Vitamin D researchers and scientists recommend a vitamin D level of 40-60 ng/ml (100-150 nmol/L). Nearly 90% of US adults are below this recommended level!

Testing is the first step – based on your current blood level an appropriate dose of vitamin D can then be determined. Re-testing is necessary to ensure the target blood level has been reached.

Check your level today!

Why is this Important?

Everyone responds differently to vitamin D…  For the same dose taken, individual vitamin D level response can vary by a factor of six or more. In other words, what might be enough vitamin D for one person may not be enough for another.

Vitamin D is needed by virtually every cell in the body, and is essential for hundreds of processes each and every day. It acts as a protector and regulator of all cell types, tissues, and organs, and is able to enhance the functioning of each system of the body to help keep us healthy.

Vitamin D deficiency has been linked to:

Depression & Anxiety Schizophrenia, Alzheimer’s Disease, ADHD & Autism

High Blood Pressure, Peripheral Artery Disease, Coronary Heart Disease, Atrial Fibrillation

Colds & Flu, Pneumonia & Acute Respiratory Distress Syndrome (ARDS), Asthma, Tuberculosis

Neuromuscular Pain, Weakness, Injury

Rickets, Osteoporosis Fracture

Diabetes, Crohn’s Disease, Cancer, Multiple Sclerosis, Psoriasis

Infertility, Preterm Birth & Prenatal Complications


How the Guess Your D Challenge Works

Guess Your Level and Determine Your Target! Start with a guess of your current vitamin D level. Determine your target level and for what health goals you want to achieve that target. Experts recommend a level of at least 40-60 ng/ml (100-150 nmol/L), although a higher level may be desired for certain concerns such as cancer and auto-immune conditions. Write this down somewhere you can refer to it later, along with something to keep you inspired or motivated.

Step 1
Order your home vitamin D test kit
(Include other nutrients or levels of your choice).

Step 2
Complete the questionnaire about your health and habits, including supplement intake and sun exposure. This helps identify why a vitamin D level may or may not be as expected, and it contributes to our research as well!

Step 3
Get your vitamin D result and see how close it is to your guess.

Is your level where you want it to be? If so – GREAT!
Keep up the good work and continue participating in the project to provide more data on what it means to have a healthy vitamin D level.

If your level is not in your target range, follow the next steps:

Step 4
Use the D*calculator to determine an adjusted vitamin D supplement amount and educate yourself on other factors that affect vitamin D levels.

Step 5
Track your changes and re-test in 3-6 months
(or sooner if trying a loading dose).

Step 6
How did your changes affect your vitamin D level? Did you reach your goal? Determine if additional adjustments are needed… repeat again if necessary.

FINALLY… Share your vitamin D story! Was your level what you expected? What did it take to reach your target? Have you noticed any changes in your health or how you feel? What insights did you gain from the challenge?  Tell those you love, share on social media, or email us to let us know what you learned at jen @grassrootshealth.org.

Invite others to guess their D level and learn how their health could benefit from vitamin D.

Enroll and Order Tests Today!

Download a PDF Version of the Challenge Here

Memorial Day Sale! Save 15% off orders of $100 or more with code MEMORIAL24. Not valid on the T1D Prevention Test Kit. Sale ends 5/28/24 at 11:59pm PST.