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Sodium hydroxymethylglycinate

Today's Chemical:

Sodium hydroxymethylglycinate

EWG Skin Deep Hazard Score:


What is it:

Sodium hydroxymethylglycinate is a cosmetic preservative used shampoos, baby wipes, cleaning agents, cleansing bars, lotions and many other household products.  

What are its risks:

  • Sodium hydroxymethylglycinate works as a preservative by slowly releasing formaldehyde.  This can be a problem for a number of reasons.  First, being that formaldehyde is a known carcinogen.  Second, it's a skin irritant and sensitizer.  (Source

Steph's Opinion:

While EWG only gives it a "2" hazard score, I would rate it much higher.  It should be rated the same as other formaldehyde-releasing preservatives like DMDM Hydantoin (7-8) and Diazolidinyl urea (5). 

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Reader Comments (8)

Do you even read (or know how to read) toxcicity reports on all these products? While I agree that some chemicals listed are dangerous. But what you have to know about something like Sodium hydroxymethylglycinate is that yes it is a slow realeasing formaldehyde donor - HOWEVER for it to be a "risk" you would have to drink or bathe in the raw material itself every day for years. Clearly that is not how the product is used or intended to be used!

Fri, September 21, 2012 | Unregistered CommenterKim

Hi Kim! Thanks for your question!

I hear that argument a lot: "You'd need to bathe yourself in it every day for years." But, unfortunately, that's what so many people are doing. With so many products that we use every day: shower gels, shampoos, lotions, sunscreens, perfumes, makeups--if they're all off-gassing formaldehyde, it's an accumulative effect. In toxicology this is called chronic exposure. Of course, a product with Sodium hydroxymethylglycinate (SMHG) isn't going to give you cancer after just a few days of using one product with it, but if you use that product day after day, along with other products containing formaldehyde, it could affect your health. Cancer is a very complicated process that usually can't be pinpointed to one particular exposure or event. It's a balance, an ongoing fight within the body of mutations in cells, of proto-oncogenes (genes that stimulate cell proliferation) and tumor suppressor genes (genes that keep proliferation in check). Pro-oxidants and anti-oxidants. Mutated cells and healthy cells. Some substances, like formaldehyde, proliferate the growth of cancerous cells. Other substances, like antioxidants found in certain fruits, herbs, and vegetables, would slow or stop their growth. We all have the right to choose which ingredients we want to use on our skin, just like we have a choice of which foods we should eat. Some people choose a diet of fast food and processed sugars. Others choose organic fruits and vegetables and lean proteins. Some people are okay with exposing themselves to these low levels of carcinogens. Others prefer to reduce their risk as much as possible and avoid them. As someone who has struggled with hormonal balance my entire post-pubescent life, I know that the estrogen dominance that I battle every day puts me at a higher risk for breast and other reproductive cancers. So, I try to do everything I can to protect myself, and that includes avoiding as many carcinogens and xenoestrogens as I can, even if they're at low levels. My aim with this blog is to educate consumers with information based on the available data so they can make informed choices about these things that can affect their health in very personal ways.

Getting back to SHMG and formaldehyde...there's also the risk of skin irritation, which can show up as an immediate effect. The University of California's Department of Medicine says "Studies on SHMG in animals have demonstrated potential for sensitization and dermatitis, and formaldehyde-allergic patients have been reported to improve when products containing SHMG are avoided. Patients and providers need to be aware of this preservative." So, if people that are allergic to formaldehyde do better when SHMG is avoided, that would tell you that formaldehyde definitely is present with this preservative and in a high enough amount--even when diluted in a product--to cause an immediate and harmful effect on the human body.

I appreciate your question. If you have any safety data counter to this that you'd like to share, I'd be happy to revise or append my article.

Fri, September 21, 2012 | Registered Commenter[Stephanie Greenwood]

Stephanie, great response. Please keep doing what ur doing. If only others had the same passion for "natural" products as you. Instead they argue and stay in denial. In what world ever, is it ok to immerse ourselves in chemicals or natural toxins, or mess with our food by genetically modifying it or even eat foods that have been sprayed with pesticides or fed with hormones and antibiotics! Where did we as society go so wrong? Why mess with nature!!! In reason of course,antibiotics for example have their place. Its ridiculous, and yet we all wonder why we have digestion and gut health problems, why we are suddenly having outbreaks of acne post pubescence, why our cholesterol is sky rocketing, why obesity is an epidemic in today's society... of course there are other contributing factors such as stress, but you get my point. Good on you Steph

Sun, September 30, 2012 | Unregistered CommenterHugo Knight

hello from greece or hello from HELLAS .
I found your shight very interesting and well informed. I am aesthetic (4 years of studies) and i like your job.
anyway iam aesthetic but im not chemist so i want to learn a lot of them.
my todays' question concerns aloe vera. i want to know in what way i could use it in my home made cosmetics.
(Sorry for my english....)

Sat, March 23, 2013 | Registered Commentermaria konsta

Hi Stephanie, I have been researching SHMG and I would like to ask if you know how much formaldehyde is released into the product for a given concentration.

The reason I ask is that I noticed on Wiki that any cosmetic containing more than 0.05% Formaldehyde has to be labelled Warning Contains Formaldehyde!

Thu, July 11, 2013 | Unregistered CommenterFiona

Unfortunately I don't know that answer--it would likely have a number of variables, including the packaging used, exposure to light, and exposure to heat.

Fri, August 30, 2013 | Registered Commenter[Stephanie Greenwood]

My partner and I tried a new lubricant called Carrageenan. Its claim and appeal was that it was an "all natural" product. That there where no glycerin or parabens in the product. After using it on two occasions in the same day, My male partner started to experience a burning sensation which has lasted 10 hours and counting when he urinates. After some research of the contents of the product I discovered that Sodium Hydroxymethylglycinate is a known irritant among other things. My question is has anyone else experienced this problem and what advise can you give me as far as treatment options? Kim

Sat, July 5, 2014 | Unregistered CommenterKim

Many thanks for your thoughtful and complete answers and responses. As I am 79 and have MCS and COPD I appreciate your pointing out the cumulative effects of the sea of toxic chemicals we live in today. Keep up the good work.

Sat, March 31, 2018 | Unregistered CommenterByron Woolcock

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