Is Vitamin D3 the Same as Vitamin D

Is Vitamin D3 the Same as Vitamin D

We know that vitamins are good for us, and we also know that some are more important than others. One of these key vitamins is vitamin D – it’s so important that the government recommends supplementing with it from September to April. Sometimes, though, there can be some confusion between certain combinations and variations of vitamin D available on the market.

We’re here to clarify the difference between two versions of the vitamin: D and D3. Stay informed of the differences between the two vitamins, which are subtle but present. This will help you the next time you attempt to follow that government advice, or if you simply want to bolster your levels all year round.

Vitamin D in the Body

What’s interesting about vitamin D is that, unlike a lot of other vitamins, it’s created in the human body. When sunlight hits our skin, it starts a chemical reaction that eventually produces the vitamin. This is why supplementation is recommended during the darkest months of the year or if you have darker skin: not enough sunlight is being absorbed to generate a healthy amount of Vitamin D.

So what roles does vitamin D have in your body? One of the most well-known effects is supporting the immune system: one paper states that it has “important functions beyond those of calcium and bone homeostasis which include modulation of the innate and adaptive immune responses”. Of course, this point and the idea of taking it through winter has formed the belief that it helps to fend off colds, which isn’t completely unfounded.

If you ask a nutritionist the main benefit of vitamin D, however, they’ll tell you that it aids calcium absorption in the body. As you might know, calcium is important in bone health, maintaining their strength. You could drink all the milk in the world, but without enough vitamin D in your system not all of that calcium will be absorbed efficiently. And it’s important for everyone to get enough calcium, not just for the young and old.

The Different Kinds of Vitamin D

The question we pose in the title has an interesting answer: what we know as Vitamin D comes in around five different forms. It might be surprising to hear, but luckily we only need to focus on two major types: D2 and D3.

This begs the question of which kind of vitamin D you need in your diet, to meet your own personal needs. Let’s drill into both of these types to offer a little clarity.

Vitamin D3

Known scientifically as cholecalciferol, D3 is the version of the vitamin that is created by your body. And not just in humans, either: it’s also produced in the skin of all animals, in varying degrees. Because of this, the only way to take in vitamin D3 in your diet (aside from supplements) is animal products: oily fish, eggs and daily products. Naturally, this means those on a vegetarian and vegan diets can be prone to deficiencies. D3 supplements, on the vast majority, are made with animal products too, as many use sheep’s wool in their manufacturing process.

One important difference to vitamin D2 is that D3 is more easily metabolised by the body. To explain: both D2 and D3 are broken down in the liver into a compound called calcifediol, which is then spread around the body. According to a number of studies in the area, vitamin D3 raises the level of calcifediol in the blood much higher than D2, sometimes as much as 85% more effectively. This means you need a smaller dose of D3 to get your ‘overall’ levels back into healthy numbers.

This often makes vitamin D3 the go-to for those who want to increase their levels or take the government’s advice. So what about the other common type?

Vitamin D2

There’s one big difference between vitamin D2 (also known as ergocalciferol) and D3: D2 comes from plants and fungi instead of animals, such as mushroom. This makes it ideal for vegans – dairy-free milks are fortified with D2 since, as previously mentioned, it’s a common deficiency. Like Vitamin D3, D2 is converted to calcifediol in the body, just at a lower concentration that D3.

Which to Choose?

What’s important to remember is that these are both viable forms of vitamin D, and they will boost the levels of it in your system. The main difference is the vegan aspect of D2 and how D3 causes greater increases in calcifediol. Although, with the ability to buy high-concentration D2 supplements, and how little the body needs per day (around 10µg (micrograms), or 0.00001 of a gram), it means that the difference between the two types are slim in reality. There’s even vegan vitamin D3 supplements on the market now, made by extracting compounds from moss.

The general advice seems to be that any vitamin D is better than none, especially for the young and the elderly. With the support it can provide either D2 or D3 will work well – extra strength formulas of up to 125µg can get you back up to healthy levels if you know you have a deficiency.

Perfect Partners

Having high levels of vitamin D – whether D3 or D2 – is great for your health by itself, but there are other nutrients that can be taken alongside it that can really compound its effects:

  • Calcium is of particular benefit, since vitamin D facilitates its absorption in the body. One of its well-known benefits is supporting bone health, making it a go-to combination for those with osteoporosis. One scientific review of research into the pair of nutrients makes note the ‘bricks and mortar’ analogy when talking about the two – both work together and are just as important in helping to reduce bone loss and increase bone strength. Aside from this, calcium also contributes to healthy muscle function, helping the transmission of nerve signals to them.
  • Vitamin K, much like vitamin D, has an effect on bone density and health. It’s been shown to have “a positive effect on bone mineral density and decreases fracture risk”, according to one review. This makes it a perfect partner to take alongside vitamin D, if you’re really looking to bolster your skeletal strength.
  • Vitamin C is famously known to enhance the immune system, with many of us reaching for a source of it when we’re feeling under the weather. Taking both vitamin C and D together may give your body extra fortification during the winter months, when you’re most susceptible to illnesses like colds and flu.


The simple answer to the question “is vitamin D3 the same as vitamin D” is yes, but there’s more to the vitamin than that. With two variants that are used as supplement ingredients, it’s important to recognise the differences and, equally, their similarities. Whether it’s D2 or D3, they play a role so important in our body that official agencies have endorsed supplementing with them. If you’re vegan, have weak bones or simply want some assistance fending off the sniffles over winter, make sure you take your daily dose of D.

As always, if you have any concerns about supplementing or are on medication, check with your doctor before starting a new supplement regime.