Last update Aug. 31, 2020

Magnesium Hydroxide

Very Low Risk

Safe. Compatible. Minimal risk for breastfeeding and infant.

Various magnesium salts, such as carbonate, hydroxide, oxide, peroxide, silicate and trisilicate are used as antacids; carbonate, citrate, hydroxide, oxide, peroxide and sulphate as osmotic laxatives and aspartate, citrate, chloride, gluconate, hydroxide, lactate, levulinate, orotate, oxide, pidolate and sulphate) are used as mineral supplements in the form of oral dietary intake or intramuscularly in magnesium deficiency states.
It is also authorized as a food additive (E-528) with stabilizing functions and acidity regulation.

Daily magnesium requirements for breastfeeding mothers are estimated at 310 to 360 mg (MedlinePlus 2017); some countries have established figures of up to 450 mg daily (Hall 2010).

Since the last update we have not found any published data on its excretion in breast milk.

Magnesium is a natural component of milk. The average natural concentration of magnesium in milk is 31 mg/L (15 to 64 mg/L) (Dórea 2000, Feeley 1983).

When ingested, magnesium does not concentrate in breastmilk. Its concentration in milk is very stable and depends little on diet (USD 2000) and other factors, including intravenous administration of magnesium sulphate to the mother: the levels of magnesium in milk of mothers treated with intravenous magnesium sulphate increased in clinically non-significant amounts in relation to mothers not in treatment (Cruikshank 1982, Dorea 2000).

Its low oral bioavailability (AEMPS 2017, Morris 1987) hinders transfer to plasma and, therefore, to breastmilk, as well as transfer to infant plasma via breastmilk.

If the intravenous administration of magnesium sulphate is considered compatible with breastfeeding, all the more reason that salts administered orally will also be compatible (Hagemann 1998).

Various medical associations and expert consensus consider the use of various magnesium salts to be safe during breastfeeding (Hale 2019, Briggs 2015, Dennis 2012, Schaefer 2007, Mahadevan 2006, Richter 2005, Nice 2000, Broussard 1998, Idama 1998).
The manufacturer considers the use of magnesium lactate to be safe during breastfeeding (AEMPS-LAINCO 2017).
List of WHO essential medicines: compatible with breastfeeding (WHO / UNICEF 2002).


We do not have alternatives for Magnesium Hydroxide since it is relatively safe.

Suggestions made at e-lactancia are done by APILAM team, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Magnesium Hydroxide in other languages or writings:


Main tradenames from several countries containing Magnesium Hydroxide in its composition:


Variable Value Unit
Oral Bioavail. 15 - 30 %
Molecular weight 58 daltons
Protein Binding 33 %

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