5 Signs and Symptoms of Vitamin D Deficiency Even Your Doctor Might Miss

Vitamin D Deficiency

Vitamin D is an essential nutrient for good health. Yet, many Americans are not getting enough of the “sunshine vitamin” to optimize their health. Could that be you?

Vitamin D is called the sunshine vitamin because exposing your skin to sunlight is the best source of this essential vitamin. Your body can make and activate vitamin D if you expose your skin to sunlight without covering it with clothing or sunscreen. The most challenging time to get enough vitamin D from sunlight is during the winter when there’s less direct sunlight and your skin is covered with clothing.

Don’t Underestimate the Importance of Vitamin D

Why is vitamin D so important for your health and well-being? You need a healthy vitamin D level for bone and immune health. Without adequate vitamin D, you absorb less calcium from your digestive tract and less makes it into your bloodstream and to your bones. Plus, vitamin D supports bone health, reigns in inflammation, and keeps your immune system on high alert against viruses.

Despite its importance, studies show 40% of the population is vitamin D deficient and the incidence increases with age and body weight. Despite the elderly being at higher risk, it’s not just older people who don’t have a healthy vitamin level; vitamin D deficiency affects young and middle-aged adults too. People with darker skin are at higher risk since they absorb less ultraviolet light from the sun to make vitamin D.

The best way to know whether your vitamin D deficient is to ask your physician to check your vitamin D level, but there are certain signs and symptoms that you might be short in vitamin D. Some signals that your vitamin D level is low are easy to miss, as they’re so subtle. Here are five symptoms of vitamin D deficiency that are so sneaky, even you may miss them.


Insufficient sleep, stress, or a poor diet can cause exhaustion, but if it persists, check your vitamin D level. Fatigue is a well-known symptom of vitamin D deficiency. If your vitamin D level is low, might feel zapped of energy even after a good night’s sleep or feel sleepy during the day. Too often, people don’t get the connection between low vitamin D and feel exhausted. There are many other causes of fatigue, including nutritional causes. For example, iron deficiency can cause fatigue. That’s why it’s important to get physical and lab studies if a restful night’s sleep doesn’t cure your fatigue.

Muscle Weakness

Muscle weakness is a hallmark symptom of vitamin D deficiency and it’s easy to confuse muscle weakness from vitamin D deficiency with old age in the elderly. Anyone over 65 with balance issues or at risk of falling should test their vitamin D level to determine if they have a vitamin D deficiency. The elderly are at a higher risk of vitamin D deficiency because they get less sun exposure and are less efficient at making vitamin D when the sun hits their skin.

Increased Colds and Respiratory Infections

Since vitamin D helps maintain healthy immune function, it’s worth checking a vitamin D level if you catch more colds and viruses than usual. Most healthy adults get around two or three colds per year. Vitamin D helps your immune system carry out its job of protecting against infection more efficiently. Based on a systematic review of 39 studies, vitamin D deficiency was associated with a higher risk of upper and lower respiratory tract infections. Vitamin D levels are usually lowest in the winter months when respiratory infections are the most common.

Depressed Mood

A down mood might be a sign of an overwhelming week at work, or other worries and concerns, but it could also be a subtle sign your vitamin D level is low. A 2013 analysis of multiple studies found that lower vitamin D was associated with a higher risk of depression. So, stepping out into the sunlight more often with your skin uncovered can boost your mood in more than one way. In addition to increasing your vitamin D levels, early morning sunlight helps set your internal biological clock. Don’t stay indoors so much!

Poor Sleep

Although the connection between low vitamin D and sleep is weaker than the other symptoms mentioned, there is an association between low vitamin D and poor sleep quality. A 2018 analysis of 9,397 people found that the risk of sleep disorders and sleep disruptions was greater in people with a low vitamin D level. It’s something to consider if you struggle with insomnia or wake up frequently during the night.

The Bottom Line

Now you know five “sneaky” signs of vitamin D deficiency that even doctors miss. If you have any of these symptoms, and they’re persistent, ask your healthcare provider to check your vitamin D level. You need a normal vitamin D level for mental and physical health, and low vitamin D is common in the general population. Don’t let your level fall too low.


  • “Vitamin D Deficiency: MedlinePlus.” 28 Feb. 2017, medlineplus.gov/vitaminddeficiency.html.
  • Mayo Clinic Proceedings. December 2003. Volume 78. Number 12.
  • Dawson-Hughes B. Vitamin D and muscle function. J Steroid Biochem Mol Biol. 2017 Oct;173:313-316. doi: 10.1016/j.jsbmb.2017.03.018. Epub 2017 Mar 22. PMID: 28341251.
  • Cai C. Treating Vitamin D Deficiency and Insufficiency in Chronic Neck and Back Pain and Muscle Spasm: A Case Series. Perm J. 2019;23:18-241. doi: 10.7812/TPP/18.241. Epub 2019 Aug 8. PMID: 31496497; PMCID: PMC6730953.
  • Hughes DA, Norton R. Vitamin D and respiratory health. Clin Exp Immunol. 2009;158(1):20-25. doi:10.1111/j.1365-2249.2009.04001.x.
  • Shipowick CD, Moore CB, Corbett C, Bindler R. Vitamin D and depressive symptoms in women during the winter: a pilot study. Appl Nurs Res. 2009 Aug;22(3):221-5. doi: 10.1016/j.apnr.2007.08.001. PMID: 19616172.
  • com. “20 Symptoms of Vitamin D Deficiency, According to Medical Experts”
  • Penckofer S, Kouba J, Byrn M, Estwing Ferrans C. Vitamin D and depression: where is all the sunshine?. Issues Ment Health Nurs. 2010;31(6):385-393. doi:10.3109/01612840903437657.
  • “Common cold – Symptoms and causes – Mayo Clinic.” 11 Jun. 2021, https://www.mayoclinic.org/diseases-conditions/common-cold/symptoms-causes/syc-20351605.

Related Articles By Cathe:

How to Avoid Vitamin D Deficiency in the Winter

Winter Nutrition: How to Stay on Track with Your Diet All Winter Long

Is Vitamin D Important for Controlling Weight?

Can Vitamin D Improve Your Body Composition?

5 Factors That Negatively Affect Your Vitamin D Level

Can Vitamin D Improve Exercise Performance?

Hi, I'm Cathe

I want to help you get in the best shape of your life and stay healthy with my workout videos, DVDs and Free Weekly Newsletter. Here are several ways you can watch and work out to my exercise videos and purchase my fitness products:

Get Your Free Weekly Cathe Friedrich Newsletter

Get free weekly tips on Fitness, Health, Weight Loss and Nutrition delivered directly to your email inbox. Plus get Special Cathe Product Offers and learn about What’s New at Cathe Dot Com.

Enter your email address below to start receiving my free weekly updates. Don’t worry…I guarantee 100% privacy. Your information will not be shared and you can easily unsubscribe whenever you like. Our Privacy Policy