How Much Vitamin D Supplement Do You Need?

Sep 19, 2023

Having normal vitamin D levels is essential for a healthy immune system.

In the office, I guide my patients on the exact amounts they should take. I have been reluctant to make specific recommendations online because of the variability among readers. However, a very comprehensive article about vitamin D levels and replacement guidelines was published last year. I agree with the author’s assessment and will summarize the guidelines.

With fall coming, flu, RSV, and Covid numbers will be spiking. Now is a perfect time to pay attention to your vitamin D supplementation and ensure your immune system is in top shape.

It is very hard to get optimal vitamin D levels from sunlight and diet alone.

Here is how I would use these guidelines:

If you have medical conditions or are pregnant, talk to your provider and use their recommendations in place of these.
If you are already taking dosages similar to these, have your vitamin D level checked prior to making any changes.
If you aren’t taking vitamin D, use these guidelines to get started. It can take 2-3 months or longer for your levels to get to optimum, so be sure to get your vitamin D level checked after 3 months.
The minimum optimal level is 50ng/ml. We like our patient’s levels between 50ng/ml and 70ng/ml. Most national labs label the results normal at 30ng/ml. If your provider tells you that your vitamin D is normal, be sure to ask for the exact number. I see patients all the time with levels of 30-35ng/ml who have not been placed on vitamin D by their providers because the report said greater than 30ng/ml was normal.
I see patients who take vitamin D until their levels are normal and then quit. Whatever factors made your vitamin D low to begin with are likely still present, so you generally need to stay on vitamin D supplementation once your levels normalize.
In general, we prefer vitamin D supplements that are combined with vitamin K2. The combination of both is beneficial to bone health as well as immune health.

Take a Quality Vitamin D

The only reason we are in the vitamin business is because Lori’s vitamin D was low for a prolonged time and did not respond to store-bought vitamin D. It wasn’t until she bought a high-quality (but expensive) vitamin D that her levels started to rise. Further research helped us understand the difference in manufacturing and fillers that are placed in vitamins, leading to poor quality and/or poor absorption.

5000iu vitamin D capsule that has vitamin A and vitamin K2 in it.

Liquid vitamin D, which has 5000iu per dropper, and vitamin K2. The advantage of this is you can scale the dosing. For example, you can take 1.5 droppers full if you need 7500iu per day or .75 droppers full if you only need 3750iu per day.

These are the recommended supplement doses and the reference they were taken from.