By Calli | Licensed Chiropractor & Esthetician (DC, LE) | May 17, 2026
You are tired in a way that sleep does not fix. Your bones and muscles ache for no clear reason. You catch every cold that walks through the door. Before you blame “just getting older” or “just being busy,” there is a simple, overlooked possibility worth knowing about: your vitamin D may be running low — and the symptoms rarely look like what most people expect.
I am Calli, a licensed chiropractor in Los Angeles, and low vitamin D is one of the most common quiet contributors I see behind chronic aches, sluggish recovery, and stubborn fatigue. After 20 years in practice, I have watched patients chase the symptoms for months before testing finally connects the dots. Here are the 6 warning signs worth taking seriously, and what to actually do about them.
TABLE OF CONTENTS
- Why Vitamin D Is More Than a “Bone Vitamin”
- The 6 Warning Signs of Low Vitamin D
- Why Sun and Diet Alone Often Are Not Enough
- Who Is Most at Risk of Deficiency
- How to Test, Correct, and Monitor Your Levels Safely
- When to See a Healthcare Provider
QUICK SUMMARY
Vitamin D acts more like a hormone than a vitamin, with receptors in muscle, bone, immune, and nervous tissue. Low levels can quietly show up as persistent fatigue, deep bone and muscle aches, frequent infections, low mood, hair thinning, and slow wound healing. Sunlight and food rarely fully correct a true deficiency on their own. The honest fix is: test first, correct under guidance, and re-test — not megadose blindly.
WHY TRUST CALLI
I am a licensed Doctor of Chiropractic and licensed Esthetician with 20 years of clinical practice in Los Angeles. Chronic musculoskeletal pain, slow recovery, and “I just don’t feel right” complaints fill my schedule, and low vitamin D is one of the patterns I have learned to recognize and respectfully refer for proper testing. This article is educational — it is not a prescription, and I do not diagnose or treat vitamin D deficiency in my office.
Why Vitamin D Is More Than a “Bone Vitamin”
Most people learned about vitamin D as “the bone vitamin,” and that is true as far as it goes — it is essential for absorbing calcium and keeping bone density intact. But vitamin D receptors live in nearly every tissue in the body: muscle, immune cells, brain, even hair follicles. That is why low levels can look like so many unrelated complaints at once.
How Vitamin D Actually Works in the Body
Functionally, vitamin D behaves like a hormone. Your skin makes it from UVB sunlight, your liver and kidneys activate it, and from there it influences calcium balance, muscle function, immune regulation, mood, and inflammation control. When the supply runs low, the symptoms are rarely loud — they are vague, multi-system, and easy to write off.
The 6 Warning Signs of Low Vitamin D
These are the patterns I have learned to pay attention to in 20 years of clinical practice. None of them is diagnostic on its own. But when several show up together, that cluster is a reason to ask your doctor for a blood test rather than guessing.
1. Persistent Fatigue That Sleep Does Not Fix
This is the most common quiet signal. You sleep 7 or 8 hours and still feel like you are dragging through the day. Vitamin D plays a role in mitochondrial energy production; when levels drop, that low-grade exhaustion can become your baseline.
2. Deep Bone and Muscle Aches
Not the sharp pain of an injury — a dull, diffuse aching, especially in the lower back, hips, ribs, or legs. Low vitamin D affects bone mineralization and muscle function, and a slowly building “I just hurt everywhere” pattern is a real clinical clue.
3. Frequent Colds and Slow Recovery from Illness
Vitamin D helps regulate the immune response. People with low levels often notice they catch more respiratory infections, take longer to bounce back, or feel run-down after every small bug that goes through the household.
4. Low Mood, Especially in Lower-Light Months
The link between vitamin D and mood is not as simple as “more D, more happiness,” but research consistently shows associations between low levels and depressive symptoms. If your mood reliably dips in the darker months and lifts in the brighter ones, sunlight exposure and vitamin D are worth a conversation with your doctor.
5. Hair Thinning or Increased Shedding
Hair follicles have vitamin D receptors, and low levels are associated with certain types of hair loss. This is rarely the only cause, but combined with other signs on this list, it adds to the picture.
6. Slow Wound Healing
Cuts, bruises, and minor injuries that linger longer than they should may reflect impaired tissue repair. Vitamin D is involved in producing the compounds skin uses to heal, so chronically low levels can quietly slow recovery.
Why Sun and Diet Alone Often Are Not Enough
The cultural advice — “just get more sun” — is incomplete for many people, even in a sunny city like Los Angeles. Sunscreen, indoor work, clothing, age, skin tone, latitude, and time of year all change how much vitamin D your skin actually makes. And food is a surprisingly weak source: fatty fish, fortified milk, and egg yolks contribute, but you would need to eat a remarkable amount every day to correct a real deficiency through diet alone.
The Honest Truth About Supplements
For some patients, a properly dosed supplement, taken under guidance after testing, is the most reliable way to bring levels back into range. But this is exactly where I see people go wrong — buying a “high-dose” vitamin D off the shelf with no idea what their level actually is. Vitamin D is fat-soluble. Too much can be harmful. Test first, dose based on the result, and re-test. That is the entire approach.
Who Is Most at Risk of Deficiency
Some patients are simply more likely to be running low. The common risk factors include:
- Limited outdoor time or heavy sunscreen use
- Darker skin tones, which make vitamin D more slowly from sunlight
- Older age, as skin synthesis declines
- Higher body weight, which can sequester vitamin D in fat tissue
- Gut conditions that impair fat absorption
- Certain medications and chronic kidney or liver issues
If two or more of these apply to you and you also recognize symptoms from the list above, that is a perfectly reasonable reason to ask your doctor to run a 25-hydroxyvitamin D test.
How to Test, Correct, and Monitor Your Levels Safely
Here is the plain-language sequence I share with patients in office:
- Get a baseline test. A simple 25-hydroxyvitamin D blood test ordered by your primary care provider tells you exactly where you stand. Guessing is not testing.
- Correct under guidance. Your doctor can recommend a dose based on your actual level, your weight, and any other risk factors. Self-prescribing high doses long-term is exactly how people end up with vitamin D toxicity.
- Re-test after correction. Usually a few months later. The goal is reaching and staying in your physician’s target range, not climbing as high as possible.
- Support with sensible lifestyle basics. Reasonable midday sun exposure when your skin tolerates it, vitamin-D-containing foods, and managing the risk factors you actually have control over.
When to See a Healthcare Provider
Some symptoms warrant a proper medical evaluation rather than self-managing:
- Severe or worsening bone pain
- Unexplained weakness or muscle cramps that interfere with daily life
- Frequent infections that linger or recur
- Persistent mood symptoms that affect your work, relationships, or daily functioning
- Any combination of the warning signs above that has gone on for more than a few weeks
CALLI’S CLINICAL NOTE
One patient stays with me as a perfect example of how easy this is to miss. She came in for low-back pain that just would not settle, in her late 30s, hardworking, dragging through her days. The pain pattern was real and we worked on it, but as I listened to her describe the rest of her life — exhausted, achy in places that did not match the injury, catching every cold her kids brought home — I gently suggested she ask her primary care doctor for some basic blood work, including a vitamin D level. It came back significantly low. Her doctor put her on a correction plan, and over the next couple of months her energy lifted, her aches softened, and our musculoskeletal work started to actually hold. The chiropractic care alone could only do so much when the foundation underneath was depleted. That is the lesson I keep coming back to: address the structure and the soil together.
THE BOTTOM LINE
Low vitamin D is one of the most common quiet contributors to fatigue, aching, low immunity, and low mood — and one of the easiest to miss because the symptoms are vague enough to be blamed on anything. If you recognize several of the 6 warning signs in yourself, do not guess and do not megadose. Ask your doctor for a simple blood test, correct under guidance if your level is genuinely low, and re-test. Test first, then treat. That is how you actually move the needle.
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— Calli
DC, LE | Licensed Chiropractor & Esthetician | Address the structure and the soil together.
Medical disclaimer: This article is for educational purposes only and is not a substitute for evaluation by a qualified healthcare provider. Chiropractors do not diagnose or treat vitamin D deficiency. Any suspected deficiency should be evaluated with appropriate blood testing and managed with your physician. Do not start, stop, or change any supplement based on this article alone.