Toxicity symptoms have been reported at extremely high blood levels in cases where people took megadoses (very high doses) of vitamin D supplements for extended periods of time. Vitamin D levels greater than 100 ng/mL may be harmful. This will help you avoid potentially inappropriate or dangerous dosing. However, make sure to consult a healthcare professional on what dosage you should take. Keep in mind that people who are low or deficient in vitamin D may need to take much higher levels than the safe upper limit to reach and maintain optimal vitamin D levels. Her vitamin D levels were discovered to be 265 ng/mL, which equals 130,000 IU and is over 30 times the generally recommended safe upper limit of 4,000 IU per day ( 7). In another 2020 case report, a 56-year-old woman who took an average of 130,000 IU of vitamin D per day for 20 months in hopes of improving symptoms of multiple sclerosis was hospitalized for symptoms including nausea, vomiting, and muscle weakness. Most cases of vitamin D toxicity are caused by inappropriate supplement dosing and prescription errors.įor example, in a 2020 case report, a 73-year-old man developed vitamin D toxicity after taking 10,000 IU of vitamin D per day for many years ( 6). Recommendations on optimal vitamin D levels vary, but research suggests that levels between 30–60 ng/mL are likely optimal and may help protect against illness and disease ( 4, 5).Įven when taking high dose vitamin D supplements, it’s unlikely that a healthy person’s blood vitamin D levels would come close to reaching excessive or toxic levels. Hypervitaminosis D is defined as blood vitamin D levels over 100 ng/mL, while vitamin D intoxication is defined as serum levels over 150 ng/mL ( 3, 4). In order for vitamin D to reach toxic or dangerous levels in the body, it needs to exceed 100 nanograms (ng) per milliliter (mL). Signs of too much vitamin D include: Elevated blood levels What are the symptoms of vitamin D toxicity?

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