Vitamin D vs. D3: What’s the real difference?

Vitamin D is an essential nutrient that plays a vital role in bone formation, muscle health, immune system function, and other processes in the body. When looking for products or supplements that contain vitamin D, you may come across the term vitamin D3. This might lead you to ask: what is the difference between the two, and which is most beneficial for me? In this blog, you will learn more about the difference between vitamin D and D3.

Table of Contents

• What Is Vitamin D?
• What Is the Difference Between Vitamin D and Vitamin D3?
• Symptoms of Vitamin D Deficiency
• What Is the Best Source of Vitamin D?
• How Much Vitamin D Do You Need Per Day?
• When Do You Need Vitamin D Supplements?

What is vitamin D?

Vitamin D is a fat-soluble vitamin, which means that the body can store it for future use. In addition to obtaining vitamin D through food or supplements, the body can also produce it with the help of sunlight. There are two types of vitamin D found in food: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3) (Harvard Health, 2023). Vitamin D3 can also be synthesized by the skin when exposed to ultraviolet B (UVB) rays from the sun.

What is the difference between vitamin D and vitamin D3?

Both vitamin D2 and D3 are collectively referred to as “vitamin D.” This means that there is no difference between vitamin D and vitamin D3 in name. However, there is a difference between vitamin D2 and D3:

• Vitamin D2: Also known as ergocalciferol, this form is found in plant-based foods exposed to UV light, such as mushrooms. Vitamin D2 is cheaper to produce than D3 and is often added to products like milk, cereal, and orange juice.
• Vitamin D3: Also called cholecalciferol, this is the type of vitamin D produced in the skin of humans and animals when exposed to sunlight. Vitamin D3 is found in animal products such as mackerel, salmon, trout, tuna, beef liver, and eggs.

Supplements and fortified foods may contain either vitamin D2 or vitamin D3. Both forms are active and usable by the body. However, studies have shown that vitamin D3 increases blood levels of vitamin D more effectively and keeps them stable for longer (Tripkovic et al., 2012). For this reason, some experts prefer vitamin D3 over D2, as it is found in more foods and is naturally produced by the body.

Symptoms of vitamin D deficiency

A vitamin D deficiency usually causes few or no noticeable symptoms at first, or the symptoms may be mistaken for other health issues. Serious symptoms often appear only when a deficiency has been present for a longer period. Symptoms of vitamin D deficiency may include:

• Muscle weakness
• Bone fractures
• Bone or muscle pain
• Fatigue
• Low mood
• Depression
• Increased susceptibility to illness

Source:  Cleveland Clinic, 2022

What is the best source of vitamin D?

Sunlight is the best natural source of vitamin D. With regular sun exposure, our bodies can produce enough vitamin D on their own. However, it can be difficult to get enough sun-derived vitamin D if you live in an area with little sunlight, spend little time outdoors, wear clothing that covers most of your skin, or have darker skin (Cleveland Clinic, 2022). In addition to sunlight, vitamin D can also be obtained through food and supplements.

How much vitamin D do you need per day?

The amount of vitamin D you need each day depends on factors like age, skin tone, and existing health conditions. An intake of 10 to 20 micrograms per day is sufficient for most adults. It is recommended not to exceed 100 micrograms per day (NHS, 2020). In addition to intake, blood levels of vitamin D are important. The reference range for a normal vitamin D level may vary depending on the test and lab used, but the following general reference ranges apply to adults:

• Deficiency: < 30 nmol/L
• Insufficient supply: 25 – 75 nmol/L
• Adequate supply: > 75 nmol/L
• Toxicity: > 250 nmol/L

Source: Amrein et al., 2020

When do you need vitamin D supplements?

To determine whether you need vitamin D supplements, you should first check if your blood level of vitamin D is low. This can be done through your general practitioner or with a home blood test. The Homed-IQ Vitamin D Test is a home-use vitamin test that involves taking a blood sample and sending it to a lab for analysis.

If your vitamin D level is low, you can take steps to raise it by increasing sun exposure and incorporating vitamin D-rich foods into your diet. For individuals who have difficulty making these changes or who have an increased need for vitamin D, supplements may be recommended. Always consult your doctor before taking supplements to ensure you are taking the correct dosage. Although supplements can be a useful way to boost vitamin D levels, taking them in excessively high doses or without medical need can be harmful to your health.

Would you also like to test for other vitamins in addition to vitamin D? With the Homed-IQ Vitamin Deficiency Test, you can check your blood levels of folic acid, vitamin B12, and vitamin D from the comfort of your home.