Also known as: D-sorbitol, glucitol
Sorbitol
Sourced from FDA-approved package inserts (DailyMed). Last verified: 2026-07-07.
What It Is & Why It's in Vaccines
Sorbitol is a sugar alcohol (polyol) used as a stabilizer and osmolyte in pharmaceutical preparations. It is naturally present in many fruits and is widely used as a food additive and sugar substitute.
Stabilizer — sorbitol protects protein antigens from denaturation during lyophilization (freeze-drying) and storage. It functions as a cryoprotectant and lyoprotectant, maintaining the three-dimensional structure of vaccine antigens.
Dose-in-Context
Per-Dose Quantity
Variable by product (typically 10–20 mg per dose in products that list it). For reference, a sugar-free cough drop may contain 1–2 grams of sorbitol — approximately 100 times more than a vaccine dose.
Reference Comparison
Sorbitol is a GRAS (Generally Recognized As Safe) food additive. It is incompletely absorbed from the GI tract and is fermented by colonic bacteria — the well-known GI effects of sorbitol (bloating, diarrhea) occur at oral doses of 10–50 grams, approximately 1,000–5,000 times higher than vaccine doses, and are not relevant to the injected route.
Source: FDA 21 CFR 184.1835 (Sorbitol as a direct food substance affirmed as GRAS).
Route-of-Administration Note
Injected route. Sorbitol administered parenterally at these trace quantities is rapidly distributed and metabolized via the polyol pathway to fructose. No specific parenteral safety concerns at vaccine-dose levels are documented.
Documented Adverse Effects
No established adverse effects have been attributed to sorbitol in vaccines at the quantities present. Sorbitol is considered one of the most benign stabilizer choices.
Individuals with hereditary fructose intolerance (HFI) — a rare autosomal recessive disorder of fructose metabolism — lack functional aldolase B and cannot metabolize fructose or sorbitol. The parenteral administration of sorbitol-containing products to individuals with HFI has been associated with severe hypoglycemia and liver failure in isolated case reports involving much larger sorbitol loads (e.g., IV sorbitol infusions). The relevance to microgram-to-milligram vaccine-stabilizer quantities is unknown, and no specific vaccine-sorbitol adverse events have been reported in HFI patients. This intersection of a rare genetic condition with vaccine-stabilizer doses is not well-studied.
Vaccines Containing Sorbitol
MMR — M-M-R II (Merck Sharp & Dohme LLC)
Live attenuated; no adjuvant. Product contains no preservative.
MMR — PRIORIX (GlaxoSmithKline Biologicals)
Contains no gelatin — relevant for gelatin allergy. Residual ovalbumin possible from chick-embryo manufacture.
Yellow Fever — YF-VAX (Sanofi Pasteur)
ⓘ Methodology Disclaimer: Ingredient lists are sourced from official FDA-approved package inserts for the specific branded products named on each vaccine page. Formulations can change between manufacturing lots and over time — always verify against the current package insert before making a clinical decision. The presence of a substance in a vaccine does not by itself indicate harm; toxicology is dose-, route-, and context-dependent. Comparisons to reference exposure levels are provided with their sources where available, and are approximate — see the cited source for full methodology.