The Pfizer vaccine has the following ingredients, which are essentially the same as what’s in the Moderna version, but they use a few different salts in their pH control and the lipid formula is slightly different. The explanations under the headings that follow include the percentage that each major ingredient group comprises.

1. mRNA
2. lipids ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate), 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-Distearoyl-sn-glycero-3-phosphocholine, and cholesterol)
3. potassium chloride
4. monobasic potassium phosphate
5. sodium chloride
6. dibasic sodium phosphate dihydrate
7. sucrose

mRNA (≈0.001%)

Right now, in essentially every cell in your body, the DNA within the cell nucleus is sending out an mRNA message to the cytoplasm. A ribosome is about to start working on following the instructions therein, and other molecular machines will continue the work to produce a protein or whatever. But I oversimplify. The only differences between that process and the vaccine is that your cells will never code for the spike protein, and the cheat sheet that your immune system needs (but will never get from the cell) is coming from the other side of the cell. mRNA always goes to the cytoplasm, never to the nucleus, and thus has no way of “changing your DNA” as some antivaxxers proclaim. It is physically impossible for mRNA to change your DNA.

Lipids (≈10%)

Lipids are fats. All of your cells membranes are phospholipids. Much of what is listed in the lipids section of the ingredient list is decipherable only by well trained scientists with significant training in chemistry. One simplification is that these are standard nomenclature for the structure of many natural things. For example, phosphocholine (see 3rd component of lipid above) is a molecule found in lecithin, which is a nutritional supplement. Lecithin is in your tissues, egg yolk, and plants. Fancy scientific words include proton, hydrogen, phosphate, etc., but protons are in everything, hydrogen is in water, and phosphates are in your food and soaps. Don’t be alarmed by technical jargon. However, two of the four lipid ingredients are easy to understand — cholesterol and PEG-2000. Your liver makes 80% of the cholesterol in your body that is used as building blocks in hormones and cell membranes. The rest of your cholesterol comes from food. PEG-3350 is the main ingredient in laxatives like Miralax, which is a bottle of pure joy known well to anyone who has endured a colonoscopy. A less potent version of that ingredient (PEG-2000) is in the vaccine. The number associated with PEG is related to its molecular weight. 

Salts (≈7%)

All of the salts (minerals) in the vaccine are there to balance your body’s pH. Period. That’s all they do.

Potassium Chloride is prescribed to patients will low potassium levels because their heart is likely to fail if potassium levels get too low. Ever heard of the sodium-potassium pump? The exchange of sodium and potassium ions across cell membranes is what causes muscle action. As a drug, it is classified under minerals and electrolytes. You need them to live. It is an electrolyte that has the same electrolyte profile as your blood.

Monobasic Potassium Phosphate is another drug prescribed to patients with certain needs. Its main function is to prevent calcium kidney stones from forming by interacting with calcium in a way that brings balance within the body. It is a pharmaceutical buffering agent and an electrolyte replenisher, among other things. Main point here is that it is not new to medicine and it is basic (pun intended). Keeps the vaccine at a natural pH that is neither acidic or basic.

Sodium Chloride is table salt. You might have heard of it before today. It is an electrolyte that has the same electrolyte profile as your blood.

Dibasic Sodium Phosphate Dihydrate. This one’s more complicated, but one of its uses is for making starch. It’s an emulsifier in foods and even shows up in detergents. But when it comes down to it, it’s sodium and phosphorus, which are things you eat on a daily basis in foods like milk, cheese, nuts, and colas. Keeps the vaccine at a natural pH that is neither acidic or basic.

Sugar (≈83%)

Sucrose is produced naturally in plants and is nothing less than one molecule of glucose joined to one molecule of fructose. It has a chemical formula involving carbon, hydrogen, and oxygen (C₁₂H₂₂O₁₁).

What Purpose Do These Ingredients Serve?

The sugar keeps the lipids from fracturing under the low temperature required for storage and transport. The lipids (like all the others in your body right now) carry the mRNA to the cell membrane for transfer. The salts balance the body’s pH. The mRNA is the cheat sheet on COVID that your cells will never produce on their own.

How Much Stuff Is In The Shot?

From Maintaining Safety with SARS-CoV-2 Vaccines | NEJM

NOTE: “mg” refers to milligrams, or 1/1000 of a gram.

• 0.43 mg ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate), 
• 0.05 mg 2[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 
• 0.09 mg 1,2-distearoyl-sn-glycero-3-phosphocholine, and 
• 0.2 mg cholesterol, 
• 0.01 mg potassium chloride, 
• 0.01 mg monobasic potassium phosphate, 
• 0.36 mg sodium chloride, 
• 0.07 mg dibasic sodium phosphate dihydrate, and
• 6 mg sucrose. 

The diluent (0.9% sodium chloride Injection) contributes an additional 2.16 mg sodium chloride per dose. When you consider that in the percentages, you end up with 27% sodium chloride and 64% sucrose, or 91% of your immunization is the same salt and sugar that’s in your kitchen right now.

Conclusion

With the exception of the vanishingly FEW people on the planet who have an illness or pre-existing medical condition that precludes vaccines, or are presently in cancer treatments, etc., we should all get the vaccine without fear. The ingredients used in these vaccines are not the problem that antivaxxers make them. The vaccines are well tested and the new mRNA technology has been under development for 30 years.

PEG is the most likely culprit for adverse reactions in this vaccine, but we knew that BEFORE the vaccines were developed. This February 2021 study reveals that a simple allergy test could alert the vaccine recipient to their potential risk. Though there have been thousands of adverse reactions during the vaccine rollout, most were mild, some were severe, none of them resulted in death. We are alarmed because the 0.01% is happening all at once in a population of millions. These vaccines are still safer than most drugs you buy over the counter.