1. Eyelid Twitching: Low levels of magnesium can cause muscle spasms and twitching, including eyelid twitching. 

2. Difficulty Sleeping: Magnesium is involved in the promotion of sleep by increasing gamma-aminobutyric acid levels in the brain. Lack of magnesium can result in difficulty falling asleep. 

3. Irregular Heartbeat: Magnesium plays a crucial role in heart function. Insufficient magnesium levels can lead to abnormal heart rhythms. 

4. Fatigue: Magnesium is essential for cellular energy production. Lack of magnesium can result in fatigue and overall weakness. 

5. Migraines: Magnesium deficiency can trigger frequent headaches and migraines due to abnormal brain contractions and dilations.

Magnesium is vital for various bodily functions.