Exposure to bright light has been shown to increase serotonin levels, yet modern life keeps most people indoors for long periods of time. Even on a cloudy day, it’s important to spend time outside to help reset serotonin levels.
You can also purchase full-spectrum lights or light therapy lamps to use indoors at your desk, in your living room, or other places where you normally spend time. They should be at least 10,000 lux to help boost serotonin levels.