What percentage of Magnesium is the Swanwick Sleep Magneisum Oil Spray? Sarah A December 27, 2017 01:10 Updated Follow 50% magnesium. Related articles What is Magnesium Oil Spray? What's different about your Sleeping Mask? How are your glasses different from other cheaper glasses? What's the difference between the clear lens and orange lens Swannies? How do I use the Magnesium Spray? Comments 0 comments Article is closed for comments.