How to take a magnesium bath

Warm water, a measured amount of magnesium salts and about twenty minutes. Here is how to run one, how much to use and what to expect from the water.

Join the waitlist

A lavender bath bomb tile beside its closed matte black box, the Lavender Hush label on the lid — Lavender Hush, 200 g, beside its box.

98–102 °FWater temperature (37–39 °C)

20 minA good length for a soak

65 gMagnesium salts in one Twelve Bath tile

What a magnesium bath is

A magnesium bath is an ordinary warm bath with magnesium salts dissolved in it. Two salts are used: magnesium sulfate, sold as Epsom salt, and magnesium chloride, sold as flakes. Both dissolve completely, and the water stays clear or very slightly cloudy.

Magnesium salts have long been used in baths. This guide is about running one well. We don't make health claims about what magnesium does.

How to run one, step by step

Fill the tub first. Run it to 98–102 °F (37–39 °C). Check with your wrist or a bath thermometer.
Add the salts. Pour Epsom salt or flakes under the tap for the last minute of filling, or drop in a bath bomb once the tap is off.
Stir with your hand until nothing is left on the bottom. Flakes take a minute or two; Epsom salt a few minutes.
Soak for about 20 minutes. Top up with warm water if it cools.
Step out slowly and rinse off if your skin feels salty.
Drain the tub and run the warm tap for a few seconds.

How much magnesium salt to use

Follow the directions on the package; they differ by brand and by salt. For scale, a typical filled bath holds roughly 100–150 L (26–40 US gallons) of water.

One Twelve Bath tile65 g

One tile and a Deep Soak sachet245 g

One tile in 120 L of waterabout 0.5 g per litre

Tile and Deep Soak in 120 Labout 2 g per litre

Flakes, Epsom salt or a bath bomb

Epsom salt (magnesium sulfate) is the cheapest per gram and the easiest to find. Magnesium chloride flakes make the water feel silkier, and they need to stay sealed, because they draw moisture from the air. The two are compared in Epsom salt or magnesium chloride.

A bath bomb adds fizz and scent and does the measuring for you, though many don't say how much magnesium is inside. Ours is a pressed tile with 65 g of magnesium chloride flakes, printed on every label.

Before you get in

Pregnant, or have a medical condition? Ask your doctor first.
Skip it on broken or freshly shaved skin, where salt stings.
For children 3 and over, choose an unscented salt or bomb and keep the water warm, not hot.
The tub can get slippery. Hold the side as you get out.