Benefits
Oxidative stress markers in healthy adults
In 18 healthy adults, protein carbonyls, a marker of protein oxidation, fell within the group drinking a purple corn cob and stevia tea twice daily for 4 weeks, but antioxidant capacity measured by one assay also fell, and the overall oxidative stress score did not change in either group. These are lab markers in a very small study.
Working memory and brain response timing in midlife women
In 30 women aged 45 to 60 around menopause, a drink with 400 mg a day of combined purple corn cob and pandan leaf extract shortened brain response timing on EEG and improved choice reaction accuracy and spatial memory speed after 1 month versus placebo. The task gains were gone by 2 months. Pandan was in the drink too, so the effect cannot be credited to corn alone.
Fasting glucose with a four-ingredient formula
In 81 adults with fasting blood sugar slightly above normal, a 3-month tablet combining purple corn extract with gymnema, zinc and chromium lowered fasting glucose and HbA1c versus placebo in one of its two dose groups. The study authors note that the corn extract has not been shown to work on its own.
Skin and blood lipid measures during radiotherapy
In 193 patients having breast radiotherapy, an anthocyanin-rich purple corn cob extract three times a day did not prevent radiation skin changes, the main outcome. A moderate radiation-linked rise in total and HDL cholesterol and triglycerides was not seen in the extract group. This is research in patients under medical care.
Blood pressure and blood sugar effects seen in rodents
In animal studies, a diet with 1% purple corn color lowered blood pressure in rats bred to have high blood pressure, and purple corn extract lowered fasting blood sugar and HbA1c in diabetic mice. None of the human studies cited here tested blood pressure, and these animal results have not been confirmed in people.
Mechanism of action
Anthocyanin pigments
Purple corn's color comes from anthocyanins, chiefly cyanidin-3-glucoside, which neutralize free radicals in laboratory tests. In people, only small changes in blood oxidation markers have been measured, and not all of them pointed the same way.
Glucose and insulin signaling in cells and mice
In cell studies, purple corn anthocyanins increased glucose-stimulated insulin secretion and liver-cell glucose uptake through the FFAR1 receptor and glucokinase. In diabetic mice, extract raised AMPK activity in the liver and GLUT4 in muscle. These are cell and animal findings.
Fat tissue inflammation in obese mice
In mice fed a high-fat diet for 12 weeks, purple corn cob extract reduced macrophage build-up in fat tissue, shifted those cells toward an anti-inflammatory type by dampening NF-kB signaling, and reduced fatty liver. This has not been measured in people.
Possible effect on platelets
The Peruvian trial authors linked the small skin bruise spots seen in some users to an anti-platelet effect of purple corn, citing earlier local studies. This is the authors' explanation; platelet function was not measured in the trial.
Clinical trials
Food science study of a purple corn cob and stevia tea, combining storage-stability testing with a 4-week consumption study against a control group. (Díaz-García et al. 2025, Food Res Int)
18 healthy men and women aged 18 to 45 with normal body weight (BMI 19 to 25.5), split into a tea group (twice daily) and a control group.
In the tea group, protein carbonyls fell after 2 weeks and ORAC-PGR, an antioxidant-capacity assay, fell after 4 weeks. These were changes within the tea group, not differences from the control group. The combined OXY-SCORE oxidative stress index did not change significantly in either group. Very small study of lab markers only.
Single-center, randomized, double-blind, placebo-controlled crossover trial in Thailand of the drink MP1, a combined extract of purple waxy corn cob and pandan leaf, with 2-week washout. (Wattanathorn et al. 2025, Antioxidants (Basel))
32 eligible peri- and postmenopausal women aged 45 to 60 (30 analyzed), taking 400 mg/day of the combined extract (about 4 mg anthocyanins per serving) or placebo for 2 months.
Brain response timing (N100 and P300 latency) shortened versus placebo at 1 and 2 months and was back to placebo levels 1 month after stopping. Choice reaction accuracy and spatial memory speed improved at 1 month but not at 2 months or after stopping. MDA fell and SOD rose; AChE and MAO did not change. No serious adverse events. The drink also contained pandan.
Monocentric, randomized, double-blind, placebo-controlled 3-month trial in Italy of a multi-ingredient food supplement containing a purple corn extract (Moradyn), gymnema extract, zinc and chromium. (Buccato et al. 2024, Nutrients)
81 adults aged 18 to 75 with fasting blood glucose of 98 to 125 mg/dL, 27 per group (two supplement doses and placebo).
Fasting glucose and HbA1c fell versus placebo in the group the authors call group 1; the abstract and methods disagree on whether that group took one or two tablets. Insulin, HOMA-IR and blood lipids did not differ. No kidney or liver toxicity was seen. Purple corn was one of four active ingredients.
Randomized, double-blind, placebo-controlled trial of an anthocyanin-rich corn cob extract three times daily from 1 week before until the end of radiotherapy; a later ATHENA paper identifies the source as purple corn cob. (Bracone et al. 2021, Clin Nutr)
193 women with breast cancer having 3- or 5-week radiotherapy in Italy (97 extract, 96 placebo).
The extract did not prevent radiotherapy skin changes, the main outcome; skin measures changed alike in both groups. A moderate radiotherapy-linked rise in total and HDL cholesterol and triglycerides was prevented in the extract group. Supplementation was well tolerated.
Single-blind, placebo-controlled trial in the authors' private gastroenterology practices in Lima, Peru, of a freeze-dried purple corn concentrate (Vidafenol), 200 mg once daily, self-funded, published in Spanish. (Ichiyanagui et al. 2021, Rev Gastroenterol Peru)
224 adults aged 21 to 87 who had colon polyps removed within the previous 30 days (112 per group); people who missed the 3-year colonoscopy or took the product less than half the time were excluded.
At 3 years, 16.1% of the purple corn group had polyps again versus 99.1% of the placebo group (p<0.001), which the authors describe as 83% fewer polyps. Adverse events were reported by 4.5% of each group: petechiae in 4 of 112 on purple corn and headache, bloating or diarrhea on placebo. Single blinding, groups matched by age, sex and BMI where possible, a completers-only analysis and the very high placebo recurrence limit confidence.