When Should You Check Your Vitamin D Levels After Starting To Supplement?
Congratulations if you've lately started taking vitamin D supplements. Though it may appear to be a minor change to your daily routine, that small softgel, pill, or tablet has a lot to offer—and can have a significant impact on your health and well-being. (Seriously, tell your pals to jump on board! After all, 41 percent of the population is deficient in vitamin D.)
According to functional nutrition dietitian Whitney Crouch, RDN, CLT, vitamin D helps maintain your bones healthy, supports your immune system, and promotes cardiovascular health—and given that nearly every cell in your body contains vitamin D binding sites, that's probably just the tip of the iceberg.
When you start taking that much-needed vitamin D supplement on a regular basis, you'll definitely want to know how long it will take you to notice a difference—and see your vitamin D levels rise. Here's a fast rundown of what you need to know about how vitamin D levels are determined, how to supplement for the greatest outcomes, and when to retest your levels after starting a supplement to see how it works.
What you should know about vitamin D levels.
First and foremost, some basic information on how health care providers and researchers assess vitamin D levels in the body—and what level to strive for.
If your doctor suspects you have a vitamin D deficit or insufficiency, a blood test will be ordered to check your total serum 25-hydroxyvitamin D—or 25(OH)D—the form of vitamin D that circulates in your blood. The level of 25-hydroxyvitamin D in your blood (your status biomarker) is measured in nanograms per milliliter.
Although many experts, like board-certified endocrinologist Brittany Henderson, M.D., recommend obtaining a level of 50 ng/ml to best support bone health, immunity, and more, you've certainly heard that 30 ng/ml is considered the basic cutoff for avoiding insufficiency.
(In fact, Henderson prefers to meet patients with levels between 50 and 100 ng/ml.)
Your provider will recommend a high-quality vitamin D supplement with a potency that meets your needs and takes your individual health considerations into account, depending on how far below the mark your vitamin D status is. They'll also suggest a vitamin D3 supplement, which is the bioactive form of the vitamin and is more effective at raising your status than D2. (Don't know where to begin? We put together a selection of our top-rated, high-potency vitamin D pills.)
While your vitamin D requirements may vary, keep in mind the following: In the average adult, 1,000 IU of vitamin D3 per day is required to raise 25(OH)D by roughly 10 ng/ml. To put it another way, it takes about 5,000 IU per day to reach 50 ng/ml, while some people may require much more. Working in collaboration with your health care physician, those who are overweight or obese, for example, require two to three times as much vitamin D (10,000+ IU per day) to obtain the same impact.
When should you get your vitamin D levels checked again?
So, let's assume your doctor confirmed with a 25(OH)D test that you need to obtain additional vitamin D into your system, and you started (and have faithfully followed) a daily vitamin D supplement program right away. You might be itching to monitor your vitamin D levels and see if your new habit is paying off—but hold on!
While we all desire instant pleasure, you'll need to be patient in this case. "Vitamin D is fat-soluble, therefore vitamin D supplementation replenishes vitamin D stored in fat in addition to serum levels," explains the researcher.
Henderson clarifies. "Serum levels begin to rise when these storage levels are replenished." *
As a result, she suggests, "waiting three months to retest your 25(OH)D status will assist give you a more accurate picture of how well your supplement has done in replacing your whole-body vitamin D levels." According to research, health care providers should wait 12 weeks before rechecking a patient's vitamin D status after starting them on a supplement or changing the potency of that supplement.
There's nothing you can do to speed up this process, but you can improve your chances of success by eating fat with your vitamin D supplement to enhance optimal absorption. (Keep in mind that it's fat-soluble!) Better yet, get a vitamin D3 supplement with a source of fat so you don't have to wait until snack or lunchtime to obtain your daily dose of the sunshine vitamin. (mbg created our vitamin D3 potency+ with a special blend of organic, virgin oils so you can get your D fix whenever it's convenient for you.) *
The takeout.
If you're using a high-quality vitamin D3 supplement to treat vitamin D insufficiency or genuine deficiency, which is defined as a vitamin D level of less than 20 ng/ml (which 29 percent of us reach), you should wait 12 weeks (or three months) before retesting your levels. If you don't, your results may not reflect the benefits you're getting.
Consult your doctor before beginning a supplement regimen if you are pregnant, breastfeeding, or using medications. When deciding which supplements are ideal for you, it's always best to consult with a health care expert.