Side Effects and Warnings

Boron is potentially toxic, although humans tend to rapidly excrete it and therefore boron does not usually accumulate in high levels. In adults, it is believed that adverse reactions in doses below 10 milligrams of boron per day are less likely to occur, and there are few reports of toxicity. Large doses may result in acute poisoning. There are fatal case reports of infants who have been exposed to boron by mouth or on the skin. Historically, a honey and borax solution was used to clean infant pacifiers, and topical boric acid powder was used to prevent diaper rash. However, these practices were associated with several infant deaths.

Boron toxicity may cause skin rash, nausea, vomiting (may be blue-green color), diarrhea (may be blue-green color), abdominal pain, and headache. Low blood pressure and metabolic changes in the blood (acidosis) have been reported. Agitation and irritability, or the opposite reaction (weakness, lethargy, depression) may occur. Fever, hyperthermia, tremors and seizure have been reported. Based on animal study, excess amounts of boron ingestion have been shown to cause testicular toxicity, decreased sperm motility, and reduced fertility. Hair loss has been reported with boron poisoning. Chronic boron exposure may cause dehydration, seizures, low red blood cell count, as well as kidney or liver damage.

Boron is proposed to increase blood levels of estrogen and testosterone, with mixed results of research. Boron may be associated with reduced blood levels of calcitonin, insulin, or phosphorus, and with increased levels of vitamin D2, calcium, copper, magnesium, or thyroxine. Exposure to boric acid or boron oxide dust can cause eye irritation, dryness of the mouth or nose, sore throat, and productive cough.