What causes muscle twitching (fasciculations)?

From the Guidelines

Muscle twitches are typically caused by involuntary contractions of muscle fibers, often resulting from minor nerve irritation, and can be triggered by various factors including fatigue, stress, exercise, caffeine consumption, dehydration, certain medications, and electrolyte imbalances. The provided evidence [1

From the Research

Causes of Muscle Twitching

• Electrolyte imbalances, such as disturbances in sodium, potassium, calcium, magnesium, and phosphorus levels, can cause muscle twitching 1, 2, 3
• Fluid imbalances and acid-base disturbances can also lead to muscle weakness and twitching 4, 1
• Specific electrolyte imbalances, such as:
  • Hypomagnesemia (low magnesium levels) can cause muscle spasms, weakness, and tetany 1, 3
  • Hypocalcemia (low calcium levels) can lead to muscle spasms, weakness, and tetany 1, 3
  • Hypophosphatemia (low phosphate levels) can cause weakness and impair respiratory function 1, 3
• Other factors, such as:
  • Hyponatremia (low sodium levels) can cause seizures and muscle weakness 2, 3
  • Hyperkalemia (high potassium levels) can cause muscle weakness and cardiac arrhythmias 1, 5