Table 5.

Comparison of pre- and post-trial melatonin levels (pg/mL) between treatment groups.

Variable	T1	T2	T3	T4	Chi-square	p-value
Pre-trial melatonin (mean rank)	170.70	135.57	142.12	136.13	8.22	0.140
Post-trial melatonin (mean rank)	157.10	111.97	144.17	171.11	20.7	0.000*

*p-value was obtained by the Kruskal–Wallis H test with <0.05 level of significance. Data presented in mean rank.

T1: Placebo (starch tablets 250 mg × 2).

T2: Magnesium (250 mg × 2).

T3: Potassium (250 mg × 2).

T4: Magnesium + potassium (250 mg × 2).