Ingredient Deep Dive

What's Actually In The Vial?

Toxicology Explorer
Select an ingredient to explore its known toxicity profile, industrial uses, and biological mechanisms.

IARC Classification: Group 1 Carcinogen

Classified as "Carcinogenic to humans" by the International Agency for Research on Cancer.

Biological Mechanism

Formaldehyde is a potent protein cross-linker. It "fixes" tissues by bonding proteins together, which is why it is used in embalming. In the body, this cross-linking can damage DNA and disrupt cellular function.

In Vaccines

Used to "inactivate" viruses (Polio, Hep A, Flu). Residual amounts remain in the final product.

Known Risks

  • Nasopharyngeal Cancer: Strong causal association.
  • Leukemia: Associated with myeloid leukemia.
  • DNA Damage: Causes DNA-protein crosslinks.
SV40 (Simian Virus 40)

Contaminant

Safety Concerns

A DNA virus found in monkey kidney cells used to culture polio vaccines. Known to cause cancer in animals. Millions of Americans were exposed to SV40-contaminated polio vaccines between 1955 and 1963. DNA fragments of SV40 have been found in human tumors.

Found In:

Polio Vaccines (Historical)Potential contaminant in modern vaccines using monkey kidney cells
Aluminum

Adjuvant (stimulates immune response)

Safety Concerns

Neurotoxin. Accumulates in the brain and bones. Linked to autoimmune issues, macrophage myofasciitis, and neurological disorders. The amount in the childhood schedule exceeds FDA safety limits for parenteral nutrition.

Found In:

DTaPHepBHibHPVPneumococcal
Formaldehyde

Inactivator (kills viruses/bacteria)

Safety Concerns

Known carcinogen. Linked to leukemia and brain cancer. Neurotoxic. While naturally occurring in the body, injection bypasses natural filtration systems.

Found In:

PolioDTaPInfluenzaHepA
Polysorbate 80

Emulsifier (keeps ingredients mixed)

Safety Concerns

Increases blood-brain barrier permeability, potentially allowing other toxins (like aluminum) to enter the brain. Linked to infertility and ovarian damage in animal studies.

Found In:

DTaPInfluenzaHPVRotavirus
Thimerosal (Mercury)

Preservative

Safety Concerns

Potent neurotoxin. While removed from most single-dose childhood vaccines, it remains in multi-dose flu vials and some international vaccines. Linked to neurological damage and developmental delays.

Found In:

Influenza (Multi-dose vials)
Fetal Bovine Serum

Growth Medium

Safety Concerns

Risk of contamination with animal viruses (like SV40). Ethical concerns regarding sourcing from unborn calves.

Found In:

MMRRotavirusVaricella
Human Fetal Tissue (MRC-5, WI-38)

Growth Medium

Safety Concerns

Derived from aborted human fetuses. Ethical and religious objections. Potential for residual human DNA integration and autoimmunity.

Found In:

RubellaVaricellaHepARabies
Monosodium Glutamate (MSG)

Stabilizer

Safety Concerns

Excitotoxin. Can overstimulate neurons to the point of cell death. Linked to migraines and neurological issues in sensitive individuals.

Found In:

InfluenzaMMRVaricellaZoster
2-Phenoxyethanol

Preservative

Safety Concerns

Toxic to the liver and kidneys. Can depress the central nervous system and may cause vomiting and diarrhea.

Found In:

IPVDTaPHepAHepBHib
Antibiotics (Neomycin, Streptomycin, Polymyxin B)

Prevent bacterial growth

Safety Concerns

Risk of severe allergic reactions (anaphylaxis) in sensitive individuals. Disruption of gut microbiome.

Found In:

MMRPolioVaricellaInfluenza