Sunflower lecithin doesn’t have a specific time frame of action. Unlike medically prescribed drugs that come with dosage and time interval of consumption, sunflower lecithin is, however, a food supplement. According to individuals who have used sunflower lecithin, it takes about two days to start seeing the benefits, especially for breastfeeding mothers. The best lecithin supplement for weight loss will take weeks for an individual to begin seeing notable changes. In all, the time it takes for lecithin work depends on what a person aims to achieve with it.