Sea buckthorn is widely cited as one of the more concentrated natural sources of vitamin C — but the way the vitamin arrives inside the whole fruit is at least as interesting as the number on the label.
Sea buckthorn is widely cited in food-science literature as one of the more concentrated natural sources of vitamin C. Published composition surveys of Hippophae rhamnoides (including reviews in Molecules, Food Chemistry and the Journal of Food Science and Technology) report values ranging from around 400 mg to as much as 1,500 mg of vitamin C per 100 g of fresh berry, depending on cultivar, altitude and season. An average orange sits closer to 50 mg per 100 g — so the popular shorthand "up to ~10× an orange" refers to the higher end of that reported range for wild Himalayan varieties, not a fixed number for every batch.
What makes sea buckthorn's vitamin C behave differently on the tongue is its companion chemistry. It arrives alongside flavonoids (quercetin, kaempferol, isorhamnetin) that laboratory studies suggest may help stabilise vitamin C, and it is buffered by the fruit's own minerals rather than a pure ascorbic-acid solution. The result, in a glass, is a food-matrix vitamin C — one entry point among many for a nutrient the body draws on across everyday processes.