The indigenous people of the Amazonian have been eating the camu camu fruit for generations. Its berries grow on a shrub in the rainforests of Brazil, Columbia, Peru, and Venezuela. Since it is found next to the water (and even in shallow water) historically it was has harvested by people in canoes who would paddle along the riverbanks, seeking the bushes with their blossoming red and yellow fruits. As its popularity has increased during the past decade, it has begun to be cultivated outside of its native habitat.
Without a doubt, perhaps the primary reason it has been catapulted to superfood status is because it is the food highest in vitamin C (up to 7.5% of its weight is natural vitamin C). Perhaps the only thing that comes close is the fruit in 2nd place, the acerola cherry (up to 4.5% by weight). The foods which have the highest natural vitamin C content after those are pale in comparison: 0.22% by weight for guava, 0.18% by weight for bell peppers, and 0.12% for kale (which take places 3, 4, and 5, respectively).
As impressive as its C content is, that is only one of the camu camu health benefits which have made it famous. The vitamin C represents only a small portion of the total antioxidant power found in this fruit. Other potent antioxidants such as anthocyanins, flavonols, and ellagic acid are what gives camu camu powder such an impressive ORAC value. Other nutritional benefits include respectable amounts of the amino acids serine, leucine, and valine. The vitamins B1, B3, and beta-carotene (a carotenoid your body converts to vitamin A). Minerals including iron, calcium, potassium, and phosphorus. A study published in 2015 in the Journal of Alternative and Complementary Medicine suggested that camu camu may be a natural ingredient beneficial for conditions involving chronic-inflammation, since it demonstrates anti-inflammatory properties (1).
Where can you buy it? Camu camu berry extract or powder is the most common form you will find it. It can be picked up at your local Whole Foods or just about any natural grocer. Most people buy organic camu camu powder in bulk online because it is often times significantly cheaper than what the brick and mortar stores charge for it. Plus, since many stores categorize it as a health supplement (like a bottle of vitamins) they may charge sales tax on it, as is the case in California.
The size of the berries range from about 0.33 to 1.25 inches in diameter but you will not find those for purchase outside their native territory. Why? Because of the fruits high acidity it is extremely bitter, which doesn't lend well to using it as a fresh fruit. Not to mention, importing fresh camu camu fruit from South America would not be economically feasible, at least as of today based on current demand, since it is still a niche food which has not yet been widely adapted in North America or other parts of the world.
Research Support, Non-U.S. Gov't: Brunswick Laboratories Test Report For Amazon Origins, LLC Press Release March 2011