By Brant Cebulla, Vitamin D Council

It’s often stated that the human body can make 10,000 to 25,000 IU of vitamin D, maybe more, in a single session of full body sun exposure. How do we know that?

We measure your vitamin D stores by measuring 25(OH)D in your blood. When you input vitamin D, it gets sent to your liver to turn into 25(OH)D so the rest of your body can put it to use.

You can actually measure serum vitamin D in the blood before the liver has converted it to 25(OH)D. After a good day’s worth of UV exposure or large oral does of vitamin D, you’d expect serum levels to spike briefly, as the body needs some time to transport it to the liver.

Thus, we can start to compare how much serum vitamin D is in your blood immediately after sun exposure and how much serum vitamin D is in your blood immediately after you take a certain amount of supplement.

Click here to read the entire article in the latest issue of Smart Tan Magazine online.