A combination of melatonin, zinc, and magnesium has been shown to be safe and effective in treating insomnia in older men and women, but the results are preliminary.
Insomnia is an extremely frustrating problem for many older patients and their clinicians. In this randomized double-blind trial from Italy, researchers enrolled 43 residents (mean age, 78) of a long-term care facility; all met criteria for primary insomnia, and none had psychiatric diagnoses or dementia.
Participants received either placebo or a nightly supplement that consisted three natural medications:

• melatonin – 5 mg
• zinc – 11.25 mg, and
• magnesium – 225 mg.

The authors’ stated rationale for including zinc and magnesium was that previous research suggested these substances improve mood and enhance endogenous synthesis of melatonin — even though previous clinical trials of melatonin alone for insomnia have yielded mixed results.
After 60 days of treatment, the supplement group exhibited highly significant improvement on a validated sleep quality index (mean change, 7 points on a 21-point scale), compared with no change in the control group.
Significant changes on secondary measures (other sleep scales, a quality-of-life survey, and a depression scale) also favored the supplement group. No adverse effects were recorded.
These results are almost seem too good to be true—an apparently safe and highly effective treatment for primary insomnia.
Additional research to replicate these findings in other populations and to assess longer-term safety and efficacy is essential.
But, in the meantime, the intervention might be worth a try in selected patients for whom standard sleep hygiene measures have been unsuccessful.