[1] The twitching can occur in any voluntary muscle group but is most common in the eyelids, arms, hands, fingers, legs, and feet.

[2] Other common symptoms are generalized fatigue or weakness, paraesthesia or numbness, and muscle cramping or spasms.

[6] Benign fasciculation syndrome is a diagnosis of exclusion; that is, other potential causes for the twitching must be ruled out before BFS can be diagnosed.

[4][2] Lack of clinical weakness along with normal EMG results (in those with only fasciculations) largely eliminates more serious disorders from potential diagnosis.

[2][3] In younger people with only lower motor neuron (LMN) fasciculations, no muscle weakness, and no thyroid abnormalities, Turner and Talbot (2013) state that "individuals under 40 years can be reassured without resorting to electromyography (EMG) to avoid the small but highly damaging possibility of false-positives".

[3] According to Kincaid (1997), the diagnosis is made when there is no clinical finding of neurogenic disease; he first reassures patients that no "ominous disease seems to be present", and says, "I suggest that patients like this be followed for a year or longer with clinical and electromyographic exams at about 6-month intervals before one becomes secure in the diagnosis that the fasciculations are truly benign.

The site of the fasciculations, for example, those in the calves versus abdomen, has not been shown to be discriminatory for a benign disorder.

[9][10] A 2017 study by Neurology.org also found that Benign Fasciculations are common in the general population, occurring in about 70% of healthy individuals and almost never associated with a serious neuromuscular disorder.