Is taking Melatonin every night safe long term?

Long-term safety is unclear: one study linked regular use to a 90% higher chance of heart failure, but did not prove it caused harm. Prevention reports on a study presented by the American Heart Association in 2025. It looked at adults with Insomnia / Difficulty Falling Asleep. Those with recorded Melatonin use for at least a year were compared with non-users. The study found more hospital stays for heart failure among users. Their chance of dying from any cause was also nearly twice as high. These links do not show cause and effect. The source does not give the actual number of heart failure cases. So, the 90% figure cannot tell us how common it was. There is another important gap: use was counted through official health records. People buying the supplement without a prescription would not have been counted as users. That makes the comparison harder to interpret. These findings also do not settle the question of occasional use. The article raises a separate concern about product labels. It cites a paper warning that supplement content may be up to 478% higher than labeled. That means the dose on the bottle may not match what someone takes. For BioSocial members, this is a reason to compare more than bedtime habits. Logs can include the brand, labeled dose, timing, and nights used each week. Pairing those details with Sleep Duration can make community comparisons more useful. Better sleep numbers alone cannot establish long-term safety. What changes have you noticed in your sleep numbers across different doses or patterns of use?