A 312-person trial found elderberry cut cold duration by two days, but this popular immune supplement also packs a vitamin D3 dose over the adult safety limit.
vitamin D3
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Vitamin D3: Why a Popular 5,000 IU Dose Tops the NIH's Limit
NIH caps adult vitamin D at 4,000 IU (100 mcg) a day, yet a popular 5,000 IU softgel sells at 625% of the Daily Value. Here's what the trial evidence actually shows.