Many people reach for their daily vitamin D supplement without giving it a second thought — after all, it’s widely known as the “sunshine vitamin” and celebrated for promoting strong bones and a robust immune system.
But pharmacists are now raising concerns: taking too much vitamin D can quietly put your kidneys, heart, and bones at risk. The gap between a healthy dose and a harmful one might be narrower than most realize.
Vitamin D has earned its reputation as a vital nutrient essential for bone health and immune function. Our bodies naturally produce it when sunlight hits the skin, and it’s also found in certain foods and supplements.
Yet, an increasing number of people are unintentionally overdosing. Experts caution that excessive vitamin D intake can have serious consequences.
Recent data reveals that about half of UK adults don’t get enough vitamin D, often due to limited sun exposure. To compensate, roughly one in six adults take vitamin D supplements regularly. While supplementation can be beneficial, high doses over extended periods may cause more harm than good.
Jana Abelovska, Superintendent Pharmacist at Click Pharmacy, explains the science behind vitamin D absorption in an interview with Surrey Live:
“Getting vitamin D from your diet is ideal, supported by supplements like tablets, gummies, capsules, or sprays. Since vitamin D is fat-soluble, it’s best absorbed when taken alongside healthy fats, such as yogurt, nuts, or avocado.”
Abelovska points out that for most adults between 19 and 70, the recommended daily amount is 15 micrograms (600 IU). While many multivitamins include safe amounts, some standalone vitamin D supplements offer much higher doses — which can become problematic.
“Because vitamin D dissolves in fat, it accumulates in the body more readily than water-soluble vitamins,” she warns. “Too much over time can cause hypercalcemia, a dangerous condition where excess calcium builds up in your bloodstream, potentially damaging your kidneys, heart, and weakening bones.”
She stresses that 4,000 IU (100 micrograms) per day is the upper safe limit for adults. Consistently exceeding this threshold can lead to serious health risks.
The NHS backs this advice, stating clearly:
“Do not take more than 100 micrograms (4,000 IU) of vitamin D daily, as it could be harmful. This recommendation applies to adults, pregnant and breastfeeding women, older adults, and adolescents aged 11 to 17.”
Final Thoughts
Vitamin D is unquestionably important — but like all good things, moderation matters. Appropriate supplementation supports bone strength and immune health, but taking too much can stealthily damage your organs over time. Always read supplement labels carefully, avoid stacking multiple vitamin D products, and consult your healthcare provider before upping your dose. Used thoughtfully, the sunshine vitamin can be a powerful ally for your health.