You can make a simple magnesium lotion by dissolving Epsom salt in hot water to create a concentrated brine, then blending it into a basic lotion base with an emulsifier and a carrier oil. The whole process takes about 20 minutes, and the result is a smooth, spreadable cream you can apply daily. Here’s how to do it right, with the ratios that actually work.
What You Need
The ingredient list is short, but each component matters. You’ll need:
- Epsom salt (magnesium sulfate): 1/2 cup
- Distilled water: 1/3 cup
- Carrier oil: 1/4 cup (coconut oil, sweet almond oil, or shea butter all work)
- Emulsifying wax: 1 tablespoon
- Optional preservative: grapefruit seed extract or another broad-spectrum cosmetic preservative
Use distilled water, not tap. Tap water introduces minerals and microorganisms that shorten shelf life and can interfere with how well the Epsom salt dissolves. Epsom salt dissolves readily in water at about 71 grams per 100 ml at room temperature, so the ratio above keeps you well within that solubility limit and avoids gritty crystals reforming as the lotion cools.
Why Emulsifying Wax Matters
This is where most DIY recipes go wrong. Dissolved Epsom salt is an electrolyte, and electrolytes destabilize many common thickeners and emulsifiers. Polymer-based thickeners (the kind found in some commercial lotions) are particularly sensitive to salts and will break down, leaving you with a separated, watery mess.
Non-ionic emulsifying wax is the most reliable choice. It carries no electrical charge, so it tolerates the dissolved minerals without separating. You can find it online or at soap-making supply stores, usually labeled simply as “emulsifying wax NF.” Beeswax alone won’t hold the water and oil phases together in the presence of this much dissolved salt. If you want to use beeswax for texture, combine it with a small amount of emulsifying wax rather than relying on it as your sole emulsifier.
Step-by-Step Instructions
Make the Magnesium Brine
Heat 1/3 cup of distilled water until it’s just below boiling. Pour it over 1/2 cup of Epsom salt in a heat-safe glass container and stir until the crystals fully dissolve. This takes about two minutes. The solution will look completely clear when it’s ready. Set it aside to cool to roughly body temperature.
Prepare the Oil Phase
In a separate container, combine 1/4 cup of your carrier oil with 1 tablespoon of emulsifying wax. Gently heat this in a double boiler or microwave in short bursts until the wax melts completely into the oil. If you’re using coconut oil or shea butter, they’ll melt together with the wax into a smooth liquid.
Combine and Blend
With both phases warm but not hot (aiming for around 120°F or so), slowly pour the magnesium brine into the oil and wax mixture while stirring constantly. An immersion blender works best here. Blend for two to three minutes until the mixture turns opaque and thickens into a creamy consistency. It will continue to thicken as it cools.
If you’re adding a preservative, stir it in once the mixture has cooled below 104°F (40°C), since heat can deactivate it. Transfer the finished lotion into a clean glass jar or pump bottle.
Shelf Life and Storage
Any lotion that contains water is a potential breeding ground for bacteria. Without a preservative, homemade water-based lotions last roughly three days at room temperature. With a broad-spectrum preservative like grapefruit seed extract or a cosmetic-grade option such as Optiphen, that window extends to one to three months.
Store your lotion in the refrigerator to slow microbial growth, and always use clean hands or a small spatula to scoop it out. If the lotion changes color, develops an off smell, or separates significantly, discard it. Making smaller batches more frequently is the simplest way to avoid waste and keep the product fresh.
Is Epsom Salt Safe on Skin?
Magnesium sulfate has a strong safety profile for topical use. The Cosmetic Ingredient Review Expert Panel assessed it and concluded it is safe in cosmetics at concentrations up to 11% in leave-on products and 25% in rinse-off products. Even at 50% concentration, magnesium sulfate tested negative for skin irritation in animal studies and showed no potential to cause allergic sensitization in patch testing.
The recipe above produces a lotion in the range of roughly 8 to 10% magnesium sulfate after blending with oil and wax, which is comfortably within that safe range for daily leave-on use. If you have very sensitive or broken skin, test a small amount on the inside of your wrist first and wait 24 hours before applying it more broadly.
Does Magnesium Absorb Through Skin?
This is the part that generates the most debate. A pilot study published in PLOS One tested a magnesium cream delivering 56 mg of magnesium per day over two weeks. The group using the magnesium cream showed an 8.5% increase in blood magnesium levels and a 9.1% increase in urinary magnesium, while the placebo group saw minimal changes. In non-athletes specifically, the increase was more pronounced: a 22.7% rise in blood magnesium that reached statistical significance.
That said, 56 mg is a modest dose compared to what oral supplements deliver, and this was a small study. Transdermal magnesium likely contributes some absorption, but it’s not a reliable replacement for dietary intake or supplements if you’ve been told you’re deficient. Think of it as a complement, not a primary source. Many people use magnesium lotion mainly for localized comfort on sore muscles and joints, and the direct contact with skin in those areas may be where it feels most useful.
Epsom Salt vs. Magnesium Chloride
Most commercial “magnesium oil” products use magnesium chloride flakes, not Epsom salt. The two are different compounds. Epsom salt is magnesium sulfate, which dissolves well but has a lower percentage of elemental magnesium by weight (about 10%) compared to magnesium chloride (about 12%). Magnesium chloride also produces a more concentrated brine and is the form used in most of the transdermal absorption research.
Epsom salt works fine for a lotion, but the resulting product will contain somewhat less elemental magnesium per teaspoon than one made with magnesium chloride. If absorption is your primary goal, magnesium chloride flakes may be worth considering. If you’re mainly after a soothing topical product for tired muscles, Epsom salt does the job at a fraction of the cost.
Troubleshooting Common Problems
If your lotion is grainy, the Epsom salt didn’t fully dissolve before you combined the phases. Reheat the brine gently and stir until clear before trying again. If the lotion separates into a watery layer and an oily layer within hours, your emulsifier likely wasn’t sufficient. Add another half tablespoon of emulsifying wax, remelt everything gently in a double boiler, and reblend. Separation can also happen if you combined the two phases at very different temperatures, so keeping them within about 10 degrees of each other when mixing helps.
If the lotion feels too thick, add distilled water a teaspoon at a time and blend until you reach your preferred consistency. If it’s too thin, let it cool completely before judging. Most emulsified lotions thicken considerably as they reach room temperature. You can also increase the emulsifying wax slightly in your next batch for a firmer body.