Take it at the very first sign of illness — that's when it can have the greatest impact on reducing both the length and severity of symptoms. Many athletes also take it daily during peak training blocks or travel-heavy periods as a preventive measure when immune function is most at risk.

Heavy training temporarily suppresses immune function — a well-documented response to physical stress sometimes called the "open window" effect. Vitamin C, D3, and zinc each deplete faster in athletes than in sedentary individuals, making supplementation especially relevant during high training load periods.

Yes. Ultra Immune C is Informed Sport Certified, meaning every batch is third-party tested for substances banned in sport. It carries the same certification standard used by most professional sports organizations.

It's a light tropical-flavored powder sweetened with stevia. Athletes consistently cite the taste as one of the reasons they stay consistent with it — it mixes easily with water or juice and doesn't taste like a supplement.