A pharmacist explains how it’s absorbed and if it really works.

Magnesium spray is a product that is applied externally on the skin. Though it is touted to promote muscle relaxation, improve sleep, and manage migraines, studies of its effectiveness have yielded mixed results.

The following article covers the benefits of magnesium spray, its uses, and its safety considerations.

What Is Magnesium Spray?

Magnesium is a mineral that plays an important role in many of the body’s processes.

It is essential for the following:¹

• DNA and RNA production (two types of nucleic acids that store genetic information)
• Protein production
• Muscle contraction
• Blood pressure regulation
• Blood sugar regulation
• Nerve transmission

Although there is no recommendation for topical usage of magnesium, major health institutions have established a recommended amount of magnesium taken by mouth per day.

Listed below are the recommended daily amount (in milligrams, or mg) of magnesium intake based on age and other factors.²

• 51 years old and above: 420 mg (male), 320 mg (female)
• 31 to 50 years old: 420 mg (male), 320 mg (female or lactating), 360 mg (pregnant)
• 19 to 30 years old: 400 mg (male), 310 mg (female or lactating), 350 mg (pregnant)
• 14 to 18 years old: 410 mg (male), 360 mg (female or lactating), 400 mg (pregnant)

Magnesium spray is a liquid form of magnesium that is applied to the skin. It has been marketed for promoting muscle relaxation and sleep.

Because magnesium chloride hexahydrate is water soluble, it typically takes the form of a spray.

When to See a Healthcare Provider About Muscle Pain

Though self-care is appropriate for muscle pain from minor injuries or exercise, see your healthcare provider if you have severe muscle pain.

Magnesium Spray Benefits

Though taking magnesium supplements by mouth is common, limited research exists on the use of magnesium on the skin to improve magnesium levels in the body.

The thinking there is that magnesium topically applied on the skin bypasses gut absorption.

However, studies comparing the absorption of magnesium taken by mouth as opposed to applied on the skin are lacking.

Despite this scarcity, some studies look at the localized effect of magnesium spray in improving a sore throat after surgery and nerve, muscle, and joint pain.

Intubation-Related Sore Throat

Compared to a placebo (an inactive substance), topical magnesium reduced sore throat severity after surgery in people undergoing tracheal intubation (a procedure for opening up the airway).³ However, further studies are necessary to clarify the optimal dose of topical magnesium.

Nerve Pain

Peripheral neuropathy is nerve damage that causes a tingling and numbing sensation in the arms or legs.

In a study of 20 participants with chronic kidney disease, the daily application of magnesium chloride sprays to limbs affected by peripheral neuropathy for 12 weeks decreased the frequency and severity of nerve pain symptoms. One limitation of the study was that it was performed mostly in females.⁴

Chronic Muscle and Joint Pain

A small-scale study assessed whether applying magnesium to the skin would improve the quality of life of 40 female participants with fibromyalgia. This chronic condition causes muscle and joint pain, fatigue, and other symptoms. The study suggested that four sprays of magnesium chloride solution twice daily to the upper and lower limbs for four weeks may benefit those with fibromyalgia. However, further dose-finding studies with larger sample sizes are necessary to confirm this result.⁵

Does Magnesium Spray Increase Magnesium Levels?

Currently, little research shows that topical magnesium impacts serum magnesium levels.

Magnesium is transported into the cell via magnesium transporters. Because the outer layer of the skin does not contain magnesium transporters, magnesium absorption occurs in the small areas of the sweat glands and hair follicles.¹

One study proposed that applying magnesium to the skin can help with magnesium deficiency within four to six weeks versus four to 12 months in the case of magnesium supplementation by mouth. However, this doesn’t support evidence due to unpublished data.¹

A small-scale human study suggested that 56 mg of magnesium cream applied daily on the skin for 14 days had no statistically significant effect on magnesium blood levels. Although the results were statistically insignificant (meaning they may have been caused by chance), a clinically relevant increase in magnesium blood levels was observed.⁶

From a clinical point of view, clinical usefulness is more relevant than statistical significance because, in this case, such an increase would take months to show change with magnesium supplementation taken by mouth.

It is also important to note that the study’s author declared a beneficial interest in transdermal (via the skin) magnesium cream products.

Because it remains unclear if magnesium absorption via your skin is more effective than by mouth, further studies are necessary to confirm the amount of magnesium absorbed into the skin.

How to Use Magnesium Spray

In one study, magnesium chloride solution was given in a spray bottle and used as follows:⁵

• Spray the solution into the palm and apply evenly on the affected area.
• Wait for four hours between doses.
• Wait at least one hour after application before showering or washing the product off.
• Leave the product on the skin throughout the day and wash it off before bedtime to avoid transferring it to the bed sheets.
• Rinse the solution off with water if your skin becomes irritated.
• Avoid applying the solution to open wounds.

Precautions

Avoid magnesium chloride sprays if you’re allergic to them or their components. Seek immediate medical attention if you have a severe allergic reaction to them (such as itching, hives, or shortness of breath).

Other than skin irritation, topically applied magnesium chloride solution has no known side effects.⁵

Summary

Some studies have shown that the topical use of magnesium sprays can reduce the incidence and severity of an intubation-related sore throat after surgery, decrease the frequency and severity of nerve pain symptoms (peripheral neuropathy), and improve chronic muscle and joint pain (fibromyalgia).

However, larger studies of various populations are necessary to clarify the optimal dose for each of the aforementioned conditions.

More research is also necessary to determine how the use of topical magnesium affects magnesium blood levels.

Sources:

1. Gröber U, Werner T, Vormann J, Kisters K. Myth or reality—transdermal magnesium? Nutrients. 2017;9(8):813. Published 2017 Jul 28. doi:10.3390/nu9080813
2. National Institutes of Health Office of Dietary Supplements. Magnesium.
3. Kuriyama A, Maeda H, Sun R. Topical application of magnesium to prevent intubation-related sore throat in adult surgical patients: a systematic review and meta-analysis. Can J Anaesth. 2019;66(9):1082-1094. doi:10.1007/s12630-019-01396-7
4. Athavale A, Miles N, Pais R, et al. Transdermal magnesium for the treatment of peripheral neuropathy in chronic kidney disease: a single-arm, open-label pilot study. J Palliat Med. 2023;26(12):1654-1661. doi:10.1089/jpm.2023.0229
5. Engen DJ, McAllister SJ, Whipple MO, et al. Effects of transdermal magnesium chloride on quality of life for patients with fibromyalgia: a feasibility study. J Integr Med. 2015;13(5):306-313. doi:10.1016/S2095-4964(15)60195-9
6. Kass L, Rosanoff A, Tanner A, et al. Effect of transdermal magnesium cream on serum and urinary magnesium levels in humans: a pilot study. PLoS One. 2017;12(4):e0174817. Published 2017 Apr 12. doi:10.1371/journal.pone.0174817

Important Notice: This article was originally published at www.verywellhealth.com by Trang Tran, PharmD where all credits are due. Medically reviewed by Allison Herries, RDN

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