What Are the Side Effects of Vitamin D3?

In a world that increasingly sees people spending more and more time indoors in front of screens, getting the right amount of D3 is challenging. Produced by the body in response to sunlight exposure, D3 is critical to maintaining good overall health by safeguarding our bones and bolstering our immune system.

But here's the problem: our modern lifestyle often limits our time spent in the sun – particularly as we get into the darker and colder months. Thankfully, it’s easy to find a high-quality vitamin D3 supplement to fill the gap.

However, with so many supplements on the market, are we in danger of taking too much D3? And if so, what are the side effects? Read on to find out.

In this article:
What is Vitamin D3?
What are the side effects of too much Vitamin D3?
How likely am I to take too much D3?
What do the guidelines say about D3?

Taking your D3 in a liquid form can help you find your optimal dose. Try the Vivo Life liquid Vitamin D3!


What is Vitamin D3?

Vitamin D3, or cholecalciferol, is a crucial nutrient that our bodies produce naturally when our skin is exposed to sunlight. This vitamin plays a critical role in maintaining healthy bones and teeth, supporting the immune, brain, and nervous systems, and regulating insulin levels.

However, getting sufficient sunlight has become a challenge in today's world. Many of us spend a significant portion of our day indoors to earn a living, reducing the opportunities for natural sunlight exposure. Moreover, living in areas with limited sun during certain seasons can contribute to Vitamin D3 deficiency.

Many people do not get the necessary levels of Vitamin D3 that the body needs to function optimally. In fact, a report from the UK's National Institute for Health and Care Excellence (NICE) estimated that about 1 in 5 people in the UK have low levels of Vitamin D3.

This deficiency underscores the importance of supplements. A high-quality vitamin D3 supplement can be the simplest way to ensure you get enough D3, especially in the winter.

However, with more and more D3 supplements coming to the market, are we at risk of taking too much?

What are the side effects of too much Vitamin D3?

Thanks to increased media coverage, people are becoming more aware of D3 deficiencies and the importance of supplementing. However, this surge in supplementation has also led to a rise in cases of Vitamin D3 overdose, where individuals consume the nutrient in quantities exceeding the recommended daily intake. Holick (2007) suggested that daily intakes above 4000 IU for adults can be seen as excessive. However, the precise amount can vary based on individual health factors.

So what are the risks?

Here are the potential side effects associated with taking too much Vitamin D3:

Weakness: An excessive intake of Vitamin D3 can lead to a noticeable decline in physical strength and energy, manifesting as muscle weakness and a general sense of fatigue. (Bolland et al., 2018).

Nausea and vomiting: Overconsumption of Vitamin D3 can sometimes upset the stomach, leading to feelings of nausea or even instances of vomiting, causing discomfort and distress (Bikle, 2014).

Hypercalcemia: In extreme cases, taking too much Vitamin D3 can lead to hypercalcemia, where there’s too much calcium in the blood. This can have detrimental effects on the heart and kidneys.(Souberbielle et al., 2010).

It's important to stick to the recommended dosage guidelines to avoid these side effects. The current scientific literature suggests an upper limit of 4000 IU per day.

If you’re considering supplementation, choose a high-quality supplement that’s third-party tested for contaminants. We also prefer a liquid form, as you can customise how much you want to take (unlike with tablets).

If you think you could be suffering from a D3 overdose, then it’s important to see a medical professional as soon as you’re able.

How likely am I to take too much?

The chances of you accidentally getting too much are slim. It’s virtually impossible to get too much D3 through food and sun exposure alone. However, with supplements, it’s essential to follow the dose on the back of the box.

While the maximum intake is generally 4000 IU daily, that doesn’t mean you should supplement with that. You will naturally get some D3 from sunlight during your day (assuming you step outside at all), and many plant-based foods contain D3. Tofu and plant milk are often fortified with it. That’s why our liquid D3 supplement contains 2000 IU.

There are two simple steps to avoiding too much D3:


1. Take a measured dose. We recommend taking your D3 in a liquid form so you can adjust your dosage manually if you’d prefer. We recommend taking 2000 IU per day.
2. Be cautious of taking multiple supplements (like multivitamins). If you take multiple vitamin complexes that contain D3, you might be getting more than you need.

What do the guidelines say about D3?

Following the recommended guidelines will ensure you don’t overdose on D3…but it’s also nowhere near enough.

Many health organisations, including the NHS, suggest a daily intake of around 400 to 800 IU for adults.

However, several studies argue that a higher daily intake, such as 2000 IU, is far more beneficial – especially in modern lifestyles that often limit sun exposure, a primary natural source of the vitamin.

These newer recommendations are guided by the potential benefits of increased Vitamin D3 intake on bone health, immune response, and overall well-being, without causing adverse effects.


Choose a better Vitamin D3

In light of this, supplementing with Vitamin D3 in the winter is essential for most people in the Northern Hemisphere. Depending on where you live, it might be worthwhile taking it year-round.

At Vivo Life, we’ve designed our Liquid Vitamin D3 to be flexible. You can easily adjust your dose as you see fit. For instance, you may want a higher dose if you know you won’t be outside much and it’s winter.

With the Vivo Life subscription service, you can get Vitamin D3 delivered to your door at only £0.13 per day for your recommended dose. Our D3 also contains K2 for enhanced absorption.


Holick, M.F. (2007). Vitamin D toxicity redefined: Vitamin D, co-morbidity, and satisfaction with life. The American Journal of Clinical Nutrition, 85(1), 6-18.

Souberbielle, J.C., Body, J.J., Lappe, J.M., Plebani, M., Shoenfeld, Y., Wang, T.J., Bischoff-Ferrari, H.A., Cavalier, E., Ebeling, P.R., Fardellone, P., Gandini, S., Gruson, D., Guérin, A.P., Heickendorff, L., Hollis, B.W., Ish-Shalom, S., Jean, G., von Landenberg, P., Largura, A., Olsson, T., Pierrot-Deseilligny, C., Pilz, S., Tincani, A., Valcour, A., & Zittermann, A. (2010). Vitamin D and musculoskeletal health, cardiovascular disease, autoimmunity and cancer: Recommendations for clinical practice. Autoimmunity Reviews, 9(11), 709-715.

Bikle, D. (2014). Vitamin D metabolism, mechanism of action, and clinical applications. Endocrine Reviews, 34(2), 33-88.

Bolland, M.J., Grey, A., Avenell, A., Gamble, G.D., & Reid, I.R. (2018). The effects of vitamin D supplementation on musculoskeletal health: a systematic review, meta-analysis, and trial sequential analysis. The Journal of Clinical Endocrinology & Metabolism, 103(11), 3995-4014.

NHS. (n.d.). Vitamin D. Retrieved from https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/