White Tea Protected Sperm Where Vitamin C Did Not

White tea's effects held across every dose. Vitamin C's reversed at its higher one

A paper published in the Journal of Men's Health in January 2026 took human sperm samples, damaged them on purpose with a chemical, and then treated that damage two ways: with an aqueous extract of white tea at four concentrations¹, and with L-ascorbic acid, which is vitamin C and the standard benchmark antioxidant in this literature.

Across the doses tested, the white tea extract reduced DNA fragmentation (breaks in the sperm's genetic material), reduced oxidation-reduction potential (a sample's overall balance of oxidative stress), and reduced reactive oxygen species, the unstable molecules that cause that stress. It also raised mitochondrial membrane potential (a measure of a cell's own energy health), vitality, and motility. That is six measures moving in the same direction, each significant at p < 0.05.

Vitamin C's own record split by dose. At its lower tested concentration it increased the acrosome reaction, the structural change a sperm's head must undergo to fertilize an egg, and lowered oxidation-reduction potential. At its higher tested concentration it still raised motility and viability, but the acrosome reaction reversed, mitochondrial membrane potential fell, and DNA fragmentation rose, each significant, with no significant effect on reactive oxygen species at that point.

Why oxidative stress in sperm gets measured at all

A 2025 paper in Antioxidants, on sperm adiponectin and DNA fragmentation, states in its introduction² that approximately 50 percent of infertility cases can be attributed to a male factor, alone or in combination with a female factor, and that in 30 percent of men with infertility, an imbalance between reactive oxygen species and antioxidant defenses is considered one of the causes of idiopathic, meaning unexplained, male infertility. Those two figures are why a literature on sperm and oxidative stress exists at all.

An antioxidant applied to a sperm sample is therefore a question a laboratory can put narrowly and answer. Keep the narrowness in view for the rest of this entry.

The damage was induced on purpose, then treated at four concentrations

The samples came from normozoospermic donors, which means ordinary semen parameters, nothing already impaired. They were exposed to 100 micromolar cumene hydroperoxide at 37°C: 60 minutes for oxidation-reduction potential, reactive oxygen species, mitochondrial membrane potential, DNA fragmentation, and the acrosome reaction, and 60 to 120 minutes for motility and viability.

Cumene hydroperoxide is a laboratory tool for inducing oxidative stress in a sample so the sample can be studied. It is not something that happens to sperm in a body. The paper reports that the exposure significantly decreased the integrity of the measured seminal parameters, so the damage model did its work before any tea entered the experiment.

The white tea extract was then applied at 0.465, 4.65, 46.5, and 465 µg/mL. Bottom to top, that range spans a factor of a thousand, the kind of spread a study uses to look for a dose-response relationship rather than trust one concentration.

Seven outcomes were read: motility, viability, oxidation-reduction potential, reactive oxygen species production, mitochondrial membrane potential, sperm DNA fragmentation, and the acrosome reaction, the structural change in the sperm head that has to occur for fertilization.

Where vitamin C turned

Vitamin C helped at its lower concentration: the acrosome reaction rose and oxidation-reduction potential fell, both in the healthy direction. Pushed to its higher tested concentration, motility and viability still rose, but the acrosome reaction reversed, mitochondrial membrane potential fell, and DNA fragmentation rose.

That is a dose-dependent flip, not a flat harm, and it is reported for the ascorbic acid alone. The white tea extract is reported as beneficial across its four doses, with no reversal of that kind described.

Two figures are missing from what is available here. The abstract does not give the numeric concentration that counts as the higher one for ascorbic acid, and it gives no percentage change for any outcome; direction and statistical significance are what the paper reports at that level, and the full text was not accessible for this entry. And the paper reporting only improvements for white tea across the doses tested is not the same as the paper stating that none of the four doses had any negative effect on any measure. It does not say that, so this page does not either.

No one in this study drank tea

All of this was done in vitro. The samples sat outside a body, in a dish, under artificially induced stress, and a concentrated extract was applied directly to them. Nobody drank anything, and no living body was involved once the sample was given.

The study therefore says nothing about whether drinking white tea changes fertility, sperm quality, or any other measure in a person. It is not a dietary study, and none of the four concentrations converts into a cup. This site's health and science page sorts white tea claims into tiers by what was actually tested, cells in a dish, a live animal, or an actual person, and this result belongs in the first of those, extended to human tissue rather than a cell line.

The three white tea studies entered on this site before it were run in rats and in a fruit fly. This is the first on human tissue, and the first anywhere near fertility.

Entered as an in vitro result

The authors' own closing line calls the finding a step toward treating male infertility caused by oxidative stress. That is the study's own word, and it reaches further than one in vitro paper, seven measures, four doses, and no living body anywhere in it can carry on its own.

What the paper actually supports is narrower, and still real. In these samples, the benchmark antioxidant had a concentration at which its help came with new damage on three measures, and the white tea extract, across a thousand-fold range of doses, showed no such turn. That is what was measured. Treating anything in a person is a claim for a different kind of study, one that has not yet been run.