Propylene glycol is metabolized in the human body into Pyruvic acid, which is a normal part of the glucose metabolism process and is readily converted to energy.
The oral toxicity of propylene glycol is very low, and large quantities are required to cause perceptible health damage in humans. Serious toxicity will occur only at plasma concentrations over 4g/L, which requires extremely high intake over a relatively short period of time. It would be nearly impossible to reach toxic levels by consuming foods or supplements, which contain at most 1g/kg of PG. Cases of propylene glycol poisoning are related to either inappropriate intravenous use or accidental ingestion of large quantities by children.
The potential for long-term toxicity is also low. In one study, rats were provided with feed containing as much as 5% PG over a period of 104 weeks and they showed no apparent ill effects. Because of its low chronic oral toxicity, propylene glycol was classified by the U. S. Food and Drug Association "generally recognized as safe" (GRAS) for use as a direct food additive.


-Sursa Wikipedia


Asta ar trebui sa va mai lamureasca. Mai incolo o sa incerc si sa traduc, sa vad daca am timp. In principiu, in acest articol scrie ca pentru a constitui un pericol serios pentru sanatate, trebuie sa fie ingerata in organism o cantitate foarte mare de PG, in concentratie de 4g\L in plasma din sange. A atinge cote toxice de PG in organism este aproape imposibil de realizat prin consumul alimentelor sau suplimentelor in care se adauga de obicei PG (presupun ca din aceasta categorie face parte si e lichidul )


PS. daca cineva observa o greseala in informatiile acestea, il rog sa ma corecteze, eu doar am luat informatii de pe Wikipedia si am tradus partea esentiala, nu sunt chimist, nici pe aproape.