Hormones That Are Misunderstood

Since many people get their information from TikTok, ideas tend to spread quickly, often without much context. Terms like serotonin, dopamine, and cortisol are often repeated and simplified, which makes it

easy for misconceptions about hormones to stick. Here’s what they actually do, and what they don’t:

Image Source: The New York Times, illustration by Yuko Shimizu

Most people think dopamine is just a “happy” chemical, but that can be a very basic understanding of its role in the brain. It's true that dopamine increases during rewarding experiences, but it also plays a huge role in learning, motivation, and reward prediction. Dopamine helps the brain to really want and expect rewards and reinforces behaviors that lead to them, rather than simply producing feelings of pleasure. Eventually, dopamine responds to signals that a reward is coming, which is why habits stick so easily. 

Serotonin was a term that trended for a while, and it almost seemed like people had forgotten about dopamine, as if serotonin were the only “happy” chemical that existed. In reality, serotonin plays a much broader role in the body, helping regulate mood, sleep, appetite, and digestion rather than directly producing happiness. In fact, most serotonin is found in the gut, not the brain. Its main role is helping the body stay balanced, not creating happiness. 

Cortisol is usually described as a “stress hormone”, which in a way gives it a negative reputation, but cortisol can be very important for survival. Cortisol helps regulate the sugar in your body, metabolism, blood pressure, and sleep-wake cycle. Cortisol isn't the hormone that causes "issues," but problems can arise if cortisol levels are chronically elevated, which can occur with long-term stress. In moderation, cortisol plays a necessary and protective role in the body.

Understanding what these hormones actually do helps clarify why reducing them to “happy” or “stress” chemicals misses how complex the brain and body actually are.