retinoid

1. Resembling a resin; resinous. [G. retine, resin, + eidos, resemblance] 2. Resembling the retina. [Mediev. L. retina] 3. In plural form, term used to describe the natural forms and synthetic analogs of retinol.

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ret·i·noid 'ret-ən-.ȯid n any of various synthetic or naturally occurring analogs of vitamin A

retinoid adj

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n.

any one of a group of drugs derived from vitamin A. They bind to one or more of six specific receptors that are found on many cells. On the skin they act to cause drying and peeling and a reduction in oil (sebum) production. These effects can be useful in the treatment of severe acne, psoriasis, ichthyosis, and other skin disorders. Retinoids include isotretinoin, tretinoin, acitretin, and tazarotene; they are administered by mouth or applied as a cream. Possible side-effects, which may be serious, include severe fetal abnormalities (if taken by pregnant women), toxic effects on babies (if taken by breastfeeding mothers), liver and kidney damage, excessive drying, redness and itching of the skin, and muscle pain and stiffness.

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ret·i·noid (retґĭ-noid) 1. resembling the retina. 2. retinol, retinal, or any structurally similar natural derivative or synthetic compound; the latter need any not have vitamin A activity.