Peppermint oil has been shown to relax muscles in the digestive system and improve various digestive symptoms. Research suggests that peppermint oil reduces tension headaches and migraines. Peppermint oil has been shown to relieve fatigue and daytime sleepiness although peppermint tea is an ideal choice before bed, as it’s naturally caffeine-free. Peppermint’s capacity as a muscle relaxant may help you relax before bedtime. It is also known to improve concentration and aid in weight loss.