Magnesium oil, a concentrated solution of magnesium chloride in water, has become increasingly popular for topical application, particularly to the feet. Whilst magnesium is essential for muscle function, nerve transmission and energy production, the benefits of magnesium oil on feet remain largely anecdotal. The skin acts as a protective barrier, limiting absorption of charged ions like magnesium, and the feet's thicker outer layer may further reduce penetration. This article examines the claimed benefits, proper application methods, safety considerations and the current scientific evidence surrounding transdermal magnesium absorption to help you make informed decisions about this complementary approach.

What Is Magnesium Oil and How Does It Work?

Magnesium oil is not actually an oil but rather a concentrated solution of magnesium chloride dissolved in water. When applied to the skin, it has an oily texture, hence the name. This topical preparation has gained popularity as an alternative method of magnesium application, though it's important to note that such products are not licensed medicines in the UK for treating magnesium deficiency.

Magnesium is an essential mineral involved in over 300 enzymatic reactions in the body. It plays crucial roles in muscle function, nerve transmission, energy production, and bone health. The body cannot produce magnesium, so it must be obtained through diet or supplementation. Common dietary sources include green leafy vegetables, nuts, seeds, and whole grains.

Proponents suggest that magnesium oil works through transdermal absorption — the passage of magnesium ions through the skin. However, this mechanism remains largely theoretical. The skin's primary function is to act as a protective barrier, and the stratum corneum (outermost layer) significantly limits penetration of charged ions like magnesium. The feet, with their thicker stratum corneum, are actually less permeable than many other body areas.

While some users apply magnesium oil to feet based on personal preference, there is no robust clinical evidence demonstrating that this site offers superior absorption or effectiveness. Any benefits experienced may be due to local effects at the application site rather than significant systemic absorption into the bloodstream.

Benefits of Applying Magnesium Oil to Feet

Advocates of magnesium oil application to the feet claim several potential benefits, though it is essential to recognise that evidence supporting these claims varies considerably in quality and strength.

Muscle relaxation and cramp relief are among the most commonly cited anecdotal benefits. Magnesium plays a vital role in muscle contraction and relaxation, and deficiency has been associated with muscle cramps and spasms. Some users report that applying magnesium oil to their feet before bed helps reduce nocturnal leg cramps, though there is no definitive link established through large-scale clinical trials. It's worth noting that NICE Clinical Knowledge Summaries do not routinely recommend magnesium (even oral) for idiopathic leg cramps in adults.

Improved sleep quality is another frequently mentioned benefit. Some individuals find that topical magnesium application as part of their bedtime routine contributes to better sleep, though this may also be influenced by the relaxing ritual itself rather than magnesium absorption.

Stress reduction and relaxation are also reported by some users. The massaging action during application may provide comfort and physical relaxation of foot muscles.

Additionally, some users apply magnesium oil to address localised foot discomfort, including tired, aching feet after prolonged standing or exercise.

It is important to emphasise that whilst anecdotal reports are positive, high-quality clinical evidence specifically examining magnesium oil application to feet remains limited. Individual responses may vary considerably.

If you experience persistent, severe or painful cramps, cramps with swelling/redness/warmth, or neurological symptoms, you should seek assessment from your GP. Pregnant women experiencing cramps should consult their midwife or GP.

How to Use Magnesium Oil on Feet Safely

If you wish to try magnesium oil on your feet, following proper application techniques can help maximise potential benefits whilst minimising adverse effects.

Preparation and application:

• Wash and thoroughly dry your feet before application

• Follow the manufacturer's instructions regarding amount and application method

• Start with a small amount to test your skin's reaction

• Massage gently into the soles and tops of feet

• Allow the solution to remain on the skin according to product instructions

• Some people prefer to apply magnesium oil before bed and wear cotton socks, though be aware that occlusion may increase irritation for some individuals

Important safety considerations:

• Avoid application to broken, irritated or ulcerated skin

• Keep away from eyes and mucous membranes

• Wash hands thoroughly after application

• Discontinue use if significant irritation occurs

• Keep out of reach of children

• People with diabetes or peripheral neuropathy should consult a healthcare professional before using new topical products on their feet

Frequency of use: Start with less frequent application (perhaps 2-3 times per week) to assess tolerance, particularly if you have sensitive skin.

Dilution for sensitive skin: If you experience tingling, itching, or irritation, dilute the magnesium oil with an equal part of water or apply a moisturiser after the magnesium has been absorbed. Some commercial preparations are already diluted to reduce skin sensitivity.

Patch testing: Before widespread use, perform a patch test by applying a small amount to a limited area of skin and waiting 24 hours to check for adverse reactions.

Storage: Keep magnesium oil in a cool, dry place away from direct sunlight. Most preparations remain stable for 12–24 months when stored properly.

If you are considering magnesium supplementation for a specific health condition, consult your GP or a registered healthcare professional to discuss whether dietary changes or oral supplementation might be more appropriate for your circumstances.

Potential Side Effects and Who Should Avoid It

Whilst topical magnesium oil is generally considered safe for most people, some individuals may experience adverse effects or should exercise caution before use.

Common side effects include:

• Skin irritation: Tingling, itching, or a burning sensation at the application site is the most frequently reported side effect. This typically occurs due to the high concentration of magnesium chloride and usually diminishes with continued use or dilution

• Dryness or rash: Some individuals develop dry, flaky skin or a mild rash where the magnesium oil has been applied

• Stinging on broken skin: Application to areas with cuts, abrasions, or broken skin can cause significant stinging and should be avoided

Who should exercise caution or avoid use:

Individuals with kidney disease should consult their doctor before using magnesium oil. While systemic absorption through intact skin appears minimal, those with moderate to severe renal impairment should seek medical advice before use.

People with skin conditions such as eczema, psoriasis, or dermatitis should seek medical advice before use, as magnesium oil may exacerbate these conditions or cause additional irritation.

Pregnant or breastfeeding women should discuss magnesium supplementation with their midwife or GP to ensure appropriate safety.

Those taking regular medications may wish to consult their pharmacist or GP before use. While topical magnesium is unlikely to cause clinically significant interactions (unlike oral magnesium supplements), it's prudent to seek advice if you're on critical medicines.

If you experience persistent skin irritation or a rash after using magnesium oil, discontinue use and rinse the area thoroughly. For severe burning, blistering or dermatitis, rinse off immediately and seek medical advice. If you develop difficulty breathing, swelling of the face/mouth/throat, or other signs of severe allergic reaction, call 999 or attend A&E immediately.

You can report any suspected side effects to the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk or via the Yellow Card app.

Evidence Behind Transdermal Magnesium Absorption

The scientific evidence regarding transdermal magnesium absorption remains limited and somewhat controversial within the medical community. Understanding the current state of research is important for making informed decisions about magnesium oil use.

Limited clinical evidence: A small number of studies have investigated transdermal magnesium absorption, with mixed results. One frequently cited pilot study published in 2010 suggested that magnesium levels increased following topical application, but this study had significant methodological limitations, including a small sample size and lack of a control group. Subsequent research has not consistently replicated these findings.

Skin barrier challenges: The skin's stratum corneum is specifically designed to prevent the passage of substances, including minerals and electrolytes. Magnesium ions are charged particles (cations) that typically have difficulty penetrating this lipid-rich barrier. Whilst some small molecules can pass through the skin, the extent to which magnesium chloride can achieve clinically significant systemic absorption remains uncertain.

Lack of robust trials: There is currently no large-scale, randomised controlled trial published in peer-reviewed literature that definitively demonstrates clinically significant increases in serum magnesium levels following topical application. Most evidence is anecdotal or based on small, poorly controlled studies.

UK guidance position: Neither NICE nor NHS guidance currently recommends transdermal magnesium for treating magnesium deficiency. The NHS and British National Formulary (BNF) indicate that oral supplementation remains the evidence-based first-line approach for addressing confirmed deficiency, with intravenous administration reserved for severe cases in hospital settings.

Possible local effects: Even if systemic absorption is minimal, there may be local effects at the application site. Magnesium could potentially influence local muscle relaxation or have other localised benefits, though this hypothesis requires further investigation.

For individuals concerned about magnesium deficiency (symptoms may include muscle cramps, fatigue, or irregular heartbeat), consult your GP for appropriate testing of serum magnesium levels and evidence-based treatment recommendations. Avoid non-validated tests such as hair mineral analysis for assessing magnesium status.

Frequently Asked Questions