Lunula – a small crescent at the base of the nail – can “inform” about a person's health with its shape and color, says dermatologist Grigory Goldin.
The medic told the MedicForum portal that the word “lunula” comes from the Latin lunula, “little moon.” This term refers to the milky-white “crescent” located at the bottom of the nail plate.
“The lunula is the visible part of the nail matrix that shines through in this place and therefore appears white. If you didn't find it right away, move the cuticle back very carefully – the lunula may be hiding under it. Under certain circumstances, the lunula may disappear completely, but it is also able to recover and become visible again,” Goldin said.
Why is it needed?The lunula has no direct function, but it is part of the nail matrix, which in turn is responsible for nail growth. Here, new skin cells are constantly being created that form keratin. When cells die, this obsolete material is pushed out by new cells. We perceive it as the growth of nails.
What does the lunula say about health?According to traditional Chinese medicine, if a person has fewer than eight holes on ten fingers, it can be a sign of insufficient blood circulation in the body, a sluggish metabolism, and general poor health. But the whiter the lunula, the more energetic and healthy the body.
According to Goldin, a change in the color of the lunula can indeed be an indicator of adverse changes.
Nail holes can “speak” about heart problems and hypertension
“If the crescent on the nails becomes red, possible heart problems.
What else? The size of the lunula – usually it takes up about a fifth of the nail. If less, it may be a sign of insufficient, too weak blood circulation. Too large, in turn, may indicate that the body is working with excessive zeal, and it will not be superfluous to check for hyperthyroidism. portal MedikForum.ru wrote about what may be hiding behind the appearance of dandruff on the eyebrows. 
Grigory Goldin Health dermatocosmetologist, dermatosurgeon