Calciferol vs D3 help me understand dosage?

May 20, 2021 1:52 AM

I'm taking vitamin D supplements because I have low vitamin D levels. Up to now, calciferol (the purple tablet you take once a week) has not been available because of covid demands so I've been taking a daily Vitamin D3 instead. My doctor wants me to change over to calciferol now that it's become available. Help me understand why? Communication with my doctor is a bit difficult at the moment with restricted appointments because of covid.

The Vitamin D3 I take is a dose of 1000 Iu per day. That's what my doctor and pharmacist recommended although I've seen much higher doses mentioned online.
Apparently calciferol, the once a week dose, is 50 000 Iu. Does That means I'll be getting quite a lot more vitamin D, doesn't it? Or is it more complicated than that? I've read up about the differences and there doesn't seem to be much consensus about which form is better.
I live in South Africa and get plenty of sun and still, somehow, low in vitamin D :)
I've noticed a definite improvement in my anxiety levels since I started taking vitamin D so I need to understand how changing might affect things.

posted by Zumbador to Health & Fitness (2 answers total)

Cholecalciferol is another name for vitamin D3. The other important vitamin D is ergocalciferol/D2. I haven't heard people say just calciferol, but maybe that's an SA thing (I'm in the US). They are both pro-vitamins that your body converts to the active version, chole/ergo calcitriol.

What you describe is the prescription strength version of cholecalciferol/D3, to be taken once weekly for a set number of weeks, to build up your vit D stores relatively quickly. Generally you'd switch back to the once daily OTC version for maintenance after your levels normalize, although there are some medical conditions where people stay on 50k IU indefinitely.
posted by basalganglia at 3:34 AM on May 20, 2021 [3 favorites]

(In the US, branded Calciferol is D2, but as a green softgel not a purple tablet.)
posted by Iris Gambol at 11:40 AM on May 20, 2021 [2 favorites]