07/07/2026
There are two types of vitamin K injections used in the US. Let’s examine the ingredients in these vitamin K injections.
Both contain phytonadione (vitamin K1) but different inactive ingredients. The most common type used is a preservative-free version which contains
· Propylene glycol: acts as a solvent to keep the fat-soluble vitamin K in solution. Propylene glycol is commonly found in foods, supplements and other medications. The evidence indicates that it is safe to consume up to 25 mg/kg/day of propylene glycol. Vitamin K injection contains 10.4 mg of propylene glycol, or roughly 3.3 mg/kg for 7 lbs.
· Polysorbate 80: a plant-based sugar alcohol (sorbitol) and a fatty acid (oleic acid) is an emulsifier that also assists with keeping vitamin K in solution. Although parents may cite information from the package insert that reveals an incident where it was felt to be the cause of toxicity in premature babies receiving IV vitamin E, these babies received > 70 mg/kg daily over several weeks. A very high dose compared to the 10 mg of polysorbate 80 (approximately 3 mg/kg for 7 lbs) found in the one-time vitamin K injection.
· Sodium acetate anhydrous (0.17 mg) assists in maintaining a neutral pH. Although this ingredient contains about 0.05 mcg of aluminum, there are no toxicity concerns with this small amount.
· Glacial acetic acid (.002 ml) is a weak acid that is used to adjust the pH and has no safety concerns. It is the main component of vinegar.
The second type of vitamin K shot contains a preservative. The evidence on this vitamin K injection indicates that it is also a safe newborn medication. This vitamin K formulation contains
· Benzyl alcohol is a preservative that prevents bacterial growth. The safe daily intake of benzyl alcohol set by the WHO is 5 mg/kg. The injection contains 4.5 mg or roughly 1.4 mg/kg for 7 lbs. The drug insert warns that benzyl alcohol can cause toxicity, however, this necessitates much higher, daily, intravenous dosages (> 99 mg/kg/day) and historically occurred in preterm infants with the use of IV flushes that contained the preservative. This practice is no longer recommended.
· Polyethoxylated castor oil: This is a fatty acid that acts as an emulsifier and solvent, keeping vitamin K in solution. There have been rare reports of an anaphylactic reaction among patients receiving large intravenous doses, but none among newborns.
· Dextrose monohydrate: glucose – no safety concerns here 😉
Some important points to consider include
· A vitamin K injection is highly effective at preventing vitamin K deficiency bleeding (VKDB), essentially preventing all late VKDB which frequently occurs in the brain.
· It is not possible to determine infants at risk for VKDB based on risk factors.
· The greatest risks associated with VKDB are exclusively breastfed infants and those who don’t receive the vitamin K injection at birth
· Today’s available vitamin K injections have been found to be very safe with minimal side effects that may include pain, bleeding, and bruising at the injection site.
You will find additional information on these two websites, which are also written for the lay public and are good references for expectant parents.
https://evidencebasedbirth.com/evidence-for-the-vitamin-k-shot-in-newborns/ (Links to an external site.)
https://scienceofmom.com/2015/11/09/are-the-ingredients-in-the-newborn-vitamin-k-shot-safe/ (Links to an external site.)
