What Exactly Is GABA Tea (And Why Are Tea Nerds So Obsessed With It?)
If you've heard of GABA tea, you probably know it as a smooth, calming brew perfect for melting away stress. But before it became a darling of the wellness world, it had a surprisingly rocky start.
Contents
Where GABA tea came from
GABA tea was first developed in Japan in the mid 1980s, by Dr Tsushida and his team of researchers at Japan's National Research Institute of Tea. They were actively looking for ways to create functional food: everyday dietary products enhanced with natural health benefits, to support a rapidly ageing population. During their research, they discovered that placing fresh tea leaves into a completely oxygen-free environment triggered a unique natural reaction, which packed the leaves with stress-relieving amino acids.
However, the tea they produced tasted like a sour medicinal drink, because the original Japanese method used a single long nitrogen flush to force out the oxygen, leaving the tea unpleasantly sour and metallic, so nobody wanted to drink it.
The method was brought from Japan to Taiwan in 1994. In order to improve the taste of the drink, the Taiwanese tea producers started experimenting and developed a cycled nitrogen flush process, moving the leaves between anaerobic and aerobic conditions several times rather than once. This unique processing method transformed the tea's flavour, and paved the way for the delicious, highly sought-after varieties we enjoy today.
But what is GABA?
GABA stands for gamma-aminobutyric acid. It is an amino acid that is naturally produced by your own body and acts as the primary inhibitory neurotransmitter in your central nervous system. In simple terms, GABA is your brain's natural braking system. When things get too stressful, it allows your nervous system to reset by blocking specific signals and decreasing brain activity.
Why is it special in tea?
Apart from being made by your own body, GABA can turn up in trace amounts in foods like kimchi and brown rice. Regular tea, however, contains almost none.
The nitrogen process changes this by forcing the leaf to convert its stored glutamate, an excitatory molecule that tends to wake you up, into GABA, which does the exact opposite. That chemical conversion is why a GABA tea is defined by a number rather than by a flavour. To be officially sold as one, the finished leaf must carry at least 150 milligrams of GABA per 100 grams.
Does it actually calm you down?
So does that mean that on a genuinely stressful day, a cup of this will fix it?
Honestly, there is no simple answer to that.
Studies have found that GABA taken orally struggles to enter the brain, because of the blood-brain barrier, which acts as a protective shield keeping toxins and various molecules out of the brain. On that evidence alone you would expect drinking it to do very little.
And yet trials have still observed measurable effects in people drinking GABA tea: lower heart rate, improved heart rate variability, reduced cortisol, and an increase in alpha brain waves, which are associated with wakeful relaxation. Something is happening even though the obvious route is closed.
The explanation seems to be a combination of things rather than one. Ingested GABA can interact with receptors in your digestive tract, often called your second brain, which signals upward through the vagus nerve. That sits alongside the plain placebo effect of a slow, comforting ritual, which is real and worth counting rather than dismissing. And GABA works as a teammate to other compounds in the leaf, particularly L-theanine, which does cross into the brain easily and triggers your own relaxation pathways. Together they seem to do something that no single isolated compound manages on its own.
What I can tell you with confidence is that the molecule is real and the quantity in the leaf is measurable. What happens after that is still being worked out, and anybody selling you certainty about it is selling you something other than tea.
What it tastes like
The health side is only one half of this, and for most people, it is not even the interesting half. The nitrogen process drastically alters the natural chemistry of the leaf, stripping away traditional astringency and replacing it with a comforting, rounded mouthfeel.
Good GABA tea is unusually smooth, naturally sweet, and remarkably low in bitterness. It carries a creamy, fruit-forward complexity that you do not get anywhere else, often accompanied by a signature, pleasant sweet-and-sour tanginess.
The flavours vary beautifully with the base tea, from deep notes of honey, caramel, and stewed stone fruits in Oolong to something clean, savoury, and umami in green tea.
Whatever the variety, the defining characteristic is the texture, which is thick and creamy. Because the processing limits the formation of bitter catechins, what is left is a brew that glides down the throat without drying out your mouth.
A GABA from Darjeeling
Almost all GABA tea comes from Taiwan, where the technique took hold after it left Japan and where it has been refined for decades. Darjeeling is not somewhere you would expect to find it, and until recently you would not have.
Ours came out of an experiment by Sonam, who explains that so much depends on the season and the weather, on what the leaves will allow you to make in any given year. In this particular summer the sun was generous and the conditions were unusually good, and it became possible to attempt something like this at all.
He made it from seed-grown Assamica bushes rather than the small-leaf clonal plants and traditional Camellia sinensis var. sinensis behind most tea from these hills, and the choice was not incidental. Assamica excels at GABA tea because it has a better chemical and physical build for it than the more delicate sinensis leaf. Chemically it carries much higher levels of glutamic acid, which is the fuel for the conversion, alongside malty, chocolatey notes that effortlessly mask the sour metallic tang the nitrogen process can leave behind. Physically its larger, tougher leaf withstands ten hours of vacuum sealing and tumbling without tearing.
Because the leaf is longer and thicker, it holds an incredible depth of flavour: date molasses, candied apple, baked sweet potato, with a creamy body and a long sweet finish. It takes gongfu brewing and western brewing equally well, and it will go bolder if you push it.
It was a single experimental micro-batch from one unusually good summer, which means that when it is gone there may well not be another like it. That is true of a great deal of tea from small growers and it is rarely said out loud, so it is worth saying here.
The tea in this article
GABA Oolong, a rare GABA oolong from Darjeeling
Sources
- Tsushida, T. and Murai, T. (1987). Conversion of glutamic acid to gamma-aminobutyric acid in tea leaves under anaerobic conditions. Bioscience, Biotechnology, and Biochemistry.
- Wang, H. et al. (2001). Cycling treatment of anaerobic and aerobic incubation increases the content of gamma-aminobutyric acid in tea shoots.
- Investigation on the quality of commercially available GABA tea in Taiwan, on the 1994 transfer from Japan.
- Hepsomali et al. (2020). Effects of oral gamma-aminobutyric acid administration on stress and sleep in humans: a systematic review. Frontiers in Neuroscience.
- Sonam, on making this batch and the summer that allowed it.