Boron deficiency in humans can cause a variety of symptoms, including impaired growth and development, weak bones and joints, poor coordination, fatigue, mental confusion or foggy thinking, difficulty concentrating or focusing on tasks, depression and anxiety. Additionally, boron deficiency has been linked to an increased risk of osteoporosis due to its role in calcium metabolism. Other signs may include skin problems such as eczema or psoriasis as well as weakened immune system function. It is important to note that these symptoms are often subtle and may be difficult to recognize without proper testing.