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What’s the Best Form of Vitamin D for Absorption?

My simple mission for Vitalized Future is to help you live a healthy, energized and optimized life.

Some examples of where we’ve covered lifestyle optimization include:

  • Optimizing sleep by turning off your devices before bed
  • Optimizing your workouts by hitting the weights in the evening
  • Optimizing supplements by taking them at certain times of day

If you’re reading this, then chances are you’re most interested in optimizing supplements, so we’ll explore in this article another way to optimize supplements (that not many people are aware of.)

You see, taking the best form of supplement is just as important as taking the right supplement, as quite often the form determines how well the supplement is absorbed.

(It turns you aren’t quite what you eat, but what you absorb.)

Vitamin D is no exception to the rule, so this article explores the best form of Vitamin D for optimal absorption.


Vitamin D Tablets vs Capsules

It’s rare that supplements arrive in their pure form as they need to be “held together” to be consumable.

(There are a few exceptions where the pure form is a powder, such as Creatine and Glutamine.)

So the first factor we need to consider is whether Vitamin D tablets or capsules are more effective for absorption.

To answer this, let’s recall that vitamin D a vitamin.


But what may be less obvious is that all vitamins are either water soluble or fat soluble.

Water soluble vitamins dissolve in water and hence are best taken with a pint of water.

Fat soluble vitamins, however, are best taken with fat which helps with absorption into the blood stream.

Any guesses which category vitamin D falls under?

Those who guessed fat-soluble are correct.

That’s right, Vitamin D is a fat-soluble vitamin.

Now if we look at the ingredients of your typical Vitamin D tablet, we’ll see:

  • Calcium Carbonate
  • Vitamin D
  • Microcrystalline Cellulose
  • Magnesium Stearate
best form of vitamin d for absorption

Amount of fat in the above?

A grand total of zero.

Now let’s look at the ingredients of your typical Vitamin D capsule:

  • Olive Oil
  • Vitamin D
  • Softgel Capsule (Gelatine, Glycerine)

Here, we have Vitamin D contained within a fat (olive oil).

So for the reason explained above, Vitamin D capsules are absorbed better than Vitamin D tablets.

Vitamin D2 vs Vitamin D3

Many people aren’t aware that there are actually 2 types of Vitamin D:

  • Vitamin D2 (Ergocalciferol)
  • Vitamin D3 (Cholecalciferol)

Vitamin D2 is mainly derived from plant sources exposed to UV light (i.e Mushrooms), whereas Vitamin D3 is only found in animal sources (i.e. Oily fish, Liver and Eggs).

As far as this article is concerned, Vitamin D3 appears to be more effective at raising your Vitamin D levels.

Now let’s look at the why…

Our liver metabolizes Vitamin D2 into 25-hydroxyvitamin D2 and Vitamin D3 into 25-hydroxyvitamin D3 – both of which are referred to as Calcifediol.

However, Vitamin D3 seems to yield more calcifediol per unit than Vitamin D2 (Source).


To summarize, there are 2 variables which determine how well your Vitamin D supplement is absorbed:

  1. Is it contained in a fat/oil?
  2. Is it Vitamin D3?

Luckily, there are many Vitamin D supplements out there which fit both the above criteria so it shouldn’t be too difficult to find a great Vitamin D supplement.

(In fact I’ve ranked 7 of my favourite Vitamin D supplements here, so please check it out.)

I know this is a fairly short article compared to the other in-depth posts, so let me know if you’d like me to go in more detail anywhere.

Or perhaps you guys like them kept short?

Let me know your thoughts in the comments below, and thanks for sticking to the end.



Tuesday 26th of April 2022

I heard you need magnesium to absorb vitamin D. Is this correct?


Wednesday 1st of June 2022

Magnesium certainly helps Vitamin D absorption!


Saturday 6th of June 2020

Thanks - really helpful, clear and easy to understand! 👌🏼


Saturday 6th of June 2020

Thanks for the kind feedback, Sandy :)