Glutamate is an amino acid that occurs naturally in the body. It is also a flavor enhancer used in many foods. However, the effects of these two forms of glutamate on the body are completely different. In other words: while it is the exact same chemical substance—L-glutamate—its location and how it is regulated within the body differ entirely.

As a messenger substance in the brain—also known as a neurotransmitter—glutamate transmits specific excitatory signals and is, for example, central to learning and memory. Because the effects of this messenger substance can vary, experts refer to the glutamate system and the balance within this system. If the glutamate system falls out of balance—for instance, in its relationship to the calming and inhibitory GABA system—mood and drive can suffer. However, this does not mean that glutamate alone can trigger a depression. Instead, it is one of many puzzle pieces that can contribute to the development of depression, alongside factors such as life experiences, stress, genetics, and current life circumstances.

In the rest of the body, L-glutamate primarily functions as an amino acid. Most glutamate is produced within the body's own cells. In fact, the body manufactures a massive amount of it, because glutamate is the linchpin of our metabolism and a fundamental building block of proteins. Dietary intake plays only a minor role in this process.

In food, glutamate occurs naturally in items such as tomatoes, mushrooms, cheese, and soy sauce. On the other hand, the glutamate variant monosodium glutamate (MSG) is added to many processed foods as a flavor enhancer. This dietary glutamate is largely broken down and utilized in the gut before it can ever reach the brain. Only a very tiny amount passes through the blood-brain barrier, as the brain predominantly supplies itself. In short: MSG does not influence the brain.

According to the European Food Safety Authority (EFSA), the estimated daily intake from food remains below the safety threshold for most people. However, higher consumption can cause temporary discomfort in sensitive individuals—some people report experiencing headaches, flushing, or palpitations after eating highly seasoned dishes. Glutamate is not considered a trigger for diseases.

Think of the brain as city traffic: glutamate represents the green lights, and GABA represents the red lights. Without the green lights, nothing moves forward; without the red lights, there would be chaos. In a depression, some of these traffic lights seem to be poorly timed.

In other words, during a depressive episode, the balance between glutamate and GABA appears to be shifted. Certain switching points (receptors) on the nerve cells then react differently than usual, which can negatively impact both mood and drive.

Research does not present a uniform picture: depending on the brain region, phase of the illness, and the specific group of individuals, imaging and cerebrospinal fluid samples sometimes reveal increased and sometimes lower glutamate signals. While these measurements aid scientific understanding, they are not suitable for a medical diagnosis—there is no simple blood test available, such as the ones used to check vitamin levels.

The most well-known treatment is Esketamine nasal spray. It targets specific docking sites (receptors) and can rapidly alleviate symptoms in cases of treatment-resistant depression. However, this treatment is administered strictly under specialist medical supervision with mandatory observation in a practice or clinic, and it is used only as an add-on to an ongoing, standard treatment. Other active ingredients that influence different glutamate switches are currently being researched but have not yet been approved for routine medical use.

Depression is an illness. It has many causes and many faces, and it is nobody's fault. The path out of depression is often a combination of talk therapy, medication, daily support systems, and patient self-care.

The most important thing to remember is that you do not have to do this alone. Doctors and therapists are there to guide and support you. Even small steps count, and with each step you take, the next one becomes a little easier.

Cognitive Behavioral Therapy, or CBT for short, is a well-researched form of psychotherapy. It helps you notice distressing thoughts and examine them with some distance. Together with your therapist, you practice new perspectives and small actions that are good for you. This could be a daily schedule, a short walk, a phone call to a trusted person, or a simple breathing exercise. CBT is practical and meets you right where you are in your daily life. After a few weeks, many people begin to feel that life is becoming brighter again.

Medications for depression in the form of antidepressants can help when symptoms are severe or long-lasting. They do not work immediately; it usually takes a few weeks to see an effect. These medications adjust messenger substances in the brain to stabilize mood, sleep, and drive. Doctors will select the right medication together with you and guide you through the start of your treatment. While side effects can occur, many of them subside after a short time. It is crucial that you do not change anything on your own; if something feels uncomfortable, discuss it openly with your doctor. Sometimes the dose can be adjusted, or a different medication can be chosen. Antidepressants act as a support system—they do not change your personality, but rather give you the solid ground needed to make therapy and daily life more manageable again.