Mona Lisa may have been sick when she sat for Leonardo da Vinci as he created his masterpiece.

Doctor Mandeep Mehra of Brigham and Women’s Hospital in Boston says the woman was not exactly the picture of good health.

“The diagnosis that I believe is operative here is an underactive thyroid gland or hypothyroidism,” reveals Dr. Mehra.

He points to the woman’s lack of eyebrows, receding hair line, puffy neck and swollen glands.

“That’s the thing about the Mona Lisa, is that Leonardo da Vinci was an uncanny artist who depicted accuracy like no one else. He was an anatomist.”

The doctor says he did take into consideration the lifestyle and dietary patterns of people at that time, which was the early 1500’s.