Bolton's Naturals Magnesium Chloride Gel - Pure magnesium-rich sea minerals which are absorbed directly through the skin and immediately into the cellular tissue. For sports enthusiasts, magnesium is the single most important mineral for maintaining healthy, supple muscles and minimizing calcium build-up that can cramp and tense muscles. Topical application after every work-out replaces magnesium lost through strenuous exercise and stressful lifestyles.