Vitamin D and Hormones

Updated: Sep 9

I have had many women come to my practice because they have irregular periods. Either periods are missing, they're longer than the recommended 34 day cycle, or they are heavy and painful.


In this article I cover the benefits of vitamin D, its effect on our monthly cycle, and how you can make sure you have an optimal vitamin D level.


How does Vitamin D affect my period?


Vitamin D is important for many reasons. Without proper vitamin D levels, our body is not able to effectively absorb calcium and our immune systems become more vulnerable. But for our focus in this article is the link between vitamin D and our hormones.


Research has shown that there is a connection between menstrual cycle length and vitamin D levels. Studies found that low vitamin D levels (20-30 ng/ml) were present in twice as many women with longer cycles compared to women with vitamin D levels above 40 ng/ml. (1)

Low levels of vitamin D is linked with more painful periods, decreased fertility, and female pattern hair loss. (2),(3)


What level should vitamin D be at?

Most of the medical community agrees that levels above 20 ng/ml is sufficient. Functional medicine recommends a higher level of 50-70 ng/ml. The Vitamin D Council recommends maintaining serum levels of 50 ng/ml.

Vitamin D Rich Foods


Sunshine is the best way for us to get vitamin D, but unfortunately some of us are still unable to get adequate vitamin D. And for others (like myself) with fair skin we try to avoid too much sun because we don't want sunburn!


Alternatives to sunshine would be diet or supplementation. There are not many foods that contain vitamin D so supplementation is often the most consistent way to ensure adequate vitamin D.


Foods that contain vitamin D include:

  • Fatty fish (e.g. salmon, mackerel, sardines)

  • Cod liver oil

  • Grass-fed or Pasture-raised egg yolks and beef liver

  • Foods that have been fortified with vitamin D (e.g. milk, cheese, orange juice, cereal, and some non-dairy milk products)





Testing for Vitamin D Level


Vitamin D testing should be a blood draw. You can ask your doctor about ordering a test, or if you want to order your own test at wholesale cost you can order through Ulta Lab tests online. They usually have a Vitamin D, 25-Hydroxy test for $39.



Other tests to recommended if your period is missing or you have irregular cycles.


If it has been three months with no period, or you have an irregular cycle, I recommend having the following tests drawn.


  • FSH, LH, and Estradiol. Test on the 3rd day of your cycle. Both FSH and LH are hormones that are produced by the pituitary gland in the brain. These hormones signal the ovaries to produce follicles and thicken the uterine lining, both essential for ovulation and therefore menstruation. Estradiol is the main form of estrogen in a menstruating woman’s body. Estradiol can become dominant in the body and cause other hormones to decrease, leading to a common hormone imbalance.

  • Progesterone Test between days 19-22 of your cycle. Progesterone will rise after ovulation has occurred. Progesterone’s main role in your cycle is to thicken the uterine lining so implantation and growth can occur during pregnancy. You can also identify a hormone imbalance by comparing estradiol and progesterone levels.

  • Full Thyroid Panel The thyroid panel includes pituitary (brain) hormone TSH as well as the thyroid hormones - T3, T4, reverse T3, and thyroid antibodies. We can look at the communication between the brain and thyroid when a full thyroid panel is done.

  • Cortisol Cortisol is best tested through saliva and should be collected periodically in a 24-hour period in order to have the most comprehensive and helpful reading. Cortisol will fluctuate throughout the day, so we want to make sure it is rising and falling in a normal pattern. Elevated cortisol levels can be another reason why progesterone levels are too low.


DUTCH Hormone Panel This is by far my favorite and most comprehensive test out there for hormones. I run this test in my practice often and has been extremely helpful in identifying the hormones and detoxification pathways that need to be supported for healing and balance. The DUTCH panel is a simple at-home collection since it uses dried urine as the sample. You can collect your sample at home and send it back to the lab through the mail. This test should be interpreted by an experienced health provider for you to get the most out of the results.



The loss of your period can be overwhelming to try and figure out on your own. Finding a health professional who can help you understand the process and guide you through a supportive and natural healing process is key.





Interested in taking next steps to balancing hormones and healing your gut? Check out my Hormone Hub group program here!

Liz Riesen, Registered Dietitian

specializes in digestive and hormone imbalances. Often these conditions coexist and share common disruptive symptoms including mood changes, bloating, pain, irregular cycles, inflammation, and more. Liz is trained in identifying and healing food sensitivities, as well as balancing hormones naturally through nutrition and lifestyle.


Join me in the Hormone Hub and learn all about digestion & hormones.

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