Retinoids-Retinal, retinol, and any other derivatives of any structurally similar natural or synthetically produced compound. Some derivatives of retinal or retinol do not have vitmain A activity. However, in the clinical setting, they are sometimes used for other purposes, such as treating skin disorders.

Retinoic acid, for example, is probably the form of vitamin A that helps in bone growth and functional integrity of epithelial cells, as discussed. Chemically related, however, are structurally similar forms of retinoic acid. These forms are called 1) tretinoin (the all-trans isomer) and 2) isotretinoin (the 13-cis isomer). Don't let the technical terms frighten you. These "isomer" terms just help to describe the exact shape of the molecule. These forms of retinoic acid are used to treat acne and other skin disorders. Although they can be quite effective, they also come with their risks. Excessive exposure to sunlight and other forms of UV light (tanning salons, etc) can increase the risk of skin cancer. This drug also cannot be used during pregnancy because of the risk of harmful side effects to the unborn child.