Magnesium Sulfate
Magnesium sulfate is the magnesium salt known as Epsom salt. As a medicine it is labeled as a saline laxative for occasional constipation.
What supports oral use for constipation?
The DailyMed label lists relief of occasional constipation and a typical bowel movement within half an hour to six hours. This is a medicinal use with its own directions and warnings, not evidence for routine daily supplementation. 1
What did the mineral-water trial find?
A four-week French trial enrolled 244 women aged 18–60 with functional constipation. At week two, constipation improved in 37.5% drinking one liter daily of magnesium sulfate-rich Hépar water versus 21.1% drinking low-mineral water. The lower-water-dose group did not differ significantly from control. This result concerns a specific mineral water, not a homemade Epsom-salt solution. 2
A specific mineral water helped at the higher studied amount; the finding does not establish equivalent effects for every sulfate product. 2
Can a bath raise magnesium levels?
A 2017 review found the evidence for transdermal magnesium, meaning delivery through the skin, inadequate. Available bath and skin studies did not establish a reliable way to replace oral magnesium for deficiency. 3
The review includes a small two-week magnesium-cream pilot: serum magnesium rose slightly, but the overall change was not statistically significant; significance appeared only in a subgroup of non-athletes. This preliminary signal leaves absorption questions open and is not an Epsom-salt bath trial. 3
What about recovery or better sleep?
The transdermal review does not establish that magnesium entering through a bath improves sleep or muscle recovery. A claim that soaking delivers a therapeutic magnesium dose needs evidence beyond the fact that the bath contains magnesium. 3
The reviewed skin-delivery evidence does not establish a magnesium-specific recovery benefit. 3
Effects by health goal
Open an effect to see the studies behind its rating. Bars show the size of the effect; the letter grades the evidence.
Gut Health1 effect
No study is linked to this rating.
Sleep1 effect
No study is linked to this rating.
Essential Health1 effect
No study is linked to this rating.
Longevity1 effect
No study is linked to this rating.
Cardiovascular1 effect
No study is linked to this rating.
Weight Management1 effect
No study is linked to this rating.
Bone & Joint1 effect
No study is linked to this rating.
Fitness1 effect
No study is linked to this rating.
All studies
3 publications are linked to Magnesium Sulfate, newest first.