What Does it Take YOU to Get Your D to 40 ng/ml (100 nmol/L)?

Did you know your health could be greatly affected by making sure you have a vitamin D level of at least 40 ng/ml (100 nmol/L)? Help us help you.

Everyone responds differently to vitamin D; the same dose of vitamin D is likely to result in different vitamin D levels from one person to the next. There are certain steps that are essential to ensuring you have found the right dose of vitamin D and/or the right vitamin D routine (using sunshine, UVB, food, or other sources) for the level you are trying to achieve.

Discover Your Best Dose of Vitamin D by Following these Simple Steps

STEP 1 – Do you know what your vitamin D level is? Enroll and order your test to find your current vitamin D level

STEP 2 – Complete your online questionnaire as part of being a Citizen Scientist in the Vitamin D*action project

STEP 3 – Determine your target level. Are you at your target level? Experts recommend a level of at least 40-60 ng/ml (100-150 nmol/L), however, some research indicates levels over 60 ng/ml may be beneficial for certain conditions such as autoimmune diseases and cancer.

STEP 4 – Need to boost your level? Use the D*calculator to see how much vitamin D it may take to reach your target. Opt for the Loading Dose for a quicker boost.

STEP 5 – Implement your new supplement dose and/or routine (will you include sunshine or an indoor UVB device, increase vitamin D rich foods, etc.?), and optimize how your body absorbs and utilizes vitamin D with co-nutrients and these simple steps.

STEP 6 – Re-Test! This step is VITAL to make sure you have reached your target level, and to ensure you are not taking too much! Re-testing after 3-6 months is recommended or sooner if using a loading dose. Adjust your intake and/or routine again if needed, or consider evaluating vitamin D co-nutrients or other factors if you did not achieve the result you expected.

STEP 7 – Repeat, adjust, repeat, until you have reached your target! Experts suggest testing a minimum of twice each year to make sure target levels are maintained, as levels tend to be highest at the end of summer and lowest at the end of winter.

Be confident that you are getting enough vitamin D to maintain your target level…

Join the D*action project.

Test Now!


Supplementation does not always provide the expected change in vitamin D level. It is vital to TEST, ADJUST, RE-TEST and REPEAT to make sure that the daily dose or vitamin D routine is effective at achieving and maintaining the desired target vitamin D level. For example, an analysis of 5,442 GrassrootsHealth participants who completed at least two vitamin D tests showed that two-thirds (67%) reached a vitamin D level of at least 40 ng/ml on their second test – leaving 1/3 of those who re-tested still below the 40 ng/ml target level.

About GrassrootsHealth’s Vitamin D*action Study

Since its founding, the GrassrootsHealth Nutrient Research Institute’s Vitamin D*action study has grown into the world’s largest population field trial on vitamin D, thanks to the thousands of participants who have contributed as “Citizen Scientists.” By joining the GrassrootsHealth project, everyone has provided valuable health information to make important health discoveries and methods to help Move Research into Practice — while also measuring their vitamin D level and receiving education and tools to help track, achieve and maintain healthy levels for themselves.

Test your vitamin D level at home while joining thousands of others world-wide in collaborating on nutrient research.
Enroll & Test Now!

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