UK Flag menu arrow

Select your country

Track my results

What Is The Difference Between Vitamin D & Vitamin D3?


We have all heard that we need Vitamin D and its health benefits have been praised for their essential impact on our overall well being and immunity, and its deficiency causing known cardiovascular implications, but what exactly is Vitamin D? How does it differ from Vitamin D3? Is one better than the other? Let’s take a look!

What is Vitamin D?

Vitamin D, known as the “sunshine” vitamin, is a hormone the body makes and a nutrient we eat and absorb- and one of the most common vitamin deficiencies in humans. It’s important to recognise what healthy vitamin d levels are.

It is fat – soluble, meaning it dissolves in fat and oil and is stored in our liver and fatty tissue. It helps the body retain calcium and phosphorus needed for strong bones.

Also, Vitamin D has a unique ability as it can be synthesised in the skin from exposure to sunlight, so it’s not strictly a vitamin as we know it and is technically a hormone.

There are two main forms of Vitamin D in the body: D2, known as ergocalciferol and D3, cholecalciferol. They do the same thing but have different molecular structures. D2 comes from plant sources like fungi, whereas D3 comes from animals, including people.

So, we have a range of sources available to us through UV exposure, eating foods rich in D3 like oily fish and egg yolk, fortified foods and vitamin supplements.

Related Read: How To Flush Vitamin D Out Of Your System?

What Factors Make It More Difficult To Absorb Vitamin D?

Certain disorders and environmental conditions can make it more difficult for the body to absorb Vitamin D

Irritable bowel syndrome, cystic fibrosis and chronic pancreatitis can make it much more difficult for the body to absorb Vitamin D as it disrupts its primary absorption via the lymphatic system in the small bowel.

Those who live in climates where there is less sun exposure (basically the whole of the UK between October and early March!) are also less likely to get enough Vitamin D as it is difficult to get through food alone.

Those more at risk of Vitamin D deficiency are recommended to take a supplement. 10 micrograms a day is the recommended amount according to NHS guidelines for a typical adult.

Related Read: How Much Vitamin D Do You Need?


Symptoms of Vitamin D Deficiency

Symptoms of Vitamin D deficiency include:

  • Fatigue and tiredness
  • Frequently getting sick or infections
  • Bone and back pain
  • Depression
  • Muscle pain
  • Impaired wound healing
  • Hair loss

Vitamin D deficiency is incredibly common and as the symptoms can be non-specific, it can be hard to spot and you’re probably wondering how to measure your vitamin d levels? Well, we recommend for anyone in the risk of deficiency group to take a blood test to find out if they are getting enough of this essential nutrient and consider supplementation if not as sadly, we cannot all take a flight to a sunnier climate.

Now we have covered some basic facts about Vitamin D, you might be wondering what supplements are best to take and what the differences are between vitamin D and D3. Keep reading to find out!

So, is Vitamin D3 better than Vitamin D2?

Vitamin D3 is known to be more effective than D2 as it yields more calcifediol which is the main form of vitamin D that circles in the body. If you have a choice, there is evidence to suggest D3 is slightly better due to it leading to a higher contribution to the body’s vitamin D stores, so it is usually the preference for vitamin D replacement therapy. If you think you have a vitamin d deficiency then you can order a vitamin d blood test and receive your results within a few days!