Where Does Vitamin C in Tablets Come From?

January 9, 2026 •

2 min read

Over 90% of the world's synthetic ascorbic acid is produced in China, a process that explains where does vitamin C in tablets come from for the vast majority of supplements today. While chemically identical to natural vitamin C, the industrial process differs greatly from simply squeezing oranges.

Quick Summary

The majority of vitamin C in tablets is synthetic, derived from glucose found in corn starch through a large-scale, two-step fermentation process. This contrasts with a small market segment sourced directly from whole fruits like acerola cherries or rose hips.

Key Points

Synthetic Origin: The vast majority of vitamin C in tablets is synthesized in labs, typically using a two-step fermentation process.
Corn Starch Base: The synthetic process often starts with glucose, which is primarily derived from corn starch or other starchy crops.
Chemically Identical: Synthetic L-ascorbic acid is chemically and functionally the same as the vitamin C found in fruits.
Natural Alternative: Premium supplements may use concentrated extracts from whole fruits like acerola cherries or camu camu.
Pill Formation: The pure ascorbic acid powder is mixed with binders, lubricants, and disintegrants before being compressed into tablets.
Comparable Absorption: Human studies show no significant difference in how the body absorbs synthetic versus food-derived L-ascorbic acid.

The Dominant Source: Synthetic Manufacturing

For nearly a century, the primary source for vitamin C in tablets has been large-scale industrial manufacturing. The active compound, L-ascorbic acid, is synthesized in a multi-step process, most commonly starting with glucose derived from starchy crops such as corn or wheat. This synthetic L-ascorbic acid is chemically identical to natural vitamin C and functions the same way in the body.

The Two-Step Fermentation Process

Modern production largely relies on a two-step fermentation method, particularly prevalent in China. This process converts D-glucose to D-sorbitol, then uses bacteria like Gluconobacter oxydans for the first fermentation to produce L-sorbose. A second fermentation with microorganisms such as Ketogulonicigenium vulgare converts L-sorbose into 2-keto-L-gulonic acid (2-KLG), which is then chemically converted to L-ascorbic acid. This method is efficient and cost-effective, making synthetic L-ascorbic acid the standard for most supplements.

The Journey from Powder to Pill: Tablet Formulation

After manufacturing, ascorbic acid powder is formulated with excipients to create tablets. This involves granulation with binders, blending with lubricants and disintegrants, and compression into solid tablets. Some tablets may be coated for stability or easier swallowing.

The Other Option: Natural, Whole-Food Sources

A smaller market segment offers vitamin C from concentrated fruit and plant extracts. Common sources include acerola cherries, camu camu, rose hips, and amla. These natural supplements contain L-ascorbic acid within a food matrix including phytonutrients. While some believe these cofactors offer enhanced benefits, human studies indicate equivalent absorption and function between synthetic and natural forms.

Comparison of Synthetic vs. Natural Vitamin C Tablets


Feature	Synthetic Vitamin C (Tablets)	Natural Vitamin C (Tablets)
Raw Material	Glucose (typically from corn or wheat starch)	Whole fruits and plants (e.g., acerola, rose hips)
Production	Multi-step fermentation and chemical synthesis	Extraction and concentration of whole-food sources
Cost	Relatively low due to high-efficiency mass production	Higher, due to expensive raw materials and processing
Molecular Form	Pure, isolated L-ascorbic acid	L-ascorbic acid as part of a complex food matrix
Bioavailability	Proven and equivalent to natural sources in humans	Proven and equivalent to synthetic sources in humans in humans
Additional Nutrients	No other vitamins, minerals, or cofactors	Contains other phytonutrients like bioflavonoids
Primary Market	Dominates the supplement market	Niche, premium market

Conclusion: The Manufacturing Journey of Your Supplement

Most vitamin C tablets originate from industrial synthesis using glucose from starchy plants, not fruits. This synthetic L-ascorbic acid is then formulated with other ingredients and compressed into tablets. While natural alternatives from whole-food concentrates exist, the L-ascorbic acid itself is chemically the same regardless of source, with equivalent absorption in the body. Additional information on supplemental forms is available from the Linus Pauling Institute.

Frequently Asked Questions

For most major supplement brands, the vitamin C in tablets is synthetic, though it is chemically identical to the naturally occurring form.

Synthetic vitamin C is primarily made from glucose, a sugar typically sourced from corn starch. This glucose is processed through a two-step fermentation method.

No, human studies have shown that synthetic and food-derived L-ascorbic acid have comparable bioavailability, meaning the body absorbs and utilizes them the same way.

Natural vitamin C supplements are made from concentrated extracts of vitamin C-rich whole foods, such as acerola cherries, camu camu, or rose hips.

Calcium ascorbate is a buffered mineral salt form of vitamin C. It is less acidic than pure ascorbic acid, making it a gentler option for individuals with sensitive stomachs.

Extracting and purifying vitamin C from fresh oranges on a large scale is far less cost-effective and efficient than the industrial fermentation process.

Ascorbic acid powder is mixed with excipients like binders, fillers, and lubricants to form granules. These granules are then compressed under high pressure to form a solid tablet.