What Actually Ends Up in the Cup: A Look at Tea Extraction Studies

Steeping dried leaves in hot water is a simple act, but it is also a chemical extraction process, and not every compound in a leaf makes the jump into the water at the same rate. A 2025 laboratory study set out to measure exactly what does and does not transfer from Artemisia annua leaf into an infusion, comparing tea made from plants grown in two very different places.

The setup

Researchers prepared herbal teas using A. annua grown at ten different plantations in Benin and at one location in southern France, then analyzed the resulting infusions with liquid chromatography and mass spectrometry, techniques that separate and identify individual chemical compounds in a mixture (Aubouy et al., 2025). Because this research was specifically studying antiplasmodial activity, meaning activity against the parasite that causes malaria, in a laboratory culture of Plasmodium falciparum, the study also measured that lab-based biological effect alongside the plain chemical measurements. It is worth being clear that this is a laboratory finding about parasite cultures in a dish, not a clinical study of people drinking tea, and it says nothing about any product sold as a food.

What the numbers showed

The measured artemisinin content in the infusions varied enormously, from as little as 0.3 milligrams per liter in tea from the French-grown plants to as much as 15.7 milligrams per liter in some of the Benin-grown batches, a more than fifty-fold difference depending entirely on where and how the source plant was grown. The study also found that artemisinin levels dropped measurably after a year of storing the dried plant material, with losses of 24 to 48 percent recorded across different batches, underlining that dried herb chemistry is not static on the shelf either.

Interestingly, the laboratory antiplasmodial activity of the teas correlated with, but was not fully explained by, artemisinin content alone. The researchers detected several other compounds in the extracts, including chlorogenic acid, a common plant polyphenol, and some unidentified alkaloids, that appeared statistically linked to the measured lab activity, suggesting hot water pulls out more than a single active ingredient.

Why extraction, specifically, is the interesting part

The core scientific contribution here is methodological: this study is one of relatively few to directly measure what a household-style water infusion, not a solvent-based laboratory extraction, actually delivers from this plant, and to show that the answer depends heavily on growing conditions and storage time. That is a useful, sobering data point for anyone assuming that "tea" is a single, standardized extraction method. It plainly is not.

This article reports published laboratory research on the plant and its extraction into water infusions. It is not medical advice, and our tea is sold as a food product, not a medicine.