What does research say about chai tea and its spices?

Does chai tea have L-theanine? Yes, from its black tea. What research measures for its L-theanine, caffeine, cardamom and ginger, and where it stops.

By PGP Iyer · April 20, 2026 · Updated September 27, 2026 · 5 min read

Chai is a spiced black tea: black tea brewed in milk and water with spices that most often include cardamom, ginger and cinnamon. Yes, chai made on a real tea base contains L-theanine, because that amino acid comes from the tea leaf, not the spices. For the spices themselves, see the spices in chai.

Does chai tea contain L-theanine?

Yes, when the chai is built on true tea (Camellia sinensis). L-theanine is a free amino acid in the tea leaf; the spices add none. A caffeine-free "chai" made on rooibos or herbs has no tea leaf, so it has no L-theanine either.

How much ends up in a cup is a measurement question, and two numbers answer different things:

• In the leaf. Dried tea leaves are described as containing about 1 to 2% theanine as a free amino acid (Boros et al., 2016, citing earlier work).
• In a brew, as measured. The same team steeped 1 g of each commercial tea in 100 ml of 80°C water for 3 minutes. Black teas released an average of 5.13 mg of L-theanine per gram of tea, against 6.56 mg for green teas, and results varied widely from one tea to the next.

That 3-minute steep did not pull out everything: in the authors' own extraction test on a green tea, a much longer steep yielded about twice the theanine. So the amount in your cup depends on the tea, how much of it you use and how long it steeps, and we do not put a single per-cup figure on it. Milled teas such as Spice Rush are stirred in and drunk whole rather than steeped and strained, so steep-based measurements do not describe them directly.

Researchers have studied L-theanine and caffeine together. In one 2008 study (Owen and colleagues, Nutritional Neuroscience), 27 volunteers took 50 mg of caffeine with or without 100 mg of L-theanine, and the researchers reported faster, more accurate attention-switching task scores for the combination than for placebo. Those were measured doses given in a lab, and the study says nothing about a cup of chai, so we describe it as research only. For more on the pairing, see L-theanine and caffeine in tea.

How much caffeine is in chai compared with coffee?

Usually less than a cup of coffee, but it depends on the cup. The FDA lists black tea at 71 mg of caffeine per 12 fl oz (about 47 mg per 8 oz) and regular brewed coffee at 113 to 247 mg per 12 fl oz (about 75 to 165 mg per 8 oz). Spice Rush is about 40 to 50 mg per scoop. A chai brewed with more leaf or simmered longer will sit higher than those tea figures; a decaf or rooibos-based chai sits lower. Our chai caffeine guide covers lattes and dirty chai.

What does research describe about cardamom?

The cardamom in chai is usually green cardamom, the pods of Elettaria cardamomum. Most of the human research on it uses concentrated supplements. A 2022 meta-analysis (Izadi and colleagues, Phytotherapy Research) pooled eight trial reports with 595 participants who had metabolic syndrome or related disorders. It found a small difference in diastolic blood pressure (about 0.91 mmHg) and in two inflammatory markers, and no significant change in systolic blood pressure, and the authors noted that the trials were few and small. A cup of chai is not a comparable dose. See cardamom benefits for the full breakdown.

How much of the ginger research applies to a cup of chai?

Very little directly, because ginger research uses measured doses. A 2006 meta-analysis (Chaiyakunapruk and colleagues) pooled five randomized trials with 363 patients that gave a fixed dose of at least 1 g of ginger around surgery. A cup of chai is not a measured dose, and we make no claim that chai treats nausea or any other condition; talk to a healthcare provider about nausea, especially during pregnancy.

What is the cinnamon in chai for?

Flavor and aroma. We make no health claim for the cinnamon in a cup of chai.

How much chai per day?

One to three cups keeps caffeine modest for most adults. At the FDA's black-tea figure of about 47 mg per 8 oz, three cups come to roughly 140 mg, well under the 400 mg a day the FDA cites for most adults as an amount not generally associated with negative effects. Stronger chai, extra shots of espresso in a dirty chai, and other caffeine sources during the day all add to that total. This is general information, not medical advice.

Who should skip chai?

• People sensitive to caffeine: try a decaf chai or a rooibos-based, caffeine-free chai.
• Anyone taking medication or managing a health condition: ask a clinician about caffeine and concentrated spices before drinking chai daily.
• If strong or spicy drinks bother your stomach: try a milder blend with less ginger and pepper.
• Anyone drinking café chai lattes as a health drink: many are heavily sweetened, so read the label for added sugar.

What does a real chai routine look like?

The traditional method simmers everything: spices in water first, then the tea brewed in with milk, and sweetener to taste. See our masala chai recipe for the full method, or the chai concentrate recipe for batch-brewing.

For a faster cup, Spice Rush is black tea milled to a powder and blended with cardamom, ginger, cinnamon and collagen peptides: one scoop (about 5 g) in 8 oz of near-boiling water, stirred, is about thirty seconds to a full cup. Background on the latte format: what is a chai latte.

The bottom line

Chai's caffeine and L-theanine come from its tea, and how much of each reaches your cup depends on the tea, how much you use and how long it brews. The spice research uses measured, concentrated doses that a cup of chai does not match. For a specific product, check the label for caffeine per serving.