It’s easy to blame work or a hectic house when you wake up tired or your back aches more than it should. Several vitamin D deficiency symptoms resemble ordinary stress, and a blood test as part of your preventative care routine can help your provider tell the difference.
Why Vitamin D Deficiency Is Easy to Overlook
You need vitamin D to absorb calcium from food, as the National Institutes of Health (NIH) notes in its clinician fact sheet. When levels run short, your body keeps blood levels steady by borrowing from your bones. Many people with low levels feel no obvious symptoms.
The NIH draws the line for deficiency at 12 nanograms per milliliter (ng/mL). Yet readings between 12 and 20 still fall short for bone health. In national survey data from 2011 to 2014, about one in 20 Americans tested below 12 ng/mL, and nearly one in five fell between 12 and 20 ng/mL.
10 Symptoms and What They Get Mistaken For
Here’s how each symptom tends to get explained away. Strength ratings come from NIH and MedlinePlus summaries.
| Symptom | Often Mistaken For | Strength of the Link |
| Ongoing fatigue despite enough sleep | Stress or a busy schedule | Reported, still studied |
| Bone pain or aching | Arthritis or getting older | Well established |
| Low back pain | Posture or an old mattress | Reported, still studied |
| Muscle weakness | Being out of shape | Well established |
| Muscle aches or cramps | Overdoing a workout | Well established |
| Low mood | Burnout or winter blues | Reported, still studied |
| Frequent colds | Flu season | Reported, still studied |
| Hair thinning | Stress or hormones | Reported, still studied |
| Slow wound healing | Age or a minor infection | Reported, still studied |
| Falls or fractures in older adults | Balance problems | Well established |
What the Research Says About These Symptoms
Bone and Muscle Symptoms Have the Strongest Evidence
The clearest evidence involves osteomalacia, a softening of the skeleton in adults after years of severe deficiency. Individuals with this deficiency often experience aching bones and muscle weakness. Low vitamin D over many years can also feed into osteoporosis, and weaker hips and legs make it easier to lose your balance.
Bone also breaks down faster around menopause, the NIH notes. Women can bring up density testing at a women’s wellness visit.
Evidence for Fatigue, Mood, Hair, and Infections Is Mostly Observational
Fatigue is murkier territory. Physicians at Cleveland Clinic explain that a severe deficiency can pull blood calcium down, and low calcium can leave you tired, crampy, and depressed.
In 14 observational studies cited by the NIH, people with less vitamin D were more likely to be depressed, but in nine pooled clinical trials, supplements didn’t meaningfully help. If you’ve felt down for weeks, that’s worth its own conversation about depression management.
Whether low vitamin D can cause anxiety is even less settled. Researchers behind a 2021 review in Clinics looked at 15 studies and found mixed results.
Supplements seem to help with colds. Researchers who pooled 25 trials for a 2017 paper inThe BMJ saw a modest drop in respiratory infections, mostly among people who started out very low.
Dermatology researchers have studied vitamin D, too. After pooling 81 studies for a 2024 paper in Frontiers in Nutrition, they found that about half of people with alopecia areata or female pattern hair loss were deficient. Similar links have turned up for back pain inPain Physician and for slow-healing wounds in the Journal of Wound Care. These are associations, and researchers haven’t shown that low vitamin D causes them.
Who Is Most Likely to Have Low Vitamin D
Providers trying to determine what causes low vitamin D usually start with three areas: skin production, absorption, and medications.
Skin production drops as people age, and darker complexions produce less vitamin D with the same sun exposure, according to MedlinePlus. Yet skipping sunscreen isn’t a healthy way to acquire vitamin D. The NIH calls ultraviolet light the most preventable cause of skin cancer.
Absorption gets harder with Crohn’s disease, celiac disease, or a history of gastric bypass surgery. Vitamin D travels with dietary fat, and each of these conditions interferes with how your gut absorbs that fat. Kidney and liver disease can also block its conversion into a usable form.
Medications such as steroids, certain seizure drugs, and some cholesterol medicines can lower vitamin D over time, according to MedlinePlus. Bring a full list of what you take, over-the-counter products included.
When a Vitamin D Blood Test Makes Sense
Most providers check a blood marker called 25-hydroxyvitamin D. It hangs around for about 15 days, the NIH reports.
In its 2024 guideline, the Endocrine Society said healthy people generally don’t need routine testing. A test makes more sense if you have symptoms, a related condition, or a medication known to lower vitamin D.
Taking far more vitamin D than you need can raise blood calcium enough to cause nausea, confusion, kidney damage, or an irregular heartbeat, according to MedlinePlus. If you already take a supplement, tell your provider the dose printed on the label.
Talk With a Provider About Symptoms That Linger
Thyroid problems, anemia, and diabetes can cause the same tired, achy feeling. Your provider may check for them with blood sugar screening and other labs.
Before you go, write down roughly when the fatigue or aches started and whether they worsen as days shorten. Medscape’s authors note that levels usually bottom out at winter’s end.
Schedule a Visit With Imperial Center Family Medicine
Providers at Imperial Center Family Medicine have cared for Triangle-area families since 1999 and can help you decide whether a vitamin D test is right for you. If you need bloodwork, you can have it drawn at the practice’s on-site Quest Diagnostics laboratory instead of driving to a separate lab.
First-time patients can read about the first visit ahead of time. Call 919-873-4517 or reach out online to find out whether vitamin D deficiency symptoms explain how you have been feeling.