You’ve probably heard the narrative. Some kids grow out of ADHD. Others don’t. Some of us masked so well no one realized we had ADHD until later in life. However, even though we’ve finally agreed that adults can have ADHD as well as kids, it’s still true that some of us outgrow our diagnosis (AKA, ‘remission’).
We commonly think this is because we just got better at the basics: eating, sleeping, hydration, exercise, and behavioral skills/tools. Some of us just overcompensate with anxiety or depression, and even the pressure of simply being an adult can be enough to mask adult ADHD.
But new research is pushing back on the common thought that we just got good at masking as we aged—and the real explanation might be sitting in your brain chemistry right now.
And the best part?
We can do something about it—even if you have adult ADHD yourself.
The Neurotransmitter You’ve Never Thought About
In the ADHD world, dopamine gets all the attention. Makes sense. Most of the medications we use work on the dopamine system, so it’s become the shorthand for explaining what’s going on in an ADHD brain. But there’s another neurotransmitter that researchers are increasingly paying attention to: glutamate.
To understand why glutamate matters so much, you have to understand its relationship with GABA. These two neurotransmitters are essentially a teeter-totter system — glutamate excites, GABA calms, and they help balance each other. Together, they account for over 80 percent of brain activity. When they’re in balance, your brain has an easier time focusing or quieting down.
GABA, the main inhibitory neurotransmitter in the human cerebral cortex, is actually synthesized from neuronal glutamate and can be converted back into glutamate in astrocytes. This means the two aren’t just working in opposition — they’re chemically interdependent. The enzyme that does this conversion, glutamic acid decarboxylase (GAD), requires vitamin B6 as a cofactor, which is one reason B6 status matters so much for brain chemistry. Fun fact: We also need B6 in order to make our dopamine!
What The 2026 Study Found
Marine Bouyssi-Kobar et al. followed three groups of people: those with persistent ADHD, those whose ADHD remitted by adolescence, and controls who never had ADHD. Using a specialized brain imaging technique, they measured glutamate levels in the medial prefrontal cortex (the part of the brain that’s central to attention, impulse control, and self-regulation). It’s also a part that tends to develop differently in ADHD brains.
In people whose ADHD persisted into adulthood, glutamate levels in that region increased with age. In both people who remitted and in people who never had ADHD, glutamate levels decreased with age, which appears to be the typical developmental trajectory.
They also found that these glutamate differences were connected to how the default mode network — the brain’s “background noise” system — was communicating with deeper brain regions. If you’ve ever wondered why your brain won’t quiet down when you need to focus, this network is a big part of that story.
Essentially, it means that for people with persistent ADHD, the brain is continuing to develop differently, at a chemical level, well into adulthood.
How to Scientifically Reduce Excess Glutamate
Glutamate and GABA are highly malleable systems, and they are very responsive to environmental changes and task demands. We can make this work in our favor, because it means that nutrition, stress, sleep, and lifestyle factors can all influence where the dial is set on any given day as well as over time. The more we can help bring our glutamate levels back to normal, the less severe our ADHD symptoms should feel.
Nutritionally, you should focus on these nutrients:
Magnesium is probably the most well-supported nutrient in this space. Magnesium acts as a natural blocker of NMDA receptors, which are the primary receptors through which glutamate does its work. When magnesium levels are optimal, it physically sits inside the NMDA receptor channel and prevents excessive calcium influx, protecting against excitotoxicity. To learn more about magnesium and ADHD, read my articles on the topic through this link.
Vitamin B6 is the essential cofactor for the enzyme that converts glutamate into GABA. Without adequate B6, your brain simply can’t make that conversion efficiently, meaning glutamate can build up even when the raw materials for GABA are present. It’s on my list of vitamins and minerals to check to see if your nutritional status is affecting your ADHD symptom severity. You can pick up your ADHD Blood Test Masterlist on my store.
L-theanine, the amino acid found in green tea, works on this system in a few ways. It increases levels of GABA, serotonin, and dopamine, while also acting as a counterbalance to glutamate’s excitatory properties. It’s one of the more accessible tools for supporting the glutamate-GABA axis, particularly for people who are sensitive to stimulants or are looking for gentler support. To learn more about the research on L-Theanine and ADHD, check out my article Does L-Theanine Help ADHD?
Taurine is another amino acid that closely interacts with glutamate. It acts as a modulator of glutamate activity, helps keep glutamate within a healthy range, and regulates calcium flow in neurons — one of the key mechanisms through which excessive glutamate causes damage. It’s found primarily in animal proteins.
NAC (N-acetylcysteine) has been more recently studied for its ability to regulate glutamate, particularly through its effects on the cystine-glutamate transporter. NAC helps the body regulate glutamate levels and can also protect against glutamate’s oxidative effects.
Omega-3 fatty acids also come up consistently in glutamate excess reduction. It’s a powerful anti-inflammatory nutrient. Unfortunately, people with ADHD are at a biological disadvantage with omega-3s, so eating more than the general person is important (fatty fish + seeds).
Finally, lifestyle factors matter just as much or more than our food intake.
- Chronic stress directly impacts glutamate levels and increases neuronal vulnerability. Nervous system regulation skills, as well as, interoception skills are crucial to develop. If you’ve purchased my ADHD Nutrition Manual, you have the first two eBooks that cover exactly how to approach both in a body that seems to be biologically wired for the opposite.
- Sleep: the brain’s glymphatic system, which clears metabolic waste including excess neurotransmitters, is most active during deep sleep.
- Exercise has been shown to support glutamate metabolism and enhance the brain’s natural clearance mechanisms.
What to Take Away From The Study
Whether you’re an adult or a kid with ADHD, focusing on the things that help balance your GABA-Glutamate levels will only benefit you. When glutamate is well-regulated, it’s essential. It drives learning, memory, and neuroplasticity. But when it accumulates in excess, glutamate can shift from neurotransmitter to neurotoxin.
Excess glutamate in the brain is connected with increased cognitive decline and Alzheimers — so focusing on eating plenty of plants and protein, exercising consistently, sleeping well, and reducing your stress is very important if you have ADHD into adulthood. If you have medication, don’t forget to take it! They not only improve your cortisol responses (AKA your nervous system), but they also help you actually do those basic living essentials.
And as always, remember: it’s better to do one thing poorly than nothing at all. Our black-and-white thinking tends to make us avoid doing anything because we can’t do it “exactly” or “perfectly.” Even one tiny action such as eating a piece of fruit along with your donut will help your brain more than doing nothing.
This article summarizes current research for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before making dietary or treatment decisions.
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