What Is 5-HT? Understanding Serotonin and Its Effects

5-HT, or serotonin, is a neurotransmitter that helps regulate mood, anxiety, and cognition. Along with dopamine and norepinephrine, it’s part of a group of brain chemicals known as monoamines – key players in emotional balance and mental health.

Since the 1950s, antidepressants like SSRIs have been designed to regulate serotonin, norepinephrine, and dopamine activity. While SSRIs prevent serotonin from being reabsorbed too quickly, 5-HT supplements work differently – attempting to boost serotonin levels, by bypassing a rate limiting step in their creation (the conversion of tryptophan to 5-HTP, which requires an enzyme that can be negatively affected by stress, illness and nutritional deficiencies).

Increasing the availability of serotonin to one’s neurons (their brain cells) may seem like a universally good thing, but in-fact, just like SSRI’s  (selective serotonin re-uptake inhibitors, like Prozac, Zoloft and Lexapro) or other psychiatric medications that interact with serotonin receptors in the central nervous system, there are potential side effects, – and some serious – with 5HT, St. John’s Wart and other “serotonergic supplements.”

Unlike SSRIs, which are regulated and standardized, 5-HT and other serotonergic supplements are not tightly monitored. Independent testing has found that supplement labels don’t always match what’s inside. That’s why  I always recommend using a well-known and established large company that holds itself to rigorous third-party certifications, such as Nature Made or Nature’s Way.

5-HT and St. John’s Wort can act as very mild antidepressants, similar in concept to SSRIs, but far less controlled. Like prescription antidepressants, they can cause significant (even dangerous) side effects. Side effects of 5-HT, St. John’s Wart and other serotonergic supplements can include stomach upset, headaches, dizziness, nausea, low energy, decreased libido, other sexual side effects, vivid dreams, agitation, anxiety and even suicidal ideation (among others). If a patient has undiagnosed bipolar disorder, a 5-HT supplement could actually cause them to enter a “mixed state,” with low mood, racing thoughts, decreased ability to sleep and agitation. Any product that alters serotonin should be approached with the same caution as a prescription medication.

Many people don’t realize how dangerous it can be to combine serotonergic supplements like 5-HT or 5-HTP with antidepressants such as SSRIs. Mixing them can trigger serotonin syndrome, a life-threatening reaction that causes confusion, unstable vital signs, seizures and worse. Even small amounts of 5-HT, St. John’s Wort, or recreational drugs like MDMA can raise serotonin to toxic levels (particularly when taken in combination with other supplements or medications). I always advise patients to avoid taking 5-HT supplements and SSRIs together unless closely monitored by a medical professional.

If you’re pregnant or planning to become pregnant, it’s important to talk with your OB-GYN before taking any serotonergic supplement. 5-HT, St. John’s Wort, and similar products can affect fetal development and may pass into breast milk. While some people see them as natural, “natural” doesn’t always mean risk-free. A conversation with your doctor ensures safety for both you and your baby.

For those with mild anxiety or low mood, trying a supplement like 5-HT can seem like a low-risk first step. I understand that instinct – but even mild symptoms deserve professional evaluation before starting anything that affects brain chemistry. A psychiatrist or nurse practitioner can help determine whether a supplement, SSRI, or another approach makes the most sense. That way, you can make an informed and safe choice.

If you’re exploring serotonin-boosting supplements or comparing 5-HTP vs SSRIs, it’s best to start with a professional consultation. Our team can evaluate your symptoms, review potential interactions, and recommend a plan that fits your needs. Every person’s neurochemistry is different, and personalized care makes all the difference. We’re here to guide you toward safe and effective treatment options.