The science behind the green powder drink
By Science Served
If you’ve walked into a coffee shop in the past few years, you’ve seen it - the swirl of deep green in a matcha latte, usually served with oat milk and a side of health claims. It's everywhere. From viral smoothies to aesthetic cafes to collagen rich matcha protein bars, the powdered tea has exploded into trend culture with a reputation for health & wellness.
But what is matcha really doing to your body and does it actually live up to the hype?
As a nutrition science student, I’ve been digging into the biochemistry and health effects of matcha to understand what this ancient drink offers in the modern wellness world. And what I’ve found is that while matcha has serious benefits, not all matcha is created equal, and if you're drinking it blindly for "antioxidants" without knowing the science, you're probably missing the point.
Okay so let’s break it down and really talk about this.
What Exactly is Matcha?
Matcha is made from Camellia sinensis, the same plant used to make all ‘true’ teas, that is, green, black, oolong. But what sets matcha apart is how it's grown and processed.
For about 20 days before harvest, the tea plants are covered with bamboo mats or tarps to block out sunlight (shade-grown). This increases chlorophyll levels, giving matcha its vivid green hue. It also gives matcha leaves the ability to retain significantly higher amounts of L-theanine, an amino acid that functions as a precursor to calming neurotransmitters like GABA and dopamine. This is part of what gives matcha its signature “Zen” effect, balancing out its caffeine content without the jittery crash that coffee often causes.
After harvest, he leaves are steamed, de-stemmed, and then finely ground into a powder (stone-ground), which means when you drink matcha, you’re consuming the entire leaf and not just steeped water like in regular green tea.
So because of that, matcha contains more of everything (more antioxidants, more caffeine, more nutrients). But also, more potential for harm if consumed excessively.
L-Theanine + Caffeine
Matcha’s most famous claim is that it delivers “calm focus.” And the science actually backs that up. The caffeine content of matcha is about 19-44 mg per gram, depending on how it's processed. For reference, this is higher than green tea but less than coffee. But what makes matcha different, giving it its USP, is L-theanine, an amino acid that passes the blood-brain barrier and promotes alpha-wave brain activity. FYI, that is the same brain state associated with meditation.
Multiple human studies have shown that the combination of caffeine + L-theanine
- Improves attention and reaction time
- Enhances working memory
- Reduces the jitters or energy crashes typically seen with coffee
So yes, your matcha latte can help you study or focus more clearly. But not all matcha has the same L-theanine content, especially lower-quality powders made from older, sun-exposed leaves.
Iron
Matcha is rich in polyphenols, which are basically powerful plant compounds, but at the same time, they come with both pros and cons. While they act as antioxidants in the body, polyphenols can also inhibit the absorption of non-haem iron (the type of iron found in plant-based foods).
But here’s what you should actually understand
- It doesn’t deplete your iron stores. Matcha only interferes with “new” iron absorption, meaning, the iron you’re currently consuming. It won’t wipe out the iron already circulating in your bloodstream.
- Red meat is less affected. Haem iron from animal sources (like beef or chicken liver) is absorbed more efficiently and isn’t blocked as much.
- It’s all about timing. To minimize any impact, drink your matcha 1-2 hours away from iron rich meals or iron (Fe) supplements.
- Pair iron with vitamin C. This boosts absorption. Think citrus fruits, berries, bell peppers, or even a squeeze of lemon on your salad. If you're taking an iron supplement, a glass of orange juice truly goes a long way.
If you’re at higher risk of being iron-deficient, you might want to talk to a healthcare professional before making matcha a daily ritual. This may unintentionally be blocking the very nutrients you’re trying to improve.
Antioxidants
Another one of matcha’s health claims is its antioxidant capacity, particularly its catechins. The main one, epigallocatechin gallate (EGCG), is a polyphenol with anti-inflammatory and anti-carcinogenic properties.
- In vitro studies show EGCG can inhibit cancer cell growth
- Animal studies suggest matcha reduces oxidative stress and free radical damage
- Human studies link green tea catechins to improved heart health and weight management
But here’s what most people don’t know; matcha may also contain more caffeine and EGCG than your liver is ready to handle, especially if you’re drinking it in concentrated shots or even capsules.
A 2020 meta-analysis of 15 randomized controlled trials found that while green tea catechins decrease liver enzymes in patients with non-alcoholic fatty liver disease, they actually increased liver enzymes in healthy individuals, suggesting that too much could have adverse effects.
- Increased liver enzymes are often associated with liver stress or damage.
- Decreased levels generally reflect improved liver function and reduced hepatic strain.
Stick to less than 4 grams per day unless advised otherwise, and always, always, always choose third-party tested, organic matcha to avoid pesticide residues and heavy metals like lead.
Not All Matcha Is Created Equal
Most of what’s marketed as matcha in chain stores and online recipes isn’t ceremonial-grade - the highest quality variety that’s shade-grown, vibrant green in color, smooth in taste, and often quite expensive. Many matcha lattes sold in cafes are made from culinary-grade matcha, which is less shade-grown, more bitter, and less nutrient-dense. Worse, some are made from green tea powder mixed with food dyes and fillers - not true matcha at all. These versions typically lack both L-theanine and chlorophyll, stripping away the very compounds responsible for matcha’s signature “calming energy” and nutritional benefits.
If the price seems too good to be true…it probably is. Real matcha is expensive to produce. If you’re buying it for health, invest in quality or you might just be drinking artificially colored tea powder that offers little to no benefits.
Heart health & Metabolism
Matcha may support heart health by
- Lowering LDL (bad cholesterol)
- Reducing blood pressure in some individuals
When it comes to weight management, catechins (especially EGCG) combined with caffeine have been shown to slightly boost thermogenesis and fat oxidation. But don’t expect matcha to melt belly fat because it’s not a miracle solution. It only works best when paired with diet and movement.
Biochemistry
- Chlorophyll which supports detox enzymes and is an antioxidant
- Theogallin & gallic acid which have additional antioxidant activity
- Succinic acid which may contribute to energy metabolism
However, these compounds are preserved only under very specific conditions. They need to be steamed instead of pan-fried (unlike Chinese green tea) and dried at controlled temps. Additionally. It needs to be stored in opaque, airtight containers.
And yes, preparation also matters. Don’t use boiling water as it destroys L-theanine and catechins. Aim for 160-175°F (70-80°C) and whisk with a bamboo chasen for best results.
Side Effects?
Now let’s Talk Risk…
Matcha is safe but in moderation. Otherwise, you may experience
- Anxiety, heart palpitations, or disrupted sleep
- Reduced iron absorption from high catechin levels
- Elevated liver enzymes if consumed excessively (esp. in supplement form)
Also, because you're consuming the whole leaf, you're also ingesting everything the plant absorbed, which includes pesticides, herbicides, or even heavy metals if not grown organically.
Pro tip? Always choose organic, Japanese-sourced, lab-tested matcha.
It's incredibly versatile. You can add it to smoothies, chia puddings, baked items (just be aware high heat can degrade antioxidants), yogurt bowls, etc.
My final thoughts
Matcha is trendy and that’s okay. But you need to keep in mind that it is also a functional food with real biochemical effects on your body. Like anything in nutrition, the dose and quality matter more than the marketing on the product label.
Drink it for its nutritional profile and/or even its cultural history. But just don’t fall for empty health claims or knock-off versions. Make sure you know what you’re consuming.
And please skip the neon-green powder from Amazon.
ScienceServed - no hype, just human biology