# To Supplement D3 or Not This blog provides extensive information on the sunshine hormone [Vitamin D](/vitamins/vitamin-d/vitamin-d). I believe it is important to make informed decisions, especially regarding your health. While some may find the large amount of information on Vitamin D overwhelming, when you invest a bit of time, you will learn about the intricacies of this important hormone. Your health should be worth it. What are we without our health? What good is it to reach 100 years of age while spending the last twenty years bound to a hospital bed?

First things first

While very few people in the Western world are not deficient in Vitamin D, there is a slight chance that you have sufficient Vitamin D levels. Therefore, your first step in considering whether you should supplement or not should be to get a measurement of your Calcifediol levels. At-home tests are available to give you quick results, but they don’t provide precise levels. They instead tell you whether you are deficient or not. The question is whether the cutoff levels align with your expectations. A proper laboratory test to clearly establish your blood levels would be more advisable. The turnaround is not as quick, and you may have to go to your physician for testing. In any case, testing your current blood levels should be the first step.

Deciding on target blood levels

There are many purported benefits of Vitamin D sufficiency. However, what exactly is sufficiency? Personally, I err at the higher end of the spectrum. This is because there is data on Indigenous people who have levels of 120 ng/ml and above. Comparing our levels to the levels of members of our overall deficient society makes no sense to me. Hence, I don’t subscribe to RDAs and warnings from organizations like the FDA (US) or BfR (Germany). You have to make your own decisions, and this blog should have enough information for you to make an informed one. Once you have decided on your target blood levels (look here for an idea) and you know your current levels, you can take action.

Considerations when supplementing

What are your current blood levels, and how far away are you from your target blood levels? These are the first questions you should ask. The following questions are where you live, how much UVB radiation you get on your unprotected skin daily, and whether you live in a temperate area where the radiation is inconsistent year-round. Clearly, your current health situation is an important consideration, as is your skin complexion. Your obesity status is primely important when supplementing Cholecalciferol. Also, check your current supplements, foods, and drugs to see whether they contain Vitamin D (D3 or D2).

Many of us use multivitamins. Perhaps you use different multivitamins, fortified foods, and drugs with Vitamin D. Tabulate all this and figure out how much IUs of Vitamin D you currently ingest per day. Note that some drugs contain Vitamin D2 at very high levels (typically 50.000 IU). If you take such drugs, talk to your doctor to replace them with D3 preparations, as they are more efficient. If you have a kidney deficiency and you are on dialysis, this is not for you, and you must supplement directly with Calcitriol, which is available as a drug. If you don’t get this drug, definitely discuss that with your doctor and get alternative opinions if you are not satisfied with their answer. At the end of your research, you should know how much Vitamin D you are currently taking. At the same time, this can help put your blood levels into perspective. Keep in mind your unprotected sun exposure time and the strength of UVB in your area.

Are you obese? Wait, don’t answer that directly; measure your body mass index and check if it is clearly below 30. If not, you need to consider supplementing much more Vitamin D than if your BMI is lower. The reason is that ingested Vitamin D preferentially enters fat and muscle cells. Thus, less of the Cholecalciferol in your supplement is available to increase your blood levels. In case you are above 30 BMI, also have your liver checked for nonalcoholic fatty liver syndrome. If your blood levels of Vitamin D are low and you supplement large amounts (>10,000 IU/day), your liver may not convert Cholecalciferol into Calcifediol. In that case, get a prescription for Calcifediol directly. If your kidney also doesn’t work (check Calcitriol levels in a blood test), you must get a prescription for Calcitriol.

If you are lucky enough to live in an area of eternal sunshine, California, anyone, and you get unprotected sun exposure, then you can probably get away with little supplementation; let the blood tests be your guide. Even if you get sun exposure, you may not produce enough sunshine hormone because you have a dark tint and, therefore, need more prolonged sun exposure. Due to the protective layers on our skin (clothes, sunblock) or our natural sunblock (Melanin), we don’t usually give our skin a chance to produce Vitamin D. Again, let your blood levels be your guide in the process of achieving Vitamin D sufficiency.

In summary, we must ensure that we can convert Cholecalciferol to Calcifediol and Calcifediol to Calcitriol. The latter is the active form of the hormone and the only form that has a biological effect. We must also ensure that enough Cholecalciferol reaches the bloodstream and that not all of it is sequestered in muscle and fat cells. Finally, we need to consider our current supplementation, our exposure to UVB rays, our blood levels, and the distance to our target levels.

What and how much to supplement

Now that you have established your status quo, you can decide what and how much to supplement. Two forms of Vitamin D are sold over the counter for supplementation. One, Ergocalciferol aka. Vitamin D2, is of plant origin and inferior to the Vitamin D3 produced by our skin. Steer clear of this version of Vitamin D. You should only consider supplementing with Cholecalciferol (Vitamin D3). How much depends on the considerations above and the distance to reaching your target blood levels. BTW, while UVA passes through some glass panes and you might tan while driving in your car, UVB doesn’t pass through the glass, so you won’t produce any Vitamin D unless you roll down the window.

I hope you understood from the rest of the blog that the production of Calcitriol, the active version of Vitamin D, is under strict control in healthy individuals. Hence, there is little chance to get the system out of whack if you are conservative in your supplementation. Also, remember, Calcitriol increases Calcium blood levels, so it might be a good idea to reduce Calcium intake when supplementing with high doses of Vitamin D. Vitamin K can aid in channeling Calcium to the appropriate locations (bones). Calcium dysregulation is no joke at all and needs immediate medical attention. Don’t go down that road. Here is a surefire way to get you hospitalized: Take high doses of Coral Calcium and combine that with high doses of Vitamin D and skip Vitamin K supplementation.

The proper decision about how to supplement is difficult (sorry, there is no magic number). Let’s say you are at 15 ng/ml and are, therefore, severely deficient (typical). In this case, supplement with high doses, e.g., 30,000 IU daily (always discuss such decisions with your doctor). Now, you would want to measure your blood levels every other month to see how they develop. You can decide whether to increase the daily supplement or decrease it from the changes in your Vitamin D blood levels over time.

Some reports (see Calcifediol levels) suggest constantly supplementing with 30,000 IU, which is too general for me. I suggest taking a data-driven approach and measuring your blood levels frequently until you settle on a particular supplementation strategy. After that, you can have it measured alongside your yearly bloodwork. This means you need a little time to settle on your individual supplementation plan, but it is worth doing this to stay healthy.

• Vitamin D
• D3
• Vitamins
• International Unit
• IU
• Supplement
• Cholecalciferol
• Blood Levels
• Calcifediol
• Calcium