The 4 Best At-Home Vitamin D Tests To Check Your Levels Of The Micronutrient

Vitamin D plays a crucial role in our immunity and the overall health of our bones, gut, and thyroid—but it's also one of the most common nutrient gaps in the world. While we can get vitamin D from certain foods, it's not enough to truly affect our levels of the "sunshine vitamin." 

Instead, one of the main ways we get this beneficial vitamin is from—you guessed it—exposure to sunlight. However the length of time needed to get enough vitamin D differs by person (season, latitude, skin tone, etc.), and it may require partaking in unsafe skin practices to reach the optimal amount. 

Considering how much of our time is spent sitting indoors at a desk or watching Netflix on the couch, it's no surprise that many people are still struggling to hit the recommended vitamin D intake levels of at least 3,000 IU per day (which is still on the low end). 

If you're curious about your own vitamin D levels, you can ask your doctor for a lab biomarker for vitamin D status called the serum total 25-hydroxyvitamin D test, i.e., the 25(OH)D test, to shed some light on the situation. When an appointment with your health care professional isn't an option, an at-home vitamin D test is another way to test your vitamin D levels from the comfort of your home. 

Below, learn everything you need to know about at-home vitamin D tests, as well as what counts as a vitamin D deficiency. 

Vitamin D1 is an essential fat-soluble vitamin that acts like a hormone in its active form. The micronutrient plays an important role in various bodily systems and functions, such as the musculoskeletal, immune, neurological, thyroid, endocrine, and cardiovascular systems. 

Along with supporting thyroid health2, it also helps both the innate and adaptive immune systems by promoting white blood cell function3 and aiding the immune system in defending against threats4. It also plays a role in gut health, supporting beneficial gut bacteria and the gut mucosal lining. 

Finally, vitamin D is key to healthy bones and strong muscles. It helps the body absorb calcium, which is essential for bones, and supports the body in maintaining a balance between calcium and phosphorus. 

Needless to say, it's not something you want to be deficient in—and lack of the vitamin has been linked to bone, thyroid2, autoimmune5, and mood issues, to name just a few.

It's estimated that 50% of people globally6 have insufficient levels of vitamin D, which are measured in nanograms per milliliter (ng/ml) clinically or sometimes referred to in nanomoles per liter (nmol/l) in research literature.

The Endocrine Society7 defines vitamin D deficiency as the level of 25-hydroxyvitamin (25(OH)D) of less than 20 ng/ml, and vitamin D insufficiency as a 25(OH)D result of less than 30 ng/ml. In other words, these are the baseline cutoffs for avoiding insufficiency and thus, numbers to avoid. Indeed, many health care experts and much scientific research push for levels closer to 50 ng/ml to support bone health, immunity, and whole-body health. 

For example, the Endocrine Society recommends a preferred range of 40 to 60 ng/ml; founder and director of the Anti-Aging & Longevity Center of Philadelphia Seema Bonney, M.D., recommends an optimal range of 55 to 60 ng/ml given the importance of the micronutrient—and she's not the only one. 

Board-certified endocrinologist Brittany Henderson, M.D., previously told mbg that the common 30 ng/ml baseline actually leaves clients underserved, and she personally recommends a higher level.

"As an endocrinologist, I know that achieving optimal serum 25(OH)D levels in the 50+ ng/ml range is imperative for immune health, bone health, and more," she explained. "Our population is heavily vitamin D deficient, and targeting an optimal level of 50 ng/ml has an enormous impact on all aspects of human health."

When testing your vitamin D levels, here is a simple and evidence-based guide for interpreting your 25(OH)D result:

An at-home vitamin D test checks the level of the circulating form of vitamin D in your blood. This is your serum total 25-hydroxyvitamin D, or 25(OH)D8 level. 

We receive vitamin D (vitamin D2 and vitamin D3) from foods, beverages, sun exposure, and certain supplements. That vitamin D is converted in our liver to 25(OH)D, the biomarker for vitamin D status in your body. You might also see this test referred to as the calcidiol 25-hydroxycholecalciferol test. 

The other type of vitamin D in our bloodstream and acting inside our cells is 1,25-dihydroxyvitamin D, which is the biologically active, hormone-like form. This doubly hydroxylated form of the nutrient is created when 25(OH)D is further converted by our kidneys and targeted tissues for use in the body. This form, also known as calcitriol, isn't typically measured by tests (except in a kidney disease clinical setting) because it is tightly regulated and does not stay in the body as long as 25(OH)D. 

Similar to tests run by your health care provider, at-home tests check the levels of your vitamin D status biomarker, 25(OH)D, using a blood sample. This requires pricking your finger with a lancet to either fill a vial of blood or collecting a sample on a collection card. 

At-home vitamin D tests are typically shipped directly to your home and require you to mail back any samples within a required time frame for accuracy; some options with vial samples may ask for a same-day return to prevent the blood from clotting. 

Sounds easy enough, right? As with any at-home tests, there are pros and cons to testing vitamin D at home versus in a lab or at a doctor's office.

The first advantage, of course, is ease. "One of the benefits of at-home testing is that you can take the test when it's convenient for you," explains Bonney. "Even if your doctor doesn't feel it's medically necessary to have this test done, with an at-home test you can still get the data to supplement as warranted."

However, it's important to feel supported in understanding your results, which will vary from company to company. "Like any other lab testing, you'll get a reference range, which doesn't tell you what optimal levels are," says Bonney. "These ranges are typically based on what most people are, not what they should be. Doing the test under the guidance of a physician who is focused on making sure you have the right amount of vitamin D is helpful to guide what your dosage of supplementation should be."

Another consideration is the margin for error. Leaving the test to a professional means you're not responsible for potential error (i.e., inherent variability) in your results. Some reviewers of at-home tests complain that they were unable to properly collect their sample—although typically companies are good about sending a replacement kit in these instances.

Deficiency in vitamin D can stem from a number of factors, such as poor nutrient absorption, lack of sun exposure, or more serious conditions, like liver or kidney disease. Functional nutrition dietitian Whitney Crouch, RDN, CLT, once told mbg those most at risk of vitamin D deficiency include:

Symptoms of vitamin D deficiency aren't always easily detectable because this micronutrient is so whole-body important. However, some symptoms (such as depression or bone loss) can be life-altering. You may want to take a deeper look at your vitamin D levels if you have any of the below symptoms or conditions:

If you think you're experiencing symptoms, the best course of action is to work with your health care provider to determine how to monitor your vitamin D levels and identify the root cause of your health concerns.

According to Bonney, for most people, vitamin D testing through a lab would be covered by insurance with the correct ICD-10 code(s) submitted by your health care partner. "But these at-home tests are not," she says. "And if your [at-home] levels are abnormal, this would warrant having them rechecked in a lab setting with proper phlebotomy" and an expert clinical opinion once the result comes in. 

However, most of the at-home testing companies on this list do accept payment from a Flexible Spending Account (FSA) or Health Savings Account (HSA), if those are insurance benefits available to you.

According to our expert, yes. But Bonney warns that the main variable to watch out for is you.

"In general, [at-home] vitamin D tests may be as accurate as lab tests done by phlebotomy, but they do need to be performed correctly," she explains. "This means washing your hands with soap and water (as per the CDC) to remove residue like lotions that can affect the results. It's also vital that you produce a blood drop sufficient to fill the testing strip; otherwise, you'll have an insufficient sample." 

Other possible variables include waiting too long before the blood sample is sent off and assayed for results, as well as testing method errors at the lab completing the assay, according to mindbodygreen's vice president of scientific affairs Ashley Jordan Ferira, Ph.D., RDN. 

"At-home vitamin D tests are really at-home blood samples that are mailed off for vitamin D assay (testing) at certified labs using fancy equipment and analytical methods," she explains. "While no assay method is 100% free of error, the gold standard method for accurately testing your vitamin D status is called liquid chromatography-tandem mass spectrometry9 (LC-MS/MS)."

From promoting strong bones and a healthy immune system to enhancing your sleep quality, vitamin D is a crucial nutrient that about half of the global population6 does not get enough of without proper vitamin D supplementation. 

An at-home test can provide some insight into your biomarkers from the comfort of your own couch. Just be sure to choose a test that makes you feel supported and doesn't break the bank. And remember: If you're concerned about the results of your at-home test, it's best to speak with your health care provider.