Is the magnesium bath from Bath & Body Works worth it?

What we could and couldn't verify about the Bath & Body Works product

Bottom line: we can't confirm what this product contains. We found no Bath & Body Works product page, label, or test data for a magnesium bath, and we couldn't reach the brand's site. That leaves the salt type, its concentration, and its claims unknown.

Check the packaging or ask the company directly before you assume anything about the formula. Any claim that a bath eases muscles or treats a condition needs support you can see, and we found none for this product.

The regulatory picture is also murky. A magnesium-based balm on DailyMed carries the FDA disclaimer that it has not been found safe and effective, and its magnesium concentration isn't specified (DailyMed magnesium balm label).

Does magnesium actually get through your skin?

Bottom line: the evidence says not in meaningful amounts. Examine reports a lack of evidence that magnesium sulfate (Epsom salt) baths deliver magnesium through the skin, and says any relaxation from a warm soak probably isn't due to the magnesium (Examine magnesium summary).

A narrative literature review of transdermal magnesium, covering sprays, flakes, and salt baths, concluded the claim is scientifically unsupported (PubMed review on transdermal magnesium). It's a narrative review, not a systematic review or meta-analysis, so it summarizes the literature rather than pooling data.

Cleveland Clinic makes a similar point: no definitive studies show skin absorption of magnesium in amounts that would correct a deficiency (Cleveland Clinic on Epsom salt).

The one human trial tested a cream, and it's small

Bottom line: the strongest human data we found tests a cream, not a bath, and it doesn't prove much. A pilot randomized trial gave 25 adults a 56 mg/day magnesium cream or placebo for two weeks.

Serum magnesium rose from 0.82 to 0.89 mmol/L in the cream group, but that change wasn't statistically significant overall (p = 0.29). It reached significance (p = 0.02) only in a subgroup of non-athletes, and the placebo group barely moved. The authors called the dose low and suggested higher doses over longer periods in future work (pilot study of transdermal magnesium cream).

A cream, a small sample, and a two-week window tell you little about a soak in the tub.

What about the chemo study?

Bottom line: a recent study reported that Epsom salt foot baths helped with chemotherapy-related nerve symptoms, but we couldn't verify its design. The snippet we could access gives no sample size, bath dose, or effect size, so treat it as a lead rather than a finding (study of Epsom salt foot baths in chemotherapy patients).

If you still want the soak, use it safely

Bottom line: a warm bath is low-risk for most people if you follow the label. The Epsom salt label directs two cups added under warm running bath water (DailyMed Epsom salt label).

The same label says people with diabetes should not use warm or hot soaks without a physician's advice, and that soaks should stop if redness, irritation, swelling, or infection occurs. Mayo Clinic lists skin infection after soaking among possible side effects (Mayo Clinic magnesium sulfate entry).