This is part of our ongoing series helping consumers better understand chemicals, chemistry, and product formulations. We translate the science, bust the myths, and give you an honest assessment, so you can make informed choices for your family!
Ingredient: Silver Dihydrogen Citrate (SDC)
What it is: Ionic silver in a citric acid solution.
What it does: Fights bacteria. Most personal care products are made with a lot of water and a variety of nutrients (consider all of the natural oils and botanicals in Honest products!) which make an incredibly hospitable breeding ground for microorganisms. What’s worse – the product might smell and look just fine, but be swarming with bacteria or fungi that are dangerous to your health. Effective preservatives are vital for ensuring safety!
Why we use it: Preservatives are especially difficult to formulate because they have to be strong enough to kill bacteria, but they also can’t impact the effectiveness of other ingredients. Of course, for The Honest Company, safety is key. Most conventional preservatives are linked to things like hormone disruption and even cancer. We were thrilled to discover SDC which is non-toxic, non-irritating, colorless, and odorless. In fact, based on the U.S. Environmental Protection Agency (EPA) toxicity categorization of antimicrobial products that ranges from Category I (high toxicity) down to Category IV, SDC is rated in the lowest toxicity category (comparable to tap water), while conventional preservatives typically fall into Categories I and II.
Another awesome feature of SDC is that it doesn’t appear capable of promoting antibacterial-resistant strains of microbes (a disturbing side-effect of many preservatives). According to Professor Simon Silver of the Department of Microbiology & Immunology at the University of Illinois, “while bacteria have the genetic ability to develop a resistance to silver, they almost never do.” In an interview with Forbes, Silver says that in “30 years of research, he has heard of it happening only twice. And as soon as the resistance develops, it quickly disappears because the kind of change required to protect against silver weakens the microbe dramatically.”
Why we’re featuring it today: Simply put, we get a lot of questions about SDC – particularly about its toxicity and whether or not it’s made with nanoparticles. We want to put your minds at rest on this one, so here are some additional details about SDC.
In regards to toxicity, hopefully the information above about its EPA categorization helps demonstrate how safe this ingredient is, but here’s a little more evidence just to emphasize the point:
Silver is not on California’s Prop 65 list of carcinogens, reproductive toxins, or developmental toxins and there are no data indicating that silver causes developmental toxicity.
Silver compounds are not skin or eye irritants or sensitizers and are not classified as “asthmagens” (respiratory sensitizers) by the Association of Occupational and Environmental Clinics or other sources.
In a scientific review conducted by the EU’s Scientific Committee on Consumer Products, they deemed SDC to be non-toxic by oral exposure, non-toxic by dermal exposure, non-irritating, and that it’s not a skin sensitizer. (Though, they do call for additional testing for long-term impacts given the increased use of this ingredient.)
The World Health Organization assessed the safety of using silver compounds for sanitizing drinking water and concluded that there have been no reports of toxic effects resulting from the exposure of healthy persons to silver.
In regards to SDC using nanoparticles, this simply isn’t the case. SDC uses ionic silver whereas silver nanoparticles are metallic silver. What’s the difference? Well, ionic silver is single atoms of silver that have lost an electron leaving them with a net positive charge. Metallic silver nanoparticles (aka “Nano Silver”) consist of many silver atoms (that have their electrons in tact) clustered together to form a particle 1-100 nanometers in size.
You’re probably thinking “what the huh?” We understand. It took us quite some time to understand it all, too. Without going into a full chemistry lesson, just let it be known they’re very different – in size AND in how they behave.
Fundamentally, ionic silver’s positive charge makes it naturally attract pathogens (which are almost all negatively charged) and then the ions absorb oxygen, which kills the bacteria by interfering with their respiration. This antimicrobial property, along with its non-toxicity, has given silver an essential role in medicine for thousands of years. And while for most of that time people didn’t understand why silver was so effective. We now know it’s the power of the ions!
Any other questions about SDC? Let us know in the comments and we’ll do our best to answer them!
Here at the Honest offices, we get pretty geeky about our product formulations. Most people cringe at the idea of spending hours and hours poring over scientific studies, but we find it fascinating. And that’s how we end up creating products that are not only safe, but also super effective, too. We keep the nasty stuff out and find the best stuff to put in.
We spend a lot of time thinking about every ingredient that we include in our formulas, and wanted to share some of the exciting things we’ve learned about lavender (which is currently used in our Lip Balm and brand new Healing Balm). It’s a delicate little flower with some amazing super powers!
Here’s a little about what we’ve learned…
Lavender essential oils have been used both cosmetically and therapeutically for centuries and are considered to be some of the mildest of known plant essential oils. Since it’s been used for so long, there’s oodles of anecdotal evidence, but what do the scientific studies say? Although some of the data is still inconclusive, there does seem to be both scientific and clinical evidence revealing some pretty exciting stuff:
During our research, we also found various Web sites expressing concern over the use of lavender – primarily because of estrogenic properties and cases of contact dermatitis. So, we looked into that, too – and here’s what we found:
In 2007, several doctors released a brief report linking tea tree and lavender oil to male prepubertal gynecomastia (breast growth) because three boys who were using products containing these ingredients were diagnosed with the condition. Since then, the report has been mentioned widely online and has caused much confusion and, we’d say, unnecessary worry.
There were many flaws in this report including:
What about other testing for estrogenic impacts? Well, there was a follow-up test that indicated a hormonal effect, but it was in vitro (test tube) testing which simply doesn’t translate to actual human exposure. (Also, it should be noted that over 4,000 components of plants have shown some degree of hormonal effect – that’s just the chemistry of nature and life!) Another follow-up study testing lavender oil as it might impact humans in real life exposures (using the model regarded as the “gold-standard in vivo test for estrogenic activity”) showed NO evidence of estrogenic activity.
And, what about contact dermatitis?
Well, skin allergies to lavender oil can happen, but it appears quite rare – and might possibly be due to oxidization (which happens when the oil is stored improperly). Considering that lavender is one of the most widely used essential oils and the cases of reported allergic reactions are so few and far between, we really don’t feel it should be considered an irritant. (Though, please consult your family doctor if you’re still concerned about it.)
All in all, the long list (and evidence) of benefits far outweighs the concerns of risk – and we’re excited to include it in some of our newest formulations!
References
Bickers D, Calow P, Greim H et al 2003b A toxicologic and dermatologic assessment of linalool and related esters when used as fragrance ingredients. Food & Chemical Toxicology 41:919-942
Cassella S, Cassella JP, Smith I 2002 Synergistic antifungal activity of tea tree (Melaleuca alternifolia) and lavender (Lavandula angustifolia) essential oils against dermatophyte infection. The International Journal of Aromatherapy 12(1):2-15
Cavanagh H, Wilkinson J 2002 Biological activities of lavender essential oil. Phytotherapy Research 16(4):301–308
Cherng J-M, Shieh D-E, Chiang W 2007 Chemopreventive effects of minor dietary constituents in common foods on human cancer cells. Bioscience, Biotechnology & Biochemistry 71:1500-1504
D’Auria FD, Tecca M, Strippoli V et al 2005 Antifungal activity of Lavandula angustifolia essential oil against Candida albicans yeast and mycelial form. Medical Mycology 43:391-396
Edwards-Jones V, Buck R, Shawcross SG et al 2004 The effect of essential oils on methicillin-resistant Staphylococcus aureus using a dressing model. Burns 30:772-777
Gattefossé RM 1993 Gattefossé’s aromatherapy. CW Daniel, Saffron Walden
Ghelardini C, Galeotti N, Salvatore G et al 1999 Local anaesthetic activity of the essential oil of Lavandula angustifolia. Planta Medica 65:700-703
Goiriz R, Delgado-Jimenez Y, Sanchez-Perez J et al 2007 Photoallergic contact dermatitis from lavender oil in topical ketoprofen. Contact Dermatitis 57:381-382
Gould MN, Malzman TH, Tanner MA et al 1987 Anticarcinogenic effects of terpenoids in orange peel oil. Proceedings of the 78th Annual Meeting of the American Association for Cancer Research 28:153
Guba R 1998/1999 Wound healing: a pilot study using an essential oil-based cream to heal dermal wounds and ulcers. The International Journal of Aromatherapy 9(2):67-74
Hartman D, Coetzee JC 2002 Two US practitioners’ experience of using essential oils for wound care. Journal of Wound Care 11(8):317-320
Henley D et al 2007 Prepubertal gynecomastia linked to lavender and tea tree oil. New England Journal of Medicine 356: 479-485
Herz R 2009 Aromatherapy Facts and Fictions: A Scientific Analysis of Olfactory Effects on Mood, Physiology and Behavior International Journal of Neuroscience 119(2): 263-290
IFRA 2009 Standards, including amendments as of October 14th 2009. International Fragrance Association, Brussels. http://www.ifraorg.org
Kerr J 2002 The use of essential oils in wound healing. The International Journal of Aromatherapy 12(4):202-206
Kim HM, Cho SH 1999 Lavender oil inhibits immediate-type allergic reaction in mice and rats. Journal of Pharmacy & Pharmacology 51:221-226
Kunicka-Styczyńska A, Sikora M, Kalemba D 2009 Antimicrobial activity of lavender, tea tree and lemon oils in cosmetic preservative systems. Journal of Applied Microbiology 107:1903-1911
Kunicka-Styczyńska A, Sikora M, Kalemba D 2011 Lavender, tea tree and lemon oils as antimicrobials in washing liquids and soft body balms. International Journal of Cosmetic Science 33:53-61
Lis-Balchin M (Ed.) 2002 Lavender: The Genus Lavandula. Taylor & Francis, Inc.
Meneghini CL, Rantuccio F, Lomuto M 1971 Additives, vehicles and active drugs of topical medicaments as causes of delayed-type allergic dermatitis. Dermatologica 143:137-147
Opdyke DL J 1976 Monographs on fragrance raw materials. Food & Cosmetics Toxicology 14 supplement
Politano V et al 2013 Uterotrophic assay of percutaneous lavender oil in immature female rats. International Journal of Toxicology 32(2):123-129
Prashar A, Locke IC, Evans CS 2004 Cytotoxicity of lavender oil and its major components to human skin cells. Cell Proliferation 37:221-229
Sakurada T, Kuwahata H, Katsuyama S et al 2009 Intraplantar injection of bergamot essential oil into the mouse hindpaw: effects on capsaicin-induced nociceptive behaviors. International Review of Neurobiology 85:237-248
Sakurai H, Yasui H, Yamada Y et al 2005 Detection of reactive oxygen species in the skin of live mice and rats exposed to UVA light: a research review on chemiluminescence and trials for UVA protection. Photochemical & Photobiological Sciences 4:715-720
Sibel R et al 2009 The antimicrobial activity of high-necrodane and other lavender oils on methicillin-sensitive and -resistant staphylococcus aureus (MSSA and MRSA). The Journal of Alternative and Complementary Medicine 15(3): 275-279
Soković M, Glamočlija J, Marin PD et al 2010 Antibacterial effects of the essential oils of commonly consumed medicinal herbs using an in vitro model. Molecules 15:7532-7546
Vakilian K, Atarha M, Bekhradi R et al 2011 Healing advantages of lavender essential oil during episiotomy recovery: a clinical trial. Complementary Therapies in Clinical Practice 17:50-53
Yang SA, Jeon SK, Lee EJ et al 2010 Comparative study of the chemical composition and antioxidant activity of six essential oils and their components. Natural Product research 24:140-151
Zu Y, Yu H, Liang L et al 2010 Activities of ten essential oils towards Propionibacterium acnes and PC-3, A-549 and MCF-7 cancer cells. Molecules 15:3200-3210
This is part of our ongoing series helping consumers better understand chemicals, chemistry, and product formulations. We translate the science, bust the myths, and give you an honest assessment, so you can make informed choices for your family!
Ingredient: Potassium Sorbate
What it is: Potassium sorbate is a salt of sorbic acid which is naturally found in some fruits (like the berries of mountain ash). The commercial ingredient is synthetically produced creating what is termed a “nature identical” chemical (chemically equivalent to the molecule found in nature).
What it does: Fights bacteria. Most personal care products are made with a lot of water and a variety of nutrients (consider all of the natural oils and botanicals in Honest products!) which makes an incredibly hospitable breeding ground for microorganisms. What’s worse – the product might smell and look just fine, but be swarming with bacteria or fungi that are dangerous to your health. Effective preservatives are vital for ensuring safety!
Why we use it: Potassium sorbate is a food-grade preservative that has been effectively used for decades and is generally regarded as safe (GRAS) worldwide to preserve food products. It’s easily metabolized by the human body and doesn’t accumulate in either the body or the environment. In fact, the toxicity of potassium sorbate is comparable to that of table salt!
What’s more, it’s included in the Handbook of Green Chemicals and is also Whole Foods Premium Body Care approved. And their standards, developed by a team of scientists over the course of years, are some of the strictest available. If these two credible sources give it a thumbs-up, we do too.
Why we’re featuring it today: Some sites express concern that potassium sorbate might be carcinogenic, neurotoxic, or an endocrine disruptor. However, many studies have been conducted on potassium sorbate (it’s one of the most extensively studied preservatives) and, according to an exhaustive review published in the International Journal of Toxicology, the findings reveal:
Potassium sorbate, at concentrations up to 10%, is practically non-irritating to the eye and only slightly irritating to skin.
Potassium sorbate has been tested for mutagenic effects using bacterial tests, genetic recombination tests, reversion assays, tests for chromosomal aberrations, sister chromatid exchanges, and gene mutations. The weight of evidence indicates that it is not mutagenic.
Potassium sorbate at 0.1% in the diet or 0.3% in drinking water for up to 100 weeks was not carcinogenic.
No developmental effects have been observed.
Formulations containing up to 0.5% were not significant primary or cumulative irritants and not sensitizers.
Currently, the only legitimate health concern with this ingredient is a rare allergic reaction or sensitivity (that could lead to migraines or diarrhea). But even that type of reaction can vary from formulation to formulation, so some products might cause irritation, while others don’t. For this reason, we always caution parents to watch for adverse reactions when using any new product.
We stand behind the safety of our products, but we’re still vigilant about new studies demonstrating risks. Science is always progressing and our understanding of the complicated world of toxicology is always expanding. Should any real risks become apparent, we’d be quick to reformulate (that’s just how we roll)!
Have any other questions or concerns about potassium sorbate? We’re happy to hear them and help you better understand this ingredient!
Reference:
We recently received an inquiry asking us why we say our sunscreen is baby-safe when sunscreen isn’t recommended for babies under 6 months old. It’s a good question! And, with skin cancer on the rise, we felt it was important to help all parents in our community better understand infant sun safety.
Why babies are more vulnerable
Infants are at higher risk of UV damage and skin cancer because their skin is thinner and has lower melanin concentrations than an adult’s skin. According to the article UV protection and sunscreens: What to tell patients, what this means is that “UV penetrates more deeply into skin that is less able to absorb UV radiation.” The doctors who authored the article go on to say, “Animal studies suggest that the skin of children, especially infants, is immunologically immature and less able to respond to UV damage than adult skin. Therefore, extra care must be taken to protect children from UV exposure.”
The latest skin safety recommendations
Previously, the “extra care” recommendation was to keep babies under 6 months of age out of direct sun and covered by protective clothing. Sunscreen was not recommended at all for babies this young. But in the past few years, the American Academy of Pediatrics (AAP) has modified that recommendation. Now they say:
For babies younger than 6 months. Use sunscreen on small areas of the body, such as the face and the backs of the hands, if protective clothing and shade are not available.
Keeping babies out of the sun is still the safest way to protect their delicate, vulnerable skin from the harmful rays of the sun. That’s a fact. But public health officials now recognize that’s not always a possibility and that the safety of shade is relative to the situation. Consider this, even sitting in the shade of an umbrella at the beach cannot entirely protect you from UV rays. According to the U.S. Environmental Protection Agency, “Surfaces like snow, sand, pavement, and water reflect much of the UV radiation that reaches them. Because of this reflection, UV intensity can be deceptively high even in shaded areas.”
At those times, protective clothing can help close the gap and increase skin protection. But there’s inevitably still a little bit of skin exposed (e.g., face, hands, ears)—and that’s when a little bit of sunscreen might be necessary. When that’s the case, the consensus is generally that a broad-spectrum sunscreen made from physical barriers such as zinc oxide and titanium dioxide are the most effective and safest for baby’s sensitive skin.
Why physical barriers are better
In sun protection, there are two categories of active ingredients: chemical absorbers and physical barriers. Chemical absorbers, such as oxybenzone or octocrylene, work by absorbing UV radiation before it affects or damages the skin. However, these ingredients are increasingly being linked to negative health impacts. (For example, oxybenzone — also known as benzophenone - was recently added to California’s Prop 65 list as known to cause cancer and octocrylene is a “strong allergen linked to contact dermatitis in children.”)
The second category of active ingredients in sun protection is physical blockers, such as zinc oxide or titanium dioxide. When the sun hits these blockers it is reflected and bounces away from the skin (versus getting absorbed). These ingredients (unless they’ve been nano-sized – which ours have not been) are natural, generally not absorbed by the skin, and are far gentler on both our skin and the environment.
Honest Sunscreen does not contain chemical absorbers like oxybenzone or octocrylene. It contains only 1 active sunblock ingredient: zinc oxide.
Additional sun safety tips for infants
The FDA recommends keeping the following in mind this summer when outside with infants:
Keep your baby in the shade as much as possible. If you do use a small amount of sunscreen on your baby, don’t assume the child is well protected.
Make sure your child wears clothing that covers and protects sensitive skin. Use common sense; if you hold the fabric against your hand and it’s so sheer that you can see through it, it probably doesn’t offer enough protection.
Make sure your baby wears a hat that provides sufficient shade at all times.
Watch your baby carefully to make sure he or she doesn’t show warning signs of sunburn or dehydration. These include fussiness, redness, and excessive crying.
Hydrate! Give your baby formula, breast milk, or a small amount of water between feedings if you’re out in the sun for more than a few minutes. Don’t forget to use a cooler to store the liquids.
Take note of how much your baby is urinating. If it’s less than usual, it may be a sign of dehydration, and that more fluids are needed until the flow is back to normal.
If you do notice your baby is becoming sunburned, get out of the sun right away and apply cold compresses to the affected areas.
NOTE: Please consult your family health provider with any concerns about sun safety and using sunscreens on your children. The information in this blog post should not replace professional medical advice.
This is part of our ongoing series helping consumers better understand chemicals, chemistry, and product formulations. We translate the science, bust the myths, and give you an honest assessment, so you can make informed choices for your family!
Ingredient: Phenoxyethanol
What it is: Phenoxyethanol can be found naturally in green tea, but the commercial ingredient is synthetically produced in a laboratory creating what’s termed a “nature identical” chemical. Specifically, it’s created by treating phenol with ethylene oxide in an alkaline medium which all reacts to form a pH-balanced ingredient.
What it does: Fights bacteria. Most personal care products are made with a lot of water and a variety of nutrients (consider all of the natural oils and botanicals in Honest products!) which makes an incredibly hospitable breeding ground for microorganisms. What’s worse – the product might smell and look just fine, but be swarming with bacteria or fungi that are dangerous to your health. Effective preservatives are vital for ensuring safety!
Why we use it: We use phenoxyethanol in a very low concentration as a preservative in 5 of our products (Stain Remover, Multi-Surface Spray, Dish Soap, Hand Soap & Laundry Detergent) because the most accessible alternatives for these types of formulas include parabens and formaldehyde-releasing preservatives. Both are classes of chemicals with demonstrable evidence of potential health risks, whereas phenoxyethanol is very safe at low levels. It’s been tested on the skin and eyes and it is non-irritating and non-sensitizing at levels of 2.2% or lower while being effective at only 1% concentrations. The European Union and Japan both approve its use up to that 1% level and our formulas fall well below the recommendation at 0.5% or less (depending on the specific product).
Even better, phenoxyethanol doesn’t react with other ingredients, air, or light. This kind of stability makes it an especially effective preservative.
What’s more, it’s included in the Handbook of Green Chemicals and is also Whole Foods Premium Body Care approved. And, their standards, developed by a team of scientists over the course of years, are some of the strictest available. If these two credible sources give it a thumbs-up, we do, too.
Why we’re featuring it today: We regularly hear from customers concerned about this ingredient because there’s quite a bit of online controversy about its safety. You’ll find it being mentioned as everything from a developmental and reproductive toxicant to being linked to cancer. Fundamentally, it’s poorly interpreted science.
Here’s the real deal: Most of the studies that have found significant negative health impacts are based on full-strength or high-dose exposures. In real life usage, exposures are quite small. That’s why it’s approved at levels up to 1%. It’s all about the final formulation.
Think of it like a cupcake recipe. You wouldn’t want to eat a mouthful of salt, or raw egg, or flour, or probably any other ingredient that goes into a cupcake. (Not only would it taste disgusting, eating a bunch of salt or raw eggs could make you sick!) But mixed in just the right amounts, baked just the right way, a cupcake is divine. That’s the magic of chemistry! Product formulations work the same way.
We’d like to point out a study that helped inform our decision to use it – a study conducted on pre-term newborn babies finding a phenoxyethanol-based antiseptic as the preferred, gentle formula that’s quickly metabolized by even a premature baby’s system.
Now, we’re not trying to write-off our customers concerns about this ingredient – honestly, it’s not perfect, but there are not many preservatives that are. Even alcohol can be harsh and has it’s limitations.
Given all this, we recognize that phenoxyethanol isn’t perfect, and we are actually already trying to find a replacement. It’s the spirit of the company and our commitment to you, to always try to do better!
We certainly stand behind the safety of our products, but we know there’s always room for improvement and we take all of our customers’ feedback and concerns to heart.
Have any other questions or concerns about phenoxyethanol? We’re happy to hear them and help you better understand this ingredient!
Learn more:
International Journal of Toxicology Final Report on the Safety Assessment of Phenoxyethanol
CIR Safety Review: The CIR Expert Panel reviewed safety data on Phenoxyethanol and noted that it was practically nontoxic via oral and dermal administration.
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