Ocean Bathing and Magnesium: Fact or Fiction?

People have used mineral-rich waters in skincare for centuries. This practice is known as balneotherapy or thalassotherapy, which involves using mineral water, seawater, or mud in skin and wellness treatments.[1]

Some research suggests that very mineral-rich waters, especially the Dead Sea, may help support skin comfort. The Dead Sea is much saltier and more mineral-rich than regular ocean water, and contains minerals like magnesium, calcium and bromide. These minerals have been linked with improvements in dry, irritated, flaky, itchy, or inflamed skin in some studies.[5]

However, this does not mean that swimming in the ocean will “top up” your magnesium levels like a supplement would.

The evidence is stronger for local skin benefits than for whole-body magnesium absorption.

Can the ocean boost your magnesium levels?

Not really.

While saltwater and mineral-rich bathing may have benefits for the skin, there is not enough evidence to say that swimming in the ocean can raise your body’s magnesium levels in a meaningful way.

Low magnesium intake is common, with one estimate suggesting around 31% of people globally may not get enough magnesium from their diet.[3] But checking magnesium levels is also tricky, because a standard blood test does not always show how much magnesium is stored inside your cells or tissues.[2]

Some people claim that absorbing magnesium through the skin is better because it “bypasses digestion.” However, the science does not strongly support that. Researchers still do not know whether enough magnesium can pass through the skin during bathing to make a real difference to magnesium deficiency.[6]

So, while the ocean may be good for your skin and overall wellbeing, it should not be seen as a replacement for magnesium-rich foods or oral magnesium supplements when needed.

What can mineral-rich water do for your skin?

Saltwater and mineral-rich water may help support the skin directly.

In one study, people with dry, sensitive skin bathed in a magnesium-rich Dead Sea salt solution. Compared with regular tap water, the mineral-rich bath helped:

• support the skin’s natural barrier
• increase skin hydration
• reduce skin redness, which is often a sign of irritation or inflammation[8]

This suggests that minerals in saltwater may help the outer layers of the skin feel calmer, more hydrated, and better protected. It’s worth noting, the Dead Sea is much saltier and more mineral-rich than normal ocean water, so we cannot assume a regular ocean swim will have the exact same effect.

Scientists think these skin benefits may happen through local ionic effects on the skin. In other words, minerals in the water, including magnesium (Mg²⁺), calcium (Ca²⁺), chloride (Cl⁻), and potassium (K⁺), may interact with the skin’s outer layer, known as the epidermis.

These minerals are involved in skin barrier homeostasis (the skin’s ability to keep moisture in, keep irritants out, and repair its protective outer layer) which may help explain why mineral-rich bathing can support skin comfort and hydration.[5] However, this is different from saying that magnesium is absorbed through the skin in amounts large enough to restore low magnesium levels throughout the body.

Another possible explanation is that very salty water creates a temporary “salt gradient” on the skin.[4] Put simply, when the water outside your skin is much saltier than the water inside the outer skin layers, it can gently pull and shift water around at the skin surface. This may act like a short-term signal to skin cells, influencing how they respond, repair, and maintain the skin barrier.

Scientists have also proposed that this may involve mechanosensitive ion channels, such as Piezo proteins, which help cells sense physical changes like pressure, stretch or fluid movement.[7]

These mechanisms may help explain why mineral-rich bathing can support skin comfort and barrier function. However, they do not prove that regular ocean bathing has the same effect as Dead Sea-style mineral bathing, or that enough magnesium is absorbed through the skin to meaningfully improve whole-body magnesium levels.[6]

What research suggests about magnesium penetration through skin

Magnesium ions have been shown to penetrate into human skin in experimental settings, depending on concentration and exposure time, with research suggesting that hair follicles may act as tiny entry points, helping magnesium move into the skin more easily.[9]

This means some magnesium can pass into the skin under certain conditions, a process known as cutaneous permeation. However, this does not prove that bathing in the ocean, soaking in mineral water, or using topical magnesium can restore low magnesium levels throughout the whole body.[6][9]

A small pilot study using a transdermal magnesium cream reported changes in magnesium measurements, but the evidence is still early and limited. It does not show that magnesium creams, sprays, or baths work as well as (or better than) oral magnesium supplements for correcting magnesium deficiency.[10]

What about magnesium oil?

This is where magnesium oil often enters the conversation. Despite the name, magnesium oil is not actually an oil. It is usually a concentrated magnesium chloride spray, rub, or solution that feels slightly oily on the skin.

Because magnesium ions can pass into the skin under certain conditions, magnesium oil is often marketed as a way to “bypass the gut” or achieve better absorption than oral supplements. However, the evidence does not currently support those stronger claims.

Oral magnesium has a much longer clinical track record for correcting magnesium deficiency. By comparison, evidence that transdermal magnesium (magnesium applied through the skin) can reliably improve whole-body magnesium status is still limited and inconsistent.[11]

So, while magnesium oil may feel soothing for some people, it should not be treated as a proven replacement for magnesium-rich foods or oral magnesium supplements when the goal is correcting deficiency.

The unexpected link: ocean magnesium vs insulin resistance

Interestingly, one study looked at magnesium from the ocean in a very different way. Not through bathing, but by taking it orally.

A 12-week randomised, double-blind trial published in Medicina (Kaunas) tested whether a deep seawater mineral extract containing magnesium (Mg²⁺) could support blood sugar and insulin-related markers in adults with impaired glucose tolerance, which is often used to identify people at increased risk of type 2 diabetes.[12]

Participants took either the deep seawater mineral extract or a placebo every day for 12 weeks. At the end of the study, the group taking the mineral extract showed improvements in several insulin sensitivity and insulin resistance markers, including fasting insulin and calculated insulin-response scores.[12]

However, the study did not find significant differences in some of the main blood sugar markers, such as fasting glucose, post-meal glucose, or HbA1c.[12]

In simple terms, the magnesium-rich deep seawater extract appeared to support how the body responds to insulin, but it did not clearly change standard blood sugar levels over the 12-week period.

This is an important distinction: the study was about oral intake of a concentrated deep seawater mineral extract, not absorbing magnesium through the skin from ocean bathing.

Can ocean bathing replace oral supplementation?

Not if the goal is to correct low magnesium levels.

Saltwater and mineral-rich bathing may support the skin in certain contexts, especially in mineral-rich or hypersaline waters that have been studied clinically, such as Dead Sea-style bathing.[5][8] These benefits appear to be more about local skin effects, such as supporting skin comfort, hydration, and barrier function.

However, this is different from improving whole-body magnesium status. Current evidence does not show that regular ocean bathing provides enough magnesium through the skin to replace magnesium from food or oral supplements.[6]

So, while ocean bathing may be a helpful ritual for skin comfort and general wellbeing, improving magnesium intake is still best approached through magnesium-rich foods and, where appropriate, oral supplementation.

BON CHARGE: This content is for general education and is not medical advice. Our products are not intended to diagnose, treat, cure, or prevent any disease. Always follow product instructions and consult a qualified healthcare professional for guidance tailored to you. Individual results may vary.

References

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2. Workinger JL, Doyle RP, Bortz J. Challenges in the diagnosis of magnesium status. Nutrients. 2018;10(9):1202.
3. Zhang W, Zhao Y. Global dietary magnesium deficiency: prevalence, underlying causes, health consequences, and strategic solutions. Int J Vitam Nutr Res. 2025;95:46828. https://doi.org/10.31083/IJVNR46828
4. Manoharan P, Kaliaperumal K. Salt and skin. Int J Dermatol. 2022;61(3):291–298. https://doi.org/10.1111/ijd.15588
5. Dai D, Ma X, Yan X, Bao X. The biological role of Dead Sea water in skin health: a review. Cosmetics. 2023;10(1):21.
6. Gröber U, Werner T, Vormann J, Kisters K. Myth or Reality—Transdermal Magnesium? Nutrients. 2017;9(8):813.
7. Carbajo JM, Maraver F. Salt water and skin interactions: new lines of evidence. Int J Biometeorol. 2018;62:1345–1360.
8. Proksch E, Nissen H-P, Bremgartner M, Urquhart C. Bathing in a magnesium-rich Dead Sea salt solution improves skin barrier function, enhances skin hydration, and reduces inflammation in atopic dry skin. Int J Dermatol. 2005;44(2):151–157. https://doi.org/10.1111/j.1365-4632.2005.02079.x
9. Chandrasekaran NC, et al. Permeation of topically applied magnesium ions through human skin is facilitated by hair follicles. Magnes Res. 2016;29(2):35–42. https://doi.org/10.1684/mrh.2016.0402
10. Kass LS, Rosanoff A, Tanner A, Sullivan K, McAuley W, Plesset M. Effect of transdermal magnesium cream on serum and urinary magnesium levels in humans: a pilot study. PLoS ONE. 2017;12(4):e0174817. https://doi.org/10.1371/journal.pone.0174817
11. Werner T, Weidner M, Vormann J. Transdermal magnesium – myth or reality? TherapieExpertise (TE). 2017;34(4):45–48.
12. Ham JY, Jang YK, Jeon BY, Shon YH. Magnesium from Deep Seawater as a Potentially Effective Natural Product against Insulin Resistance: A Randomized Trial. Medicina (Kaunas). 2024;60(8):1265.