Sodium Benzoate safe?

tasiaashtontasiaashton Member
edited August 2014 in Formulating
Hi! I keep reading comments on different "natural" sites that Sodum Benzoate is toxic and to stay away from cosmetics with this ingredient. I also read that it is toxic only at high levels when ingested or when it is mixed with vitamin C or E or color additives - something about it adding to the ADHD in children and turning into benzene, a known carcinogen. I just had an awesome product made that contains this ingredient as a preservative and now I'm second guessing it...Can anyone clarify this for me? Is it safe in cosmetics? cleaning products? I thought you all would have the most educated answer to this and I want to be able to explain it to my customers correctly. Thank you in advance.  :-)


  • MakingSkincareMakingSkincare Member, Professional formulator
    Unfortunately there is a LOT of scaremongering in this industry so this means it's tricky to decipher which ingredients are considered safe. Cosmetic chemists use which provides unbiased, scientific, expert advice on cosmetic ingredients and, the European Scientific Committee for Consumer Safety is a politically and commercially impartial panel of doctors and toxicologists, whose job it is to review safety data for materials - you can see their reports/opinions on ingredients here
    Jane Barber (free online course)
    Formulation discussion forum (18,000 members):
  • Thank you very much for these links!!

  • Bill_TogeBill_Toge Member, Professional Chemist
    brief summary of the SCCS opinion, 2005 (link to full text):

    the LD50 for dermal toxicity (the dose needed to induce lethal effects in 50% of the test subjects) was found to be greater than 10,000 mg per kg of body weight; they stopped the test at 10,000 mg per kg

    assuming the average person weighs 60 kg, this means the average person would need to directly apply 600+ grams of concentrated benzoic acid/sodium benzoate to their skin before they started showing symptoms of poisoning

    the rate of absorption through the skin was calculated to be 3% per hour, under an air- and water-tight patch; considering benzoic acid/sodium benzoate is typically present at 0.5% or less of a cosmetic products, and that said product is generally left open to the air once it's been applied to the skin, almost none of it would get into the body

    furthermore, there was no evidence of any carcinogenicity, mutagenicity or reproductive toxicity (characteristic symptoms of benzene poisoning) due to benzoic acid/sodium benzoate

    I suspect the panic about it being reduced to benzene comes from J. Agric. Food Chem., 1993, 41 (5), pp 693–695 (link), which describes how benzoic acid can be reduced to benzene by oxygen which has reacted with vitamin C and iron/copper ions; however, mass-produced foods and cosmetics are typically made with deionised water, meaning there is typically next to no iron or copper present in the finished product

    hope this helps!
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • Well it is used to preserve Sprite, Fanta and Pepsi Max (E211) so that's safe enough for me ;)
  • I have both sodium benzoate and potassium sorbate, and have used both to preserve shampoos, but have standardised on sorbate due to the irritation potential of benzoate.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • MakingSkincareMakingSkincare Member, Professional formulator
    I hear you Belassi, sodium benzoate failed patch tests so if we use it it is at a low level.
    Jane Barber (free online course)
    Formulation discussion forum (18,000 members):
  • shapeshifterstudioshapeshifterstudio Member, PCF student
    Thank you, @makingskincare, for the great links, I hadn't seen them before!
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