The deficiency that causes dark eyelids are iron deficiencies as well as vitamin B12 deficiencies and vitamin K deficiencies which all can contribute to the appearance of dark eyelids and dark circles including under the eyes.
Although the vitamin and iron deficiencies are not always the cause or sole cause of dark eyelids or dark circles.
Other factors that can result in and cause dark eyelids or dark circles under the eyes are genetics, sleep deprivation, allergies and sun exposure.
Even overproduction of melanin can cause dark eyelids.
Melanin is a pigment which gives your skin it's color and excessive production of melanin in the eyelids can result in darkening of the eyelids.
Overproduction of melanin can be triggered by trauma, inflammation or sun exposure and some people are also genetically predisposed to hyperpigmentation around their eyes.
Thinning skin and visible blood vessels can also contribute to dark eyelids.
The skin around your eyes is very thin and as you age, the skin can become even thinner and the thinning of the skin can make the underlying blood vessels become more visible and cause a dark or bluish tint.
And reduced collagen and even reduced elastic, which naturally also things as you age, can also lead to the dark eyelids.
Low iron levels can result in reduced oxygen in your blood and cause melanin to overproduce and make your skin look darker including your eyelids.
And lack of sleep can worsen the appearance of dark circles and dark eyelids and make them look even more pronounced.