Here's a fun fact: unlike most animals, humans can't make vitamin C in our own bodies, so we have to get it from food or supplements. Shop for a vitamin C supplement and you'll see "ascorbic acid", "whole food vitamin C", "acerola" and "organic" on different labels. So is organic vitamin C better than synthetic? Here's what the science actually says.
How much vitamin C do you need?
The recommended daily amount for adults is 90 mg for men and 75 mg for women, with an extra 35 mg a day for people who smoke. The upper limit for adults is 2,000 mg a day. Most people can reach the recommendation through fruit and vegetables: citrus, kiwi, strawberries, bell peppers, broccoli and Brussels sprouts are all good sources.
Vitamin C supports normal immune function, but it isn't a shield. A Cochrane review of the research found that taking vitamin C regularly did not reduce how often people in the general population caught colds, although it shortened colds slightly (by about 8% in adults). It did roughly halve the risk in people under heavy physical stress, such as marathon runners and soldiers in subarctic conditions.
How is synthetic vitamin C made?
Most vitamin C in supplements and fortified foods is ascorbic acid made industrially. Production starts with sugars such as glucose and uses a combination of fermentation and chemical steps; the older Reichstein process is increasingly being replaced by fermentation-based methods. The finished product is pure ascorbic acid.
Is natural vitamin C better than synthetic?
Molecule for molecule, no. Synthetic and food-derived vitamin C are chemically identical. When researchers compared them in people, every steady-state study found no difference in how well the body absorbs and uses them. Some short-term studies found small, temporary differences that are unlikely to matter. Animal studies were more mixed, which is where many of the "natural is better" claims come from.
What whole foods do offer is everything that comes with the vitamin C: fiber, other vitamins and minerals, and plant compounds such as flavonoids, which have their own antioxidant activity. That's a good reason to eat your fruit and vegetables, not evidence that the vitamin C itself works differently.
What is acerola, and why is it used?
Acerola is a small tropical cherry and one of the richest natural sources of vitamin C, with roughly 1,500 to 4,500 mg per 100 g of fruit, about 50 to 100 times as much as an orange or lemon. It also contains carotenoids, phenolics, anthocyanins and flavonoids. That concentration is what makes it practical to get meaningful vitamin C from a food-based ingredient.
Thirst Aid, our electrolyte drink mix, uses organic acerola cherry extract to provide vitamin C. And Aloe Gorgeous pairs vitamins C and E with aloe vera and bamboo silica to support your body's own collagen production. Read more about how vitamin C helps your body make collagen.
How can you tell where the vitamin C in a supplement comes from?
- Read the Supplement Facts panel. Many brands list the source next to the nutrient, for example "from organic acerola extract". "Ascorbic acid" or a mineral ascorbate means it was made industrially.
- Understand the organic seal. A product labeled "organic" with the USDA seal must contain at least 95% organic ingredients, so not necessarily 100%. Synthetic ascorbic acid is also on the list of nonorganic substances allowed in organic processed products.
- Ask. If the source isn't clear, contact the brand. A good company will give you a straight answer.
Can you take too much vitamin C?
Very high doses can cause stomach upset and diarrhea, which is why the adult upper limit is 2,000 mg a day. In a large study of Swedish men, regular use of vitamin C supplements was linked with a higher rate of kidney stones. If you have a history of kidney stones, kidney disease or hemochromatosis, or you take medication, talk to your doctor before taking high-dose vitamin C. For most people, food plus a modest supplement is plenty.
Want more on antioxidants in general? Read what antioxidants are and what they do.
