D vitamin - created under the influence of ultraviolet radiation on the skin, stimulates the uptake of calcium and phosphorus and bone mineralization.

Dandruff - a result of skin cell keratinization violations.

Decoction - water solution from the leaves, flowers and herbs, heated for 30-40 minutes on water bath (when a container with decoction is immersed and heated in a pot with boiling water).

Dehydroacetic acid - is an organic compound, classified as a pyrone derivative and used mostly as a fungicide and bactericide.

Dermis - the intermediate layer of the skin.

Dermatitis - an inflammatory skin disease.

Detergent - synthetic cleanser with antibacterial properties; may be in solid and liquid form, i.e. soaps and shampoos.

Dextran - a high molecular weight glucose polymer produced by the action of the Leuconostoc Mesenteroides bacteria on a sucrose substrate. It is a polysaccharide with water-binding properties for skin and hair. In cosmetic products functions as a skin and hair conditioning agent.  

Dihydrotesterone (DHT or 5α-DHT) - is an androgen, synthesized primarily in the prostate gland, testes, hair follicles, and adrenal glands by the enzyme 5α-reductase by means of reducing the 4,5 double-bond of the hormone testosterone. Approximately 5% of serum testosterone produced in men undergoes 5α-reduction to form the more potent androgen, dihydrotestesterone. DHT has three times greater affinity for androgen receptors than testosterone and has 15-30 times greater affifinty than adrenal androgens. During embryogenesis DHT has an essential role in the formation of the male external genitalia, and in the adult DHT acts as the primary androgen in the prostate and hair follicles. DHT is the primary contributing factor in male pattern baldness. However, female hair loss is more complex, and DHT is only one of several possible causes. Women with increased levels of DHT may develop certain androgynous male secondary sex characteristics, including a deepened voice and facial hair.

Dithranol - or Anthralin is a Hydroxyanthrone, anthracene derivative, medicine applied to the skin of people with psoriasis. It is available as creams, ointment or pastes in 0.1 to 2% strengths.