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Chemical Formula


The Cosmetic Ingredient Review Expert Panel was confident in March that an expanded group of 20 parabens would come out of its re-review with a safe-as-used determination, despite the insufficient data conclusion it posted at the time.

The panel is expected to revisit the subject and issue a tentative amended report Sept. 24-25 in Washington. It remains to be seen if data gaps have been filled to the panel’s satisfaction and if the newly available information in any way shakes the group’s convictions.

Developmental and reproductive toxicity continues to be the foremost health concern when it comes to preserving cosmetics with parabens, and the ingredients’ use is as much a hot-button issue today as in years past.

In June 2017 when CIR’s experts agreed to reopen the book on parabens and add 4-hydroxybenzoic acid to the group, Donald Belsito, Leonard C. Harber Professor of Dermatology at Columbia University Medical Center, urged his fellow panelists to approach the task cautiously.

“I think for many reasons, we need to be very, very careful with this document,” he said. “There are a huge number of NGOs, [consumers] and manufacturers who are very concerned about the safety of parabens, and I think that we need to be very grounded in our decision and be able to justify it very, very clearly.”

At the same time, personal-care formulators’ preservative palette is shrinking, raising concerns about microbiological safety that have both industry and regulators working to impress on the public the importance of having adequately preserved cosmetics. (Also see "ICCR Publishes Cosmetic Preservatives FAQ To Raise Public Awareness" - Rose Sheet, 16 Jan, 2016.)

“We need effective preservatives,” noted CIR panelist Thomas Slaga, a pharmacology professor at the University of Texas Health Science Center in San Antonio, at the March meeting. “I’m definitely not anxious to see any disappear at the moment from what we’ve got left. But on the other hand, we have things that we need to be careful about.”


“If the [revised] lower MOS is still considered protective, it would not necessitate a more restrictive use recommendation. If the lower MOS is not considered protective, then a lower exposure dose is a likely recommendation.” – CIR Executive Director Bart Heldreth


Over the past six months, CIR staff have compiled an updated dossier for the panel’s consideration, which includes additional input on European regulations that in recent years have banned various parabens and restricted others – namely methylparaben, ethylparaben, propylparaben and butylparaben – when used by cosmetic formulators independently or in mixtures.

Belsito, who heads up one of the CIR Expert Panel’s two teams, expressed reservations during the last meeting about pronouncing parabens safe at current use levels – which in the US are known to exceed EU limits – without addressing the EU’s divergent position. (Also see "CIR Panel's Parabens Review Leaning Toward Safe, But 'Insufficient Data' For Now" - Rose Sheet, 12 Mar, 2018.)

“I think our conclusion would differ significantly from the conclusion that’s been issued in the EU, and we need to capture that data, we need to look at it and we need to decide – Do we agree with them or do we disagree with them? – and either way put that into our discussion,” he said.

From Belsito’s point of view, “in the end it comes down to what we're going to do with these margin of exposures based upon the new data we have and how we're going to handle that.”

Enter P&G Scientist

The CIR panel’s 2008 assessment of parabens that determined them safe as used, a finding the group reaffirmed in 2012, assumed dermal absorption of 50%, a far more conservative estimate compared with the 3.7% absorption rate used by the EU’s Scientific Committee on Consumer Safety when it decided that paraben concentrations in cosmetics needed to be reined in. (Also see "CIR To Consider Re-Review Of Parabens Following Europe’s New Guidance" - Rose Sheet, 5 Mar, 2012.)

The key difference was that the European committee based its stance on a much lower no-observed-effect level (NOEL) – 2 milligrams per kilogram of body weight per day – versus the no-observed-adverse-effect level (NOAEL) of 1,000 mg/kg bw/day that factored in the CIR panel’s margin of safety (MOS) calculations and ultimately its 2008 safe-as-used conclusion.

For adults, CIR’s NOAEL yielded a MOS of 1,690 for single-paraben products and 840 for multiple-paraben products. Paraben MOSs for infants were even higher – around 6,000 and 3,000, respectively.

MOS expresses the ratio of a NOAEL obtained from animal toxicological studies to estimated systemic exposure dose in humans. According to, a site run out of the UK by chemical regulatory experts, a MOS greater than or equal to 100 is generally considered to be protective.

Consumer watchdog groups often have their own ideas about acceptable MOSs. The Environmental Working Group, for example, is more comfortable with MOSs in the thousands.

In March, CIR panelists heard from George Daston, a Victor Mills Society Research Fellow at Procter & Gamble Co., after requesting outside expertise to gain perspective on new DART research showing adverse effects in rodents when they were administered butylparaben in oral doses as low as 10 mg/kg/day.

Daston ended up recommending a NOAEL of 160 mg/kg/day to calculate a conservative MOS for butylparaben, “which could then be inferred to other members of the parabens group,” he said.

CIR took his advice. In its report prepared for the upcoming meeting, the group sets out recalculated MOSs based on the 160 mg/kg/day NOAEL. The MOSs for adults are 270 and 135 for single- and multiple-paraben use, and for infants, 952 and 476, respectively.

The organization’s math again used a 50% dermal penetration estimate. In its report, CIR notes that updated MOSs using SCCS’s 3.7% estimate would increase those MOSs more than 10-fold.

CIR’s report draws no conclusions from the revised data, leaving that responsibility to its Expert Panel.

Asked whether the markedly lower MOSs are likely to change the panel’s position on parabens’ safety, CIR Executive Director Bart Heldreth refrained from speculating.

“If the lower MOS is still considered protective, then no, it would not necessitate a more restrictive use recommendation,” he said in an email. “If the lower MOS is not considered protective, then a lower exposure dose is a likely recommendation.”

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