Vitamin D3 (Cholecalciferol): Benefits, Side Effects & Dosage

What is Vitamin D3?

Despite its name, vitamin D is not technically a vitamin. Vitamins are nutrients that people can only obtain through diet. But the body produces vitamin D from exposure to sunlight, so it is actually classed as a prohormone (x). Without vitamin D, the body cannot absorb calcium. Not only does the body use these minerals to strengthen the bones and teeth, they are also necessary for the muscles to function properly, including the heart (x, x, x). It also supports the immune system and it may be a help weight loss aid.

However, the reason there are so many concerns about vitamin D deficiency is because it can be hard to get enough. There are very few food sources that contain vitamin D. Oily fish, cheese, egg yolks and beef contain some, but the best way to get it is from the sun (x). But it can be difficult to get enough UV exposure safely without damaging the skin. Sun damage can cause sunspots and even increase the risk of skin cancer.

Vitamin D2 vs. D3

There are different types of vitamin D with different benefits, including vitamin D2 and vitamin D3. Chemically, they are very similar and both help absorb calcium. The main difference between them is how the body produces them. Plants produce vitamin D2, while animals — including humans — produce vitamin D3. Therefore, vitamin D3 is more effective to maintain adequate levels in the human body than vitamin D2 (x).

Benefits of Vitamin D3

Bone Health

The risk of bone fractures increases with age, especially for women. However, studies have produced a wealth of evidence that claim that vitamin D supplements may significantly reduce the risk of bone fractures, especially in the hips. Research also claims that it can help reduce the risk of osteoporosis (x, x, x).

Research also links this vitamin with rickets, a condition that causes soft and weak bones, usually from vitamin D deficiency (x). It is not common in the United States, but patients living in cloudy climates or those who follow restricted diets are at risk (x).

Heart Health

Because calcium is necessary for maintaining healthy muscles, it might not come as a surprise that research associates low levels of vitamin D with heart problems. Whether a patient already suffers from cardiovascular problems or not, deficiency increases the risk for hypertension, heart disease, heart attack and heart failure (x).

Immune Support

Adequate levels of vitamin D in the body can give the immune system a boost, especially during the winter months when patients may not see the sun as much. Studies show that supplements can provide protection against illnesses, such as the common cold and flu (x).

Research also states that it may even help prevent multiple sclerosis (MS) (x). Patients at risk for MS or with a family history of the disorder may want to consider adding a vitamin D3 supplement to their daily routine (x). The vitamin may also help with insulin sensitivity, meaning it may help prevent type 2 diabetes. Research also indicates that it may help improve sensitivity in patients who have already developed type 2 diabetes (x).

Weight Loss

Vitamin D3 may also help with weight loss. Research shows that low calcium levels may increase appetite and raise the risk of an overactive appetite. Because it helps the body absorb calcium, vitamin D3 may help with appetite control and weight loss (x).

Reduced Cancer Risk

There are an encouraging number of studies suggesting that vitamin D3 with dietary calcium can help prevent the risk of certain types of cancer, especially breast, colon and prostate cancer (x). Medical researchers have not proven the relationship, but there is evidence that vitamin D supplements may provide some protection.

Cognitive Function

Medical researchers have recognized a connection between vitamin D3 and cognitive function. It may help reduce age-related cognitive decline. For example, Alzheimer’s disease is a type of dementia that affects memory and other cognitive functions and it may be related to vitamin D3 deficiency (x, x).

Benefits of Vitamin D3

Side Effects of Vitamin D3

In the correct dose, vitamin D is a safe supplement to take. However, exceeding the recommended dosage might cause side effects such as dizziness, headaches, dry mouth, muscle pain, bone pain, nausea, vomiting and unusual heart rhythms (x).


Taking excessive amounts of vitamin D may cause the body to accumulate too much calcium, resulting in a condition called hypercalcemia that causes the bones to weaken. It can also lead to kidney stones and in extreme cases it can interfere with heart and brain function (x, x).

Other Side Effects & Warnings

Patients who take medications for heart or kidney disease should speak to a doctor before starting a supplement regimen with vitamin D. It may also interact with some types of steroids and weight loss products, so seek medical advice before combining them (x, x).

Dosage for Vitamin D3

The recommended dosage for vitamin D3 (cholecalciferol) is 50 mg daily. For accuracy, use a milligram measurement scale to get a consistent dosage. It is important to consult with a doctor before taking this vitamin as a supplement, in order to avoid any adverse side effects or medication interactions. It does not treat any medical conditions, but it may benefit overall health.

 Why Take Vitamin D3?

Vitamin D is an important nutrient to the human body. It helps absorb calcium and promotes strong bones, possibly preventing bone fractures and retain bone density. It also helps strengthen the muscles, including those in the heart. Vitamin D can keep the heart strong and stimulate healthy blood circulation. Patients may even be able to reduce the risk of heart disease, heart attack and high blood pressure.

There are very few dietary sources of vitamin D — oily fish, cheese, egg yolks — but the most common way to obtain its nutrients is from sun exposure. However, it can be difficult to obtain enough of it without increasing the risk of skin damage from the sun.

Low vitamin D levels can lead to a deficiency, which can cause health problems. For example, people in climates that do not get enough sunlight may be at risk. However, vitamin D3 supplements can help patients ensure a healthy and consistent dosage.

The Bottom Line

Vitamin D3 is the most effective form of vitamin D. Doctors and health professionals strongly recommend it as a regular part of a daily routine. It provides protection for the bones, the heart and the brain. It helps prevent bone density loss and reduce the risk of bone fractures and osteoporosis, which increases with age. Also, it can help slow age-related cognitive decline, such as Alzheimer’s disease and other forms of dementia. Studies show that it may even reduce the risk of certain types of cancers, especially breast cancer, colon cancer and prostate cancer.

Vitamin D3 is important for human health, but it may be difficult to obtain an adequate amount because there are very few foods that contain it. However, supplements are a good way to get a consistent dosage all of these health benefits. Make sure to follow the recommended dosage for vitamin D3 as a dietary supplement. Supplements are not a cure or treatment for any illness and they do not completely prevent any condition. Always consult a doctor before taking any supplement to avoid any adverse side effects or medication interactions.

Author: James D