Mace, the dried lacy covering of the nutmeg seed (Myristica fragrans), has a long history of traditional use in various systems of medicine, including Ayurveda and Unani, for supporting sleep and treating insomnia. In these traditions, mace is often used for its purported calming and sedative properties, and it is sometimes included in herbal preparations aimed at promoting relaxation or restful sleep. The use of mace for insomnia is primarily justified by this historical precedent rather than robust scientific evidence.

From a scientific perspective, there are very limited studies that directly evaluate the efficacy of mace in treating insomnia. Some animal studies on nutmeg (which contains similar volatile oils and compounds as mace) have demonstrated mild central nervous system depressant effects, but these findings are not directly translatable to mace or to human insomnia treatment. Clinical trials in humans assessing mace for insomnia are lacking. Therefore, while traditional use exists, the scientific evidence supporting mace's effectiveness for insomnia is weak and largely anecdotal.

In summary, mace is used in traditional medicine for insomnia, but there is insufficient scientific validation to recommend its use for this purpose.