Herbal traditions have long suggested that certain plants can promote restful sleep. This belief has found new life on social media, where drinking “lettuce water” or “lettuce tea” has become a popular natural remedy for sleeplessness. The idea is simple: steeping lettuce leaves in hot water creates a mild brew that proponents claim helps people fall asleep faster and stay asleep longer. This contemporary trend echoes a historical use of lettuce as a gentle hypnotic, prompting an examination of the scientific foundation supporting this folk remedy.
Identifying the Sleep Compound in Lettuce
The claims about lettuce as a sleep aid center on lactucarium, a milky sap that exudes from the base and stems of the plant when cut or bruised. This sap contains a mixture of chemical compounds attributed with soothing properties.
The primary active components in this fluid are two sesquiterpene lactones: lactucin and lactucopicrin. These bitter substances are structurally related to compounds found in other plants and are believed to act on the central nervous system. Historically, the concentrated dried sap from wild lettuce (Lactuca virosa) was called “lettuce opium” because it was used as a mild sedative and pain reliever in the 19th century, sometimes substituting for opium.
Lactucin and lactucopicrin possess mild analgesic and sedative properties. While the wild variety, Lactuca virosa, produces the highest concentration of lactucarium, common cultivated lettuce (Lactuca sativa), such as Romaine, also contains these compounds in much smaller amounts. The presence of these specific compounds provides a plausible chemical basis for the traditional belief that lettuce can influence sleep.
Scientific Evidence Supporting Sleep Effects
Research has explored the potential of lettuce extracts, focusing primarily on concentrated lactucin and lactucopicrin. Several animal studies indicate these extracts affect sleep architecture. For instance, administering concentrated lettuce extract to mice decreased sleep latency (the time it takes to fall asleep) and significantly increased total sleep duration.
The mechanism involves action on the central nervous system, suggesting the sleep-enhancing activity is related to the GABAergic system. The GABAergic system is a major inhibitory pathway in the brain, and many pharmaceutical sleep aids target this system to promote relaxation and sleep. Furthermore, certain extracts, particularly those from red romaine lettuce, have been found to increase the duration of non-rapid eye movement (NREM) sleep in animal models.
Translating these findings to human consumption of lettuce water is challenging because animal studies used highly concentrated extracts, often derived from specific, high-potency varieties, or used seeds rather than leaves. However, one human clinical trial involving a highly-concentrated extract derived from a specific cultivar of Korean lettuce showed promising results. Participants reported a better overall sleep quality index score, along with objectively measured improvements like longer sleep duration and less time awake after falling asleep.
The major limitation remains the significant difference in potency between a pharmaceutical-grade extract and a simple home-brewed cup of lettuce water. The amount of lactucin and lactucopicrin transferred into the water from steeping standard grocery store lettuce is likely minimal. Therefore, while scientific evidence supports the sedative potential of the active compounds in high doses, there is limited clinical evidence to confirm that a DIY lettuce tea will provide a measurable hypnotic effect for the average person.
Preparing Lettuce for Sleep Consumption
The preparation of lettuce tea or water is a straightforward process aimed at extracting the mild sedative compounds into the hot liquid. Romaine lettuce is the variety most frequently suggested, as it is known to have a higher concentration of the active compounds than varieties like iceberg.
To prepare the brew, take a handful of outer leaves or a portion of the inner stem and steep them in a cup of boiling water for five to ten minutes, similar to making traditional herbal tea. Some people prefer to boil the leaves for a short time, then strain the solids before drinking the remaining liquid.
The resulting beverage is usually consumed warm. Individuals often add a small amount of honey or a non-caffeinated tea bag, such as peppermint, to improve the flavor. The customary recommendation is to drink the lettuce water about 30 minutes before bedtime, allowing the warm beverage to become part of a relaxing nightly routine.