Osteomalacia means soft bones. Unlike osteoporosis, which makes bones thin, osteomalacia makes them weak and soft because they don’t mineralize properly. Most often it’s caused by low vitamin D, but other problems can block the minerals bones need. If you feel deep bone pain or unexplained muscle weakness, this page tells you what to watch for and what to do next.
The most common cause is vitamin D deficiency. That can happen from not getting enough sun, poor diet, or trouble absorbing nutrients from the gut (conditions like celiac disease, Crohn’s, or after some stomach surgeries). Certain medicines — for example, long-term anti-seizure drugs or some tuberculosis drugs — can also lower vitamin D levels. Chronic kidney disease and some rare inherited disorders can lead to low bone mineralization too.
Symptoms are often vague at first: aching bones, especially in the hips, lower back, legs, or ribs. You may notice muscle weakness that makes climbing stairs or standing up from a chair harder. Fractures from minor falls can happen. Lab tests may show low vitamin D, raised alkaline phosphatase (ALP), and sometimes low calcium or phosphate.
Doctors diagnose osteomalacia with blood tests and imaging. The key blood test is 25-hydroxyvitamin D — levels below about 20 ng/mL point to deficiency. ALP is often high when bone turnover increases. X-rays can show characteristic changes, and in rare or unclear cases a bone biopsy confirms the problem.
Treatment is straightforward in many cases: replace vitamin D and calcium, and treat any underlying issue. Typical approaches used by clinicians include a course of higher-dose vitamin D to correct deficiency followed by a maintenance dose. A common correction plan is vitamin D 50,000 IU once weekly for several weeks, then a daily maintenance dose (often 800–2,000 IU), but your doctor will choose the right dose for you. Calcium supplements help if dietary intake is low. If malabsorption, kidney disease, or medication effects cause the problem, those need targeted care too.
Many people begin to feel better within weeks of starting treatment: less bone pain, better strength, and fewer fractures over time. Your doctor will recheck vitamin D, calcium, and ALP to watch progress.
Practical prevention tips: get safe sun exposure when you can, eat vitamin D–rich foods (fatty fish, fortified milk, eggs), and consider a daily vitamin D supplement if you’re at risk. If you have digestive disease, a history of bariatric surgery, take enzyme-inducing drugs, or have kidney problems, mention this to your doctor — you may need earlier testing or a different treatment plan.
If pain is severe, you have a new limp, or you fracture a bone after a minor fall, see a doctor right away. With the right tests and treatment, osteomalacia is often reversible and bone strength can improve significantly.