C₃H₈O₃

Glycerin or glycerol is an osmotic dehydrating agent with hygroscopic and lubricating properties. It increases plasma osmolality, which facilitates the movement of water by osmosis from extravascular spaces into the plasma. It is used orally to reduce intraocular pressure before eye surgery and in the treatment of acute glaucoma. It is also used topically in the eye. Orally or intravenously it is used to reduce intracranial pressure and rectally as a laxative (osmotic and lubricant) in the treatment of constipation. Glycerol is available as an emollient or lubricant in many pharmaceutical preparations ^{(Nice 2000)}. Topical (ocular, otic, cutaneous), oral, intravenous and rectal administration.

At the date of the last update we found no published data on its excretion in breast milk.

Glycerol or glycerine is a normal constituent of human tissues. It is involved in lipid and galactose synthesis and is metabolised to glucose or glycogen. It is found naturally in breast milk, with higher concentration in colostrum. ^{(Mohammad 2015 and 2014, Jóźwik 2013, Sunehag 2002)}

Used as a laxative rectally, it has little or no absorption.

It has been used as a laxative in preterm infants. ^{(Isayama 2019, Dutta 2015, Mena 204)}

Oral or intravenous administration is rarely used (extracellular oedema, intracranial hypertension, diagnosis of Ménière's disease). Its short half-life makes it compatible with breastfeeding in these rare cases.

Ophthalmic administration is also compatible.

It has been used in creams and gels to treat nipple soreness and cracks during breastfeeding without clear efficacy ^{(de Barros 2019, Dennis 2014, Morland 2005, Cadwell 2004)}. It should be thoroughly flushed with water before feeding to prevent the infant from taking it, as its high intestinal absorption could lead to increased plasma osmolarity and dehydration in the infant.