When soil is contaminated with heavy metals, plants struggle to grow. A new review of 140 studies looked at how melatonin, a natural hormone, might help.
The review combined data from 2,476 observations across different plant families. It found that adding melatonin significantly improved overall plant performance. Plants showed better growth, stronger roots and shoots, and more chlorophyll. They also had higher antioxidant activity, which helps fight cellular damage from the metals.
The analysis showed melatonin increased plants' own melatonin levels and helped them take up fewer heavy metals. However, the review notes that very high metal levels or long exposure can make melatonin less effective.
This is a review of studies on plants, not a clinical trial for people. It shows melatonin's potential to help crops and other plants in contaminated soils, but more research is needed to confirm how it works in real-world farming.