# Calcium Ascorbate Anhydrous

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/calcium-ascorbate-anhydrous
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-04
**Evidence Score:** 2 / 10
**Category:** Mineral
**Also Known As:** Calcium L-ascorbate anhydrous, Calcium salt of ascorbic acid anhydrous, Vitamin C calcium salt, Buffered vitamin C, Mineral ascorbate, Calcium ascorbic acid, C₁₂H₁₄CaO₁₂, Non-acidic vitamin C

## Overview

Calcium ascorbate anhydrous is a mineral salt of ascorbic acid (vitamin C) delivering approximately 90% ascorbic acid and 10% elemental calcium in a water-free, buffered form. It functions as a non-acidic antioxidant that donates electrons to neutralize [reactive oxygen species](/ingredients/condition/antioxidant) while supporting collagen biosynthesis via prolyl and lysyl hydroxylase enzyme activation.

## Health Benefits

• Provides buffered vitamin C (90% content) for [antioxidant](/ingredients/condition/antioxidant) support without gastric irritation - evidence quality: theoretical based on composition
• Supplies elemental calcium (10% content) for [bone health](/ingredients/condition/bone-health) support - evidence quality: theoretical based on composition
• Supports [collagen production](/ingredients/condition/skin-health) and tissue interstitial matrix formation - evidence quality: mechanistic understanding only
• Aids in [neurotransmitter](/ingredients/condition/cognitive) synthesis and amino acid [metabolism](/ingredients/condition/weight-management) - evidence quality: mechanistic understanding only
• Enhances [immune function](/ingredients/condition/immune-support) through vitamin C activity - evidence quality: inferred from general vitamin C properties

## Mechanism of Action

Ascorbic acid from calcium ascorbate acts as a cofactor for prolyl-4-hydroxylase and lysyl hydroxylase, enzymes essential for hydroxylating proline and lysine residues during collagen triple-helix stabilization. The ascorbate anion also regenerates oxidized alpha-tocopherol (vitamin E) and directly scavenges superoxide, hydroxyl radicals, and singlet oxygen, reducing [oxidative stress](/ingredients/condition/antioxidant) markers such as 8-isoprostane. The calcium component dissociates in solution and is absorbed via TRPV6 calcium channels and the paracellular route in the small intestine, contributing to intracellular signaling and hydroxyapatite mineralization in bone.

## Clinical Summary

Direct clinical trials on calcium ascorbate anhydrous as a distinct form are sparse; most evidence is extrapolated from studies on ascorbic acid and calcium supplementation independently. Vitamin C research, including a Cochrane review of over 30 trials, demonstrates that gram-level ascorbic acid supplementation reduces common cold duration by approximately 8% in adults. Buffered vitamin C forms like calcium ascorbate are theorized to reduce gastrointestinal distress compared to ascorbic acid, but head-to-head randomized controlled trials confirming superior GI tolerability at matched doses are limited. The calcium contribution (~100 mg elemental calcium per 1,000 mg supplement) is modest relative to the 1,000–1,200 mg daily recommended intake, making it a supplementary rather than primary calcium source.

## Nutritional Profile

Calcium Ascorbate Anhydrous is a mineral salt form of vitamin C with a precise compositional profile: approximately 890-910 mg ascorbic acid equivalent per gram (89-91% w/w ascorbate ion) and approximately 100-114 mg elemental calcium per gram (10-11.4% w/w calcium). As an anhydrous form, it contains no bound water molecules, yielding a higher active compound density compared to the monohydrate form. It is a pure compound with no macronutrient content (zero protein, fat, or carbohydrate in functional quantities). The primary bioactive compounds are the ascorbate anion (the biologically active form of vitamin C) and calcium cation. Bioavailability notes: The buffered pH (approximately 6.8-7.4 in solution) makes it less acidic than pure ascorbic acid, potentially improving gastric tolerance at higher doses; ascorbate bioavailability is comparable to ascorbic acid at standard doses (approximately 70-90% absorption at doses under 200 mg), declining with increasing dose due to saturation of sodium-dependent vitamin C transporters (SVCT1, SVCT2). Calcium bioavailability from this form is estimated at 25-35%, consistent with other soluble calcium salts, and is absorption-dependent on vitamin D status, gastric acid presence, and co-ingestion of competing divalent minerals (e.g., zinc, iron, magnesium). No dietary fiber, no phytochemicals, no lipid-soluble vitamins present.

## Dosage & Preparation

No clinically studied dosage ranges for calcium ascorbate anhydrous are detailed in the available research. The compound provides approximately 10% elemental calcium and 90% vitamin C by weight, and is often used as a food additive without quantified therapeutic standardization. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Calcium ascorbate anhydrous is generally well tolerated, but doses of ascorbic acid exceeding 2,000 mg/day (the established Tolerable Upper Intake Level) may cause osmotic diarrhea, nausea, and kidney oxalate stone formation in susceptible individuals. The calcium component can interact with bisphosphonates (e.g., alendronate), levothyroxine, and certain fluoroquinolone antibiotics by reducing their absorption when co-administered; a 2-hour separation is recommended. High-dose vitamin C may interfere with warfarin anticoagulation and can falsely lower [blood glucose](/ingredients/condition/weight-management) readings on certain glucometer test strips. Calcium ascorbate is considered low-risk during pregnancy at doses within the 85–120 mg/day ascorbic acid RDA, though megadose supplementation should be avoided without medical supervision.

## Scientific Research

The research dossier reveals no specific human clinical trials, RCTs, or meta-analyses on calcium ascorbate anhydrous. No PubMed PMIDs are provided in the available literature. General literature on ascorbate salts implies equivalent efficacy to ascorbic acid due to similar bioavailability, but no dedicated studies are cited.

## Historical & Cultural Context

No historical or traditional medicine uses are documented in the research for calcium ascorbate anhydrous. It is primarily a modern synthetic compound developed for use as a food additive and dietary supplement. The compound lacks traditional usage in systems like Ayurveda or TCM.

## Synergistic Combinations

Bioflavonoids, Vitamin D3, Magnesium, Zinc, Collagen peptides

## Frequently Asked Questions

### What is the difference between calcium ascorbate anhydrous and regular ascorbic acid?

Calcium ascorbate anhydrous is a calcium salt of ascorbic acid with the water molecules removed, yielding approximately 90% ascorbic acid and 10% elemental calcium by weight, compared to pure ascorbic acid which has a pH around 2.5. The buffered, near-neutral pH of calcium ascorbate (approximately pH 7.0 in solution) reduces direct acid exposure to the gastric lining, making it a preferred option for individuals with acid reflux or sensitive stomachs. However, once absorbed, both forms deliver the same bioactive ascorbate anion to tissues.

### How much elemental calcium does calcium ascorbate anhydrous provide?

Calcium ascorbate anhydrous contains approximately 10% elemental calcium by molecular weight, meaning a 1,000 mg dose delivers roughly 100 mg of elemental calcium. This is meaningful but represents only about 8–10% of the adult daily recommended intake of 1,000–1,200 mg, so it should not be relied upon as a standalone calcium source for bone health. It is best viewed as a complementary source when the primary goal is vitamin C supplementation.

### Is calcium ascorbate anhydrous better absorbed than other vitamin C forms?

Bioavailability studies, including a 2013 comparison published in Nutrients, suggest that ascorbate absorption is similar across most oral vitamin C forms at doses below 200 mg, as intestinal sodium-dependent vitamin C transporters (SVCT1 and SVCT2) become saturated at higher intakes. Calcium ascorbate has not demonstrated statistically superior plasma ascorbate levels over ascorbic acid in controlled pharmacokinetic trials. The primary advantage is tolerability rather than enhanced absorption efficiency.

### What is the recommended dosage of calcium ascorbate anhydrous for immune support?

The RDA for vitamin C is 75–90 mg/day for adults, with the Tolerable Upper Intake Level set at 2,000 mg/day of ascorbic acid equivalents. For immune support, commonly studied supplemental doses range from 500 mg to 1,000 mg of ascorbic acid equivalent per day, which would correspond to approximately 555–1,111 mg of calcium ascorbate anhydrous. Doses should be split across meals to optimize intestinal absorption and minimize the risk of osmotic diarrhea.

### Can calcium ascorbate anhydrous cause kidney stones?

High-dose ascorbic acid supplementation above 1,000 mg/day can increase urinary oxalate excretion, since ascorbate is partially metabolized to oxalate in the liver, raising the theoretical risk of calcium oxalate kidney stones in predisposed individuals. A prospective study in the Journal of Urology found that men taking 1,000 mg/day of supplemental vitamin C had a 41% higher risk of kidney stones compared to non-supplementers. Individuals with a history of kidney stones, hyperoxaluria, or renal impairment should consult a physician before using high-dose calcium ascorbate anhydrous.

### Does calcium ascorbate anhydrous interact with iron supplements or medications?

Calcium ascorbate anhydrous may reduce iron absorption when taken simultaneously, as calcium can inhibit iron uptake in the digestive tract. If you take iron supplements or iron-based medications, separate your calcium ascorbate anhydrous dose by at least 2 hours to minimize this interaction. Always consult your healthcare provider before combining these supplements, especially if you have iron deficiency or anemia.

### Who benefits most from calcium ascorbate anhydrous supplementation?

Calcium ascorbate anhydrous is particularly beneficial for individuals who need vitamin C support but have sensitive stomachs, as the buffered formula reduces gastric irritation compared to acidic ascorbic acid. It may also appeal to those seeking combined vitamin C and calcium supplementation for joint health, wound healing, and bone support simultaneously. People with high oxidative stress or compromised immune function may benefit from its antioxidant properties.

### How does the anhydrous form of calcium ascorbate differ from other calcium ascorbate formulations?

The anhydrous form contains no water molecules in its crystal structure, making it more concentrated and shelf-stable compared to calcium ascorbate dihydrate formulations. This means anhydrous versions deliver a higher amount of active ingredient per gram and may have improved storage longevity in humid environments. The anhydrous form also typically has better flowability for manufacturing, potentially making it easier to include in capsule and tablet formulations.

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