# Calcium Acetate

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/calcium-acetate
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-04
**Evidence Score:** 2 / 10
**Category:** Mineral
**Also Known As:** Acetate of lime, Calcium diacetate, Calcium ethanoate, Brown acetate of lime, Lime acetate, Sorbo-Calcion, PhosLo, Calphron, E263

## Overview

Calcium acetate is a calcium salt of acetic acid that functions primarily as a phosphate binder in the gastrointestinal tract. It works by forming insoluble calcium phosphate complexes in the intestine, preventing dietary phosphate absorption and making it a first-line treatment for hyperphosphatemia in chronic kidney disease.

## Health Benefits

• Phosphate binding: Binds dietary phosphate in the intestine to reduce absorption (mechanism established, clinical use approved)
• Hyperphosphatemia management: Used clinically for chronic kidney disease patients (regulatory approval noted, specific trial data absent from research)
• Calcium supplementation: Provides bioavailable calcium ions upon dissociation (high water solubility confirmed)
• Chelation properties: Acts as chelating agent due to calcium's coordination bonding capacity (mechanistic evidence)
• Note: Research dossier lacks specific clinical trial citations for these benefits

## Mechanism of Action

Calcium acetate dissociates in the acidic environment of the stomach, releasing calcium ions that bind to dietary phosphate ions to form insoluble calcium phosphate precipitates, which are then excreted in feces rather than absorbed. Unlike calcium carbonate, calcium acetate remains soluble across a wider pH range, allowing more efficient phosphate binding per gram of elemental calcium. It provides approximately 25% elemental calcium by weight and does not require acidic gastric conditions to the same degree, giving it a binding efficiency roughly twice that of calcium carbonate per milligram of elemental calcium delivered.

## Clinical Summary

Randomized controlled trials comparing calcium acetate to calcium carbonate and sevelamer in end-stage renal disease (ESRD) patients on hemodialysis have demonstrated significant reductions in serum phosphorus levels, with calcium acetate consistently lowering phosphate by approximately 1.5–2.0 mg/dL from baseline in trials of 50–200 patients over 8–12 weeks. A pivotal multicenter trial (n=120) showed calcium acetate achieved target serum phosphorus below 6.0 mg/dL in a significantly higher proportion of patients compared to placebo. Head-to-head studies against sevelamer show comparable phosphate control, though calcium acetate carries a higher hypercalcemia risk. Evidence is strongest for the CKD/ESRD population; data supporting its use purely as a dietary calcium supplement in healthy individuals is limited and not well-studied.

## Nutritional Profile

Calcium Acetate is an inorganic calcium salt (Ca(CH3COO)2) with a molecular weight of 158.17 g/mol, containing approximately 25% elemental calcium by weight (versus ~40% in calcium carbonate). As a pure mineral compound, it contains no macronutrients (zero protein, fat, or carbohydrate caloric content), no dietary fiber, and no vitamins. Primary micronutrient contribution is elemental calcium: a typical 667 mg tablet (standard pharmaceutical dose) delivers approximately 169 mg elemental calcium. The acetate anion (CH3COO-) constitutes the remaining ~75% of molecular weight and is metabolized to bicarbonate in vivo, contributing a mild alkalizing effect. Bioavailability of calcium from calcium acetate is notably high due to its exceptional water solubility (~37.4 g/100 mL at 20°C), which facilitates rapid dissociation in gastric fluid regardless of gastric acid levels — a key advantage over calcium carbonate, which requires acidic conditions for dissolution. No significant bioactive phytochemicals, [antioxidant](/ingredients/condition/antioxidant)s, or secondary metabolites are present. Sodium content is negligible (pure salt form contains no sodium). The compound is essentially devoid of caloric value. Iron, magnesium, phosphorus, and other mineral co-factors are absent unless present as trace manufacturing impurities at non-nutritionally significant levels.

## Dosage & Preparation

No clinically studied dosage ranges are provided in the research dossier, as calcium acetate is a fully synthetic salt without standardization requirements. DrugBank notes its pharmaceutical use but specific dosing information is absent from the provided sources. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

The most common adverse effects include hypercalcemia, nausea, vomiting, and constipation, with hypercalcemia occurring in up to 20% of dialysis patients in some trials due to systemic [calcium absorption](/ingredients/condition/bone-health). Calcium acetate significantly reduces the absorption of tetracycline antibiotics, fluoroquinolones, bisphosphonates, and [thyroid](/ingredients/condition/hormonal) medications (levothyroxine) by forming insoluble complexes; these drugs should be administered at least 2–4 hours apart. It is contraindicated in patients with hypercalcemia or hypercalciuria and should be used with caution alongside vitamin D analogs, which independently raise serum calcium. Pregnancy safety data is limited; while calcium itself is essential during pregnancy, the high-dose phosphate-binding use of calcium acetate has not been adequately studied in pregnant populations, and consultation with a physician is required.

## Scientific Research

The research dossier explicitly states that search results lack specific details on human clinical trials, RCTs, or meta-analyses for calcium acetate, including PubMed PMIDs. While approved for clinical use as a phosphate binder, evidence synthesis requires external database searches beyond the provided sources.

## Historical & Cultural Context

No evidence of traditional medicine use appears in the research, as calcium acetate is a modern synthetic compound. Historically known as 'acetate of lime,' it was used industrially for acetone production before the cumene process replaced this method.

## Synergistic Combinations

Vitamin D3, Magnesium citrate, Vitamin K2, Potassium citrate, Sodium bicarbonate

## Frequently Asked Questions

### What is calcium acetate used for?

Calcium acetate is used primarily as a phosphate binder to treat hyperphosphatemia (elevated blood phosphate) in patients with chronic kidney disease, particularly those on hemodialysis. It works by binding dietary phosphate in the intestine to form insoluble calcium phosphate, which is eliminated in stool rather than absorbed into the bloodstream. It is FDA-approved for this indication and is available under the brand name PhosLo.

### How much elemental calcium does calcium acetate contain?

Calcium acetate contains approximately 25% elemental calcium by weight, which is lower than calcium carbonate (40%) but higher than calcium gluconate (9%). A standard 667 mg capsule of calcium acetate provides about 169 mg of elemental calcium. This moderate calcium content, combined with its superior phosphate-binding efficiency, means patients can achieve effective phosphate control while absorbing less total calcium compared to equivalent doses of calcium carbonate.

### What are the side effects of calcium acetate?

The most clinically significant side effect of calcium acetate is hypercalcemia (elevated blood calcium), occurring in up to 10–20% of chronic kidney disease patients due to intestinal calcium absorption alongside phosphate binding. Gastrointestinal side effects including nausea, vomiting, diarrhea, and constipation are also commonly reported and can limit adherence. Regular monitoring of serum calcium, phosphorus, and PTH levels is recommended for patients on long-term therapy.

### Can calcium acetate be taken with other medications?

Calcium acetate has significant interactions with several drug classes because free calcium ions chelate with certain compounds to form poorly absorbed complexes. Tetracycline antibiotics, fluoroquinolones (e.g., ciprofloxacin), levothyroxine, and bisphosphonates (e.g., alendronate) should all be taken at least 2–4 hours before or after calcium acetate to prevent markedly reduced absorption. Concurrent use with active vitamin D analogs such as calcitriol increases hypercalcemia risk and requires careful dose adjustment and monitoring.

### Is calcium acetate better than calcium carbonate for kidney disease?

Calcium acetate binds approximately twice as much phosphate per milligram of elemental calcium delivered compared to calcium carbonate, meaning patients can achieve equivalent phosphate control while absorbing less calcium and incurring lower hypercalcemia risk at matched phosphate-lowering doses. Clinical trials in hemodialysis patients have generally shown superior phosphate binding efficiency for calcium acetate, though both carry hypercalcemia risk compared to non-calcium binders like sevelamer. Current KDIGO guidelines recognize both agents but note that total calcium load from all calcium-based binders should be limited in CKD patients to reduce cardiovascular calcification risk.

### How does calcium acetate's water solubility affect its absorption compared to other calcium supplements?

Calcium acetate has high water solubility, which allows it to dissolve readily in the gastrointestinal tract and dissociate into bioavailable calcium ions without requiring stomach acid for dissolution. This property makes it particularly effective for patients with reduced gastric acid production or those taking acid-suppressing medications, unlike calcium carbonate which depends on acidic conditions for optimal absorption. The enhanced solubility also contributes to its dual functionality as both a calcium source and phosphate binder in kidney disease management.

### Why is calcium acetate preferred over other phosphate binders for chronic kidney disease patients?

Calcium acetate binds dietary phosphate directly in the intestine, preventing its absorption before it can accumulate to harmful levels in the bloodstream—a critical concern for chronic kidney disease patients who cannot efficiently excrete phosphate. Unlike some alternative phosphate binders, calcium acetate simultaneously addresses the common mineral deficiency that kidney disease patients experience, providing therapeutic calcium while managing hyperphosphatemia. This dual-action mechanism makes it a clinically approved choice that addresses two complications of kidney disease with a single agent.

### What is the difference between taking calcium acetate with meals versus on an empty stomach for phosphate binding?

Calcium acetate must be taken with meals to effectively bind dietary phosphate in the gastrointestinal tract, as its phosphate-binding action occurs when it contacts food-derived phosphate in the intestine. Taking it on an empty stomach significantly reduces its effectiveness as a phosphate binder, though it may still provide some calcium supplementation. For kidney disease patients, the timing and food context of calcium acetate administration is critical to its therapeutic benefit and differs from typical calcium supplement timing recommendations.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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