Retinoid

[4] The biology of retinoids is complex, having well-documented effectiveness in the management of conditions ranging from acute promyelocytic leukemia to acne to photoaging.

The conjugated system formed by alternating C=C double bonds in the polyene side chain are responsible for the color of retinoids (typically yellow, orange, or red).

A medical sign of chronic or acute poisoning with retinol is hypervitaminosis A, which includes the presence of painful tender swellings on the long bones.

Anorexia, skin lesions, hair loss, hepatosplenomegaly, papilloedema, bleeding, general malaise, pseudotumor cerebri, and death may also occur.

Large-scale randomized, controlled clinical trials have conclusively shown that vitamin A, retinol and other retinoids increase mortality and cancer rates.

[32] The Pharmacovigilance Risk Assessment Committee (PRAC), based on its review, confirmed that taking oral retinoids during pregnancy can have harmful effects on the baby as they may cause CNS, cranio-facial, cardiovascular and other defects.

[citation needed] Many lotions that claim to prevent or treat stretch marks contain retinol, which is not an ingredient that is safe for pregnant women.

[36][37] The Association of the American Academy of Dermatology (AAD) recommends that pregnant women consult a health care provider before trying any lotions or oils for stretch mark prevention.