What are the quantities (mg/µg) of each ingredient in a single Comirnaty (Pfizer-BioNTech) dose?

1. What the official labels say — exact per‑dose masses

Regulatory and manufacturer labeling for the 2025–2026 Comirnaty formula gives explicit masses for the active ingredient and most excipients in a 0.3 mL dose. The modRNA content is listed as either 30 mcg (0.03 mg) for the common 0.3 mL prefilled‑syringe presentation or 10 mcg (0.01 mg) in some single‑dose vial presentations ^{[1] [3]}. The lipid components for the 30 mcg dose are given as approximately 0.43 mg of ((4‑hydroxybutyl)azanediyl)bis(hexane‑6,1‑diyl)bis(2‑hexyldecanoate) (the ionizable lipid), 0.05 mg 2‑(polyethylene glycol 2000)‑N,N‑ditetradecylacetamide (PEG‑lipid), 0.09 mg 1,2‑distearoyl‑sn‑glycero‑3‑phosphocholine (DSPC), and 0.19 mg cholesterol ^{[1] [2]}.

2. Non‑lipid excipients and their masses

The label also specifies buffering/stabilizing ingredients and sugar: for a 0.3 mL 30 mcg dose the formulation contains 0.06 mg tromethamine, 0.4 mg tromethamine hydrochloride, and 31 mg sucrose; the 10 mcg 0.3 mL dose lists proportionally smaller lipid masses (0.14 mg ionizable lipid, 0.02 mg PEG‑lipid, 0.03 mg DSPC, and 0.06 mg cholesterol) but the tromethamine and sucrose figures are the same as in the larger presentation ^{[1] [4]}.

3. Why numbers differ between presentations

Pfizer’s materials and the FDA‑facing labeling identify two dose presentations for the seasonally adapted vaccine: different mRNA amounts are used for different age groups and presentations (10 µg vs. 30 µg). The excipient lipid masses are proportionally smaller with the 10 µg presentation, while some stabilizers like sucrose and tromethamine are listed at the same absolute amounts across those 0.3 mL formulations in the labeling ^{[1] [4]}. That means the excipient composition — and therefore the listed milligram amounts — depends on which specific product vial/syringe you have.

4. Where these numbers come from and how reliable they are

The numeric breakdown above is taken directly from manufacturer and regulatory labeling and corroborated by DailyMed and Pfizer press/medical information pages; those documents are the primary, authoritative sources for per‑dose ingredient masses ^{[1] [2] [4]}. Reporting outlets summarizing FDA approval also restate the 10 µg vs. 30 µg mRNA content for the 2025–2026 formula ^{[3] [5]}. These are the appropriate sources for exact masses; alternative claims should be checked against those labels.

5. What the labels do not say (limitations of available reporting)

Available sources do not mention every possible trace impurity or manufacturing‑level component (for example residual solvents, DNA, or process‑related impurities) in the publicly posted patient and prescribing information; those are governed by regulatory filings and quality‑control data not reproduced verbatim in consumer labeling (not found in current reporting). Also, the labels identify ingredient names and masses but do not provide mole counts, particle counts, or per‑dose molecular ratios beyond what is printed ^{[1] [2]}.

6. Context and competing viewpoints

Pfizer’s public materials emphasize dose, lipid composition and safety data as the basis for FDA approval and distribution ^{[6] [7]}. Independent or critical commentary about vaccines in general exists in other outlets, but the precise ingredient masses are technical facts drawn from the company and regulator documents; any dispute about those figures would need to cite an alternate authoritative filing. If readers are seeking more detailed analytical chemistry (e.g., exact molecular weights, molar ratios or impurity profiles), those data are not presented in the patient‑facing labels cited here ^{[1] [2]}.

7. Practical takeaway for readers

If you need the exact milligram or microgram content for a specific Comirnaty dose, consult the 0.3 mL product labeling or the provider vaccine card/packaging; the label lists 30 µg or 10 µg mRNA and the lipid and excipient masses shown above ^{[1] [4]}. For regulatory or clinical questions about safety, dosing by age group, or batch‑specific details, contact Pfizer Medical Information or review the full prescribing information linked on DailyMed and Pfizer’s medical pages ^{[1] [2]}.