Vit D but it also can improve your sleep, regulate your appetite, mood and so much more. It’s a simple habit that’s an absolute game changer.

During this time, it’s important to expose your face, arms, and legs to the sun sans sunscreen or coverage, as it can hinder vitamin D synthesis.  It’s only for 15-30 minutes and you shouldn’t burn during that time.




I recommend getting Vitamin D from whole food sources like my fave — Rosita’s Cod Liver Oil (found in my online pharmacy here where you can get professional grade supplements shipped directly to you).  It’s high-quality, wild cod and doesn’t give you the fish burps. They also use an extensive extraction process that you can view on their website. 

Choosing a whole food source, like cod liver oil, provides a higher bioavailability (aka better absorption) of vitamin D compared to synthetic supplements. 

Plus, cod liver oil offers the added benefits of vitamins A and omega-3 fatty acids, which work synergistically to promote overall health and balance in the body. Vitamin A helps maintain the delicate balance between vitamins A and D, ensuring optimal health and preventing potential imbalances that can arise from isolated vitamin D supplementation. 

Omega-3’s and natural antioxidants help facilitate the absorption, utilization, and effectiveness of vitamin D in the body. 

When it comes to choosing between Cod Liver Oil and isolated Vitamin D supplements, going for Cod Liver Oil is a win-win situation. Not only do you get more value for your money in terms of multiple vitamins, but you also reduce the risk of overdosing on Vitamin D.


If you have issues with taking Cod Liver Oil for any reason, then at the very least I recommend you take a vitamin D3 and stay away from the synthetic and poorly absorbed D2. Double check your label if you’re currently taking a Vit D supplement to confirm which kind you have.

As we discussed above, it’s also important to take D with K2 so finding a supplement like Xymogen’s D3K2 is a great option if you are have low levels <25 and need to get them up ASAP. Again, you should always be checking your levels and not continuously taking vitamin D for all eternity once you start. You want to get your levels back to that sweet spot between ~35-65 and maintain it via sunlight. 

So let’s wrap this up and summarize: taking Vitamin D supplements can indeed support your health, but it’s essential to strike a balance and avoid excessive doses. 

Regularly checking your Vitamin D levels, especially if you’ve been supplementing for an extended period, is crucial for maintaining optimal health and avoiding potential risks associated with elevated levels. 

Remember, everyone’s needs are unique, and consulting with a functional medicine practitioner can help determine the appropriate dosage for your individual requirements. 

So, let’s embrace the sunshine vitamin responsibly and ensure our health stays in check!

Disclaimer: This blog post is intended for informational purposes only and should not replace professional medical advice. Please consult with a healthcare professional before making any changes to your supplementation routine or treatment plan.