BetterYou Magnesium Muscle Bath Flakes – Recover and Relax. Soothe tired muscles with BetterYou Magnesium Muscle Bath Flakes. Made with pure Zechstein magnesium chloride and invigorating lemon and rosemary, these flakes help relax muscles and support recovery. Add 250g to your bath or 150g to a footbath, and soak for 20 minutes. Recharge naturally with BetterYou Magnesium Muscle Bath Flakes.