Ingredient Watchlist
⚠️ Please note: Ingredients aren’t always black and white. I consider the available research, how an ingredient is used, likely exposure and concentration where known, as well as factors such as a company’s transparency, sourcing and manufacturing practices.
An ingredient appearing on my watchlist doesn’t always carry the same weight in every product, so you may see some nuance when I use it to assess and rate individual products.
These are the main antiperspirant ingredients in deodorant, used to reduce sweating. Aluminium salts, such as aluminium chlorohydrate, aluminium sesquichlorohydrate and aluminium zirconium compounds, dissolve in sweat and form a temporary gel-like plug within the sweat ducts. This restricts the amount of sweat that reaches the skin’s surface.
This is different from alum salts, such as potassium alum and ammonium alum, found in some crystal deodorants. These also contain aluminium, but are chemically different and don’t work in the same way to suppress sweating. There isn’t enough evidence to say they’re safer or more harmful, so I prefer to flag them separately rather than treat them the same as conventional antiperspirant aluminium compounds.
Aluminium is a light metal that can accumulate in the body with sufficient exposure, and high levels can affect the nervous system. However, how much aluminium is actually absorbed through the skin from antiperspirants appears to be very low, and the health effects of everyday antiperspirant use remain debated.
This study states that ‘elevated aluminium content has been found in the brains of persons with Alzheimer’s disease. It remains unclear whether this is a cause or an effect of the disease. There is conflicting evidence on carcinogenicity. The contention that the use of aluminium-containing antiperspirants promotes breast cancer is not supported by consistent scientific data.’ It also concludes with this statement: ‘Large-scale epidemiological studies of the relationship between aluminium-containing antiperspirants and the risk of breast cancer would be desirable’.
This research paper discusses that ‘no significant evidence suggests that aluminium applied to the skin can enter the bloodstream. If any aluminum does enter the body through dermal absorption from cosmetics or antiperspirants, the quantity is insufficient to cause significant accumulation’.
I think it’s worth looking at both sides of the argument. There are enough unanswered questions for me to opt for aluminium-free (DIY) deodorants for everyday use, and I’m also comfortable letting my body sweat rather than routinely suppressing it. That said, I do believe that a fragrance-free aluminium-containing roll-on antiperspirant might be a good option on the days where you really need to avoid sweat and potential odour – if you must. Remember the 80/20 rule, and pick your battles (especially if you have family members – husbands and sons, for me – that just need a little extra, especially when playing sport or being social on hot Perth days)!
Ammonia can irritate airways, cause eye damage and burn the skin. It is most commonly used in cleaning products such as window sprays, oven cleaners and polishing products. Ammonium hydroxide, essentially ammonia dissolved in water, may also be found in some personal-care products, particularly hair products, and can be used in small amounts as a pH adjuster in skincare and cosmetics. The level of concern depends heavily on concentration and how the product is used. I particularly flag ammonia/ammonium hydroxide in sprays or other products where inhalation is possible.
Ammonia can be produced naturally through the decomposition of organic waste matter, gas exchange with the atmosphere, forest fires, animal and human waste, and more.
It is known to be toxic to aquatic life, and although a great deal of the problem comes from runoff from agricultural lands, animal waste and municipal effluent discharges, it still makes sense to reduce the amount we use at home. Warning: never mix products containing ammonia and bleach, as this can produce toxic gases.
Benzyl alcohol is commonly used as a fragrance ingredient or preservative in cosmetic products. You’ll often see it alongside ingredients like benzoic acid and benzyl benzoate. This study concludes that benzyl alcohol is safe for use in cosmetics at the concentrations assessed. While the Environmental Working Group flags some concerns around use restrictions, organ system effects, and occupational exposure, benzyl alcohol is generally considered low concern at permitted cosmetic concentrations.
It can cause irritation or contact allergy in some people, although sensitisation appears to be uncommon. That said, I wouldn’t discount an otherwise clean product if benzyl alcohol was the only flag, especially in a wash-off product.
Closely related synthetic preservatives used to extend shelf life in both food and personal care products. According to the International Agency for Research on Cancer, BHA is classified as a possible human carcinogen, and several studies suggest it may be associated with effects on the thyroid system, metabolism, growth, neurological function and carcinogenesis. (source) This classification is based on forestomach tumours seen in rodent studies; IARC has since noted the mechanism involved may not be relevant to humans, though the classification hasn’t been revoked.
This research paper states that there is insufficient data available to draw a conclusion regarding the safety of BHA when referring to its endocrine-disrupting effect, but given that some of the population may be exposed to doses above the acceptable daily intake, further research is needed on potential effects of BHA both alone and in combination with natural hormones or other endocrine-disrupting compounds.
BHT seems to be less impactful than BHA, and is not classifiable as to its carcinogenicity in humans, but I try to avoid both of these. You will find BHT in this brand of chewing gum and BHA in this brand of mayonnaise, listed as antioxidants 320 and 321.
Often used in products marketed as natural, this synthetic ingredient is typically used as a surfactant and foaming agent and can be found in body wash, shampoo, toothpaste, dishwashing detergents, pet wash and more. CAPB was named Allergen of the Year in 2004 by the American Contact Dermatitis Society. Originating from coconut oil, this ingredient, which is less irritating than SLS, more likely to cause allergic sensitisation, is not the key concern – rather, it’s the potential impurities left behind by the manufacturing process, such as amidoamine and dimethylaminopropylamine. (source)
This is another ingredient that I would possibly let slide if it was the only questionable ingredient in an otherwise clean product, although we should always be mindful of the interaction between ingredients, both within products and also in our bodies. Keep an eye on this one.
Colours are found in many cosmetics including lip balm, toothpaste, cleanser, toner and more. The issue is that it can be difficult to know exactly where they come from – some may be plant-based, while others may be synthetic or derived from coal tar (a known carcinogen). Coal tar-derived colours are widely used in cosmetics and are generally identified by a five-digit Colour Index (C.I.) number. You may also see U.S. colour names listed, such as “FD&C” or “D&C” followed by a colour name and number. (source)
Did you know some colours are even created from crushed beetles (not joking)!
Some dyes can break down into carcinogenic compounds. Product Safety Australia states that it is only certain azo dyes that are problematic, and that the majority don’t lead to exposure to hazardous aromatic amines. The article also notes that the available evidence suggests problematic azo dyes are not widespread, and that many Australian suppliers already have systems in place to reduce the risk of overseas manufacturers using the wrong dyes. Still, until all suppliers have strong systems in place, I’m personally a little wary.
Sometimes a pop of colour (in a coated mica, for example, in a goop or fun dough recipe) is a concession I’ll make, but generally I prefer to avoid them.
When you see certain ingredient names ending in or containing ‘eth’ (such as steareth, laureth, ceteareth and ceteth), be alert, as these commonly indicate an ethoxylated ingredient – a process where chemicals are reacted with ethylene oxide to make them less harsh. However, the letters ‘eth’ appearing somewhere in an ingredient name doesn’t automatically mean it has been ethoxylated. Likewise, not all ethoxylated ingredients contain ‘eth’ in their name; polysorbates, for example, are also ethoxylated.
Ethoxylated ingredients are generally considered low concern on their own. However, unless companies have stringent manufacturing and purification processes in place, small amounts of 1,4-dioxane (a probable human carcinogen) and ethylene oxide (a known human carcinogen) may remain in the product. (source)
The only way to know for sure is to contact the manufacturer and investigate further. Not all ‘eth’ ingredients are ethoxylated or need to be avoided, but recognised ethoxylated ingredients are worth being aware of and researching further (more on that coming up).
Most common are MEA/TEA/DEA – abbreviations for monoethanolamine, diethanolamine & triethanolamine (there are plenty of other names though, so it’s safest to look for any ingredients containing the abbreviations MEA/TEA/DEA, such as cocamide MEA). This group of chemicals are typically used as surfactants and pH adjusters. You might see them in cleansers, shampoo and make-up, among other products.
Research suggests that ‘TEA, DEA, and MEA are safe for use in cosmetic formulations designed for discontinuous, brief use followed by thorough rinsing from the surface of the skin. In products intended for prolonged contact with the skin, the concentration of ethanolamines should not exceed 5%. MEA should be used only in rinse-off products. TEA and DEA should not be used in products containing N-nitrosating agents, which may create nitrosamines. Nitrosamines are a class of more than a dozen different chemicals, which the International Agency for Research on Cancer lists individually as possible and known carcinogens.
With so many conditions and unknowns, I prefer to avoid all products containing these compounds.
Formaldehyde is classified as a known human carcinogen and is also associated with irritation to the eyes, nose, throat and skin, as well as asthma and respiratory symptoms, particularly at higher levels of exposure or with inhalation exposure. (source)
Even when formaldehyde is not intentionally added to a product, small amounts may be released over time by certain preservatives, including DMDM hydantoin, diazolidinyl urea, imidazolidinyl urea, methenamine and quaternium-15. These ingredients are known as formaldehyde-releasing preservatives and are used to help prevent the growth of bacteria, mould and yeast in cosmetic and household products. (source)
You may remember the “Brazilian Blowout” hair straightening trend around 2010, marketed as formaldehyde-free while delivering dramatically relaxed hair for months at a time. I remember it well because I tried it myself. The ACCC later found that some products contained much higher levels of formaldehyde than expected, up to 50x higher, despite formaldehyde-free claims. They stated that there was ‘a substantial degree of scientific evidence that formaldehyde can be a dangerous substance, can be toxic, allergenic and carcinogenic, and when inhaled can cause headaches, a burning sensation in the throat and difficulty with breathing’. (source) Once restrictions tightened and formulations changed, the treatments reportedly became less effective and less popular.
Fragrance is top of my list of ingredients to avoid where possible. It’s added to just about everything – from hand wash and shampoo, to window sprays and fabric softeners, to shoes and toys (have a read of this blog if you fancy some extra awareness; I have found fragrance in panty liners, pillows and jigsaw puzzles – sadly a true story!)
Fragrance formulations may contain a combination of natural and synthetic ingredients designed to create or mask scent. For some people, fragranced products have been associated with adverse effects such as headaches, migraines, asthma symptoms, respiratory irritation, skin irritation and allergic contact dermatitis. (source)
Sensitivity varies significantly from person to person, with some people experiencing little to no reaction and others finding fragranced products highly triggering. This Australian study found that over half of people with asthma reported adverse health effects after exposure to fragranced consumer products, including asthma attacks, breathing difficulties and migraines. The study also found that almost 20% of asthmatics reported taking time off work or losing a job due to fragranced products in the workplace. (source)
Air fresheners and other fragranced indoor products can also release volatile organic compounds (VOCs) into the air, some of which may react with indoor pollutants to form secondary compounds such as formaldehyde. (source)
One of the biggest concerns surrounding fragrance is ingredient transparency. In many countries, fragrance formulations are protected under trade secret laws, meaning companies are not required to disclose every individual chemical used to create a scent. (source)
A single fragrance blend may contain dozens or even hundreds of different compounds.You may also see individual fragrance compounds listed separately on an ingredient label, including limonene, linalool, citral, citronellol, geraniol, coumarin, alpha-isomethyl ionone and hexyl cinnamal. Some occur naturally in essential oils, some may be synthetically produced, and some can be either, so seeing one of these names doesn’t necessarily tell you where it has come from. Many are required to be individually declared because of their potential to cause allergic reactions or skin sensitisation.
I don’t automatically view a naturally occurring fragrance compound such as limonene or linalool in an essential oil in the same way as an undisclosed parfum blend. Context matters. If a product simply lists ‘fragrance’ or ‘parfum’, we generally don’t know everything that mixture contains. If the manufacturer identifies the scent as coming from essential oils and lists their naturally occurring fragrance compounds, there is much greater transparency, although essential oils can still cause irritation or sensitisation in some people.
You may also come across individual synthetic fragrance materials, such as tetramethyl acetyloctahydronaphthalenes (OTNE) or acetyl cedrene. These are worth recognising as fragrance ingredients even when the word ‘fragrance’ isn’t immediately beside them.
If you haven’t yet watched the documentary Stink!, produced by John Whelan, I highly recommend it. The documentary explores fragrance transparency and chemical disclosure laws after a dad started asking questions when his daughter opened a pair of strongly scented pyjamas at Christmas. I’d even go as far as saying you could turn it into a movie night with the whole family, particularly reluctant-to-listen family members – advice is so much easier to swallow when someone else is giving it, right?
Glycols are commonly used in cosmetics as solvents, humectants and texture enhancers, helping products retain moisture, improve spreadability and dissolve ingredients effectively. Common examples include propylene glycol (PG), butylene glycol, dipropylene glycol and hexylene glycol.
Glycols are generally regarded as low concern in cosmetics and are widely used across the cosmetic, food and pharmaceutical industries. However, some people choose to flag glycol compounds due to concerns around irritation, enhanced penetration and their highly processed, often petrochemical-derived nature.
Certain glycol-based ingredients, such as polyethylene glycol (PEG) compounds (see PEG compounds 👆) and polypropylene glycol (PPG) derivatives, undergo additional chemical processing during manufacture. PEG compounds are produced through a process called ethoxylation (see ‘eth’ ingredients 👆), which can raise further concerns for some consumers around manufacturing by-products and contaminants unless carefully purified. Unlike PEGs, PPGs are not necessarily ethoxylated; they are generally regarded as non-toxic and non-carcinogenic, however concerns around irritation remain. (source)
Not all glycols will need to be avoided, but they are worth being aware of and researching further if this is important to you.
Commonly used as preservatives in products such as shampoos, conditioners, cleaning products, shaving creams and detergents, MIT and MCIT help prevent the growth of bacteria, mould and yeast.
These preservatives are widely recognised as common causes of allergic contact dermatitis and skin sensitisation, particularly in leave-on products and in people with sensitive or eczema-prone skin. Concerns have also been raised around inhalation exposure in occupational settings and toxicity to aquatic organisms. (source)
Due to increasing allergy and sensitisation concerns, methylisothiazolinone (MIT) has been under regulatory scrutiny. The European Union banned MIT in leave-on cosmetic products from 2017 and restricted its use in rinse-off products to very low concentrations. (source) Other safety bodies, including the Cosmetic Ingredient Review (CIR) Expert Panel, have concluded that MIT may be safe in rinse-off products within regulated concentration limits, and in certain leave-on formulations when assessed to be non-sensitising. (source)
Methylchloroisothiazolinone (MCIT), particularly when combined with MIT, has also been associated with allergic reactions, especially during the 1980s and 1990s when higher concentrations were more commonly used in cosmetic products.
Canada has prohibited the use of MIT/MCIT in leave-on products intended for children under three years of age, and restrictions also apply to other leave-on cosmetic products. (source)
Not everyone will react to these preservatives, but they are worth being aware of, particularly for those with sensitive or reactive skin.
Mineral oil is a petroleum-derived ingredient commonly used in cosmetics and personal care products as an emollient, moisturiser and skin protectant. You might find it in baby lotions, lip balms, lipsticks, moisturisers and massage oils. It works by forming a barrier on the skin.
While highly refined cosmetic-grade mineral oil is generally regarded as safe for use, the degree of refining and purity matters. Untreated or inadequately refined mineral oils may contain potentially harmful impurities such as PAHs (polycyclic aromatic hydrocarbons) (source), some of which are carcinogenic.
According to the EWG, mineral oil is medium health priority and suspected or measured to accumulate in people (source). The European Union also requires that the full refining history of petrolatum be known and that it be shown to be non-carcinogenic before it can be used in cosmetic products. (source)
The ingredient list generally doesn’t tell us the degree of refining or purity, so this isn’t something that’s easy for consumers to determine from the label alone. That said, highly refined mineral oil used in regulated cosmetic products is considered low concern.
Not all products containing mineral oil need to be avoided, but it is worth being aware of if you prefer to use naturally derived ingredients or are looking to minimise your use of petroleum-based compounds.
Parabens are synthetic preservatives commonly used in cosmetics, personal care products and some pharmaceuticals to prevent the growth of bacteria, mould and yeast. Common examples include methylparaben, ethylparaben, propylparaben and butylparaben. Research has found parabens in the urine of 92–97% of people studied, demonstrating widespread exposure and absorption. (source)
These preservatives have received significant media attention over the years, and many major brands have reformulated products to remove them. Parabens are known to exhibit weak oestrogen-like activity in human breast cancer cells grown in a laboratory. The parabens were able to bind to oestrogen receptors, activate oestrogen-responsive genes and stimulate cell growth, with butylparaben showing the strongest effect and methylparaben the weakest. (source) This has led to concerns about their potential role as endocrine-disrupting chemicals, although whether these laboratory findings translate into meaningful effects in humans requires further research.
This review concluded that parabens have a low toxicity profile and that the weak oestrogen-like effects seen in laboratory studies are far weaker than natural oestrogen and unlikely to pose a risk at typical cosmetic exposure levels. It also noted that paraben sensitisation is most often reported when products are applied to damaged or broken skin such as eczema-affected skin, dermatitis, cuts, scrapes or other skin barrier disruption, although overall rates of sensitisation appear to be low.
The 2010/2011 Scientific Committee on Consumer Safety (SCCS) accepted that parabens have weak hormone-like activity and that some animal studies had raised concerns about reproductive effects, particularly for propylparaben and butylparaben. While methylparaben and ethylparaben were considered safe at current cosmetic use levels, the committee recommended stricter limits for propylparaben and butylparaben as a precautionary measure. (source)
The jury is out for me; I prefer to avoid all parabens.
PEGs (polyethylene glycols) are petroleum-derived compounds commonly used in cosmetics as thickeners, solvents, softeners, moisture-carriers and penetration enhancers. You might find them in many cream-based products and see ingredients such as PEG-20, PEG-40 or PEG-120 written on a label.
PEG compounds are generally regarded as safe for use in cosmetics when properly manufactured and purified. However, because PEGs are produced through a process called ethoxylation, concerns remain around potential contamination with small amounts of ethylene oxide and 1,4-dioxane – chemicals classified as known or probable human carcinogens. Unless a company has strict purification standards in place, consumers have no easy way of knowing whether trace contaminants are present. (source)
PEGs are also known for their ability to increase the permeability of the skin, allowing ingredients to penetrate more deeply. While this can improve product performance, some people choose to avoid PEGs and related glycol compounds due to concerns around irritation, enhanced absorption and their highly processed, petrochemical-derived nature.
Generally speaking, larger PEG compounds tend to sit more on the surface of the skin, while smaller PEG compounds may penetrate more deeply and are more often associated with absorption concerns. For example, PEG-20 may penetrate the skin more readily than PEG-120. (source)
Extra caution is often advised when applying products containing PEGs to broken or compromised skin, including eczema-affected skin, scratches, grazes or broken pimples, as absorption may increase when the skin barrier is impaired. (source)
Not all PEGs will need to be avoided, but they are worth being aware of and researching further if this is important to you.
Petroleum distillates are a broad group of petroleum-derived chemicals commonly used as solvents in cleaning, automotive and industrial products. You may find them in products such as stain removers, spot cleaners, degreasers, furniture polishes, adhesive removers and some heavy-duty household cleaners.
Occupational studies have linked repeated exposure to solvent mixtures containing petroleum naphtha with headaches, fatigue, impaired concentration and respiratory irritation, while environmental concerns exist due to their potential toxicity to aquatic organisms. (source)
Some petroleum distillates have been classified as potential carcinogens unless they can be shown to contain very low levels of benzene and other hazardous impurities. (source)
If you’re concerned about petroleum-derived solvents, check the product’s Safety Data Sheet (SDS), where ingredients such as petroleum distillates, naphtha or hydrocarbon solvents may be listed. You can also contact the company directly for further information.
Phthalates are a group of chemicals commonly used to make plastics more flexible and durable and may be found in fragrance, nail polishes, medical equipment, PVC clothing and toys, and more. (source)
Phthalates may be added to fragrance formulations to help scents last longer, and because fragrance blends are often protected as trade secrets, they are not always individually disclosed on product labels. Phthalates are used in plastics to increase flexibility and in nail polish to reduce cracking.
Certain phthalates have attracted significant scientific and regulatory attention due to concerns about their potential endocrine-disrupting properties and possible effects on reproduction and development. This review of human studies found that some phthalates, particularly DEHP and DBP, were associated with changes in testosterone levels, semen quality and male reproductive development. The authors concluded that exposure to certain phthalates at levels commonly seen in the population may have reproductive effects, although the strength of evidence varies between individual phthalates, and not all phthalates carry the same level of concern.
If you’re trying to reduce your exposure to phthalates, fragrance can be one area worth investigating further. Contacting the manufacturer is often the only way to determine whether specific phthalates are present in a product.
Phenoxyethanol is a synthetic preservative commonly used in cosmetics and personal care products, from moisturisers and shampoos to baby wipes and cosmetics, to prevent the growth of bacteria, mould and yeast. It is popping up more and more as an alternative to parabens and has been associated with skin and eye irritation in some individuals, with concerns raised about potential effects on organ systems at high levels of exposure.
According to the European Scientific Committee on Consumer Safety, phenoxyethanol is safe for consumers of all ages, including children, at concentrations of up to 1%. Adverse effects observed in animal studies generally occurred at exposure levels far higher than those experienced through normal cosmetic use. (source)
While phenoxyethanol appears to be safe within current regulatory limits, I remain concerned about the cumulative effect of repeated exposure from multiple products used throughout the day.
Added to soften water and improve cleaning power, phosphates have historically been used in washing powders, dishwashing detergents and other cleaning products. Many modern laundry and dishwashing products no longer contain added phosphates, particularly in countries where restrictions have been introduced, but it still pays to keep an eye out.
High levels of phosphorus in waterways can be harmful to the environment, encouraging algal blooms that may produce toxins harmful to human and animal health. The biggest sources of phosphorus pollution are generally from agricultural runoff, urban stormwater, leaking septic systems and discharges from sewage treatment plants. (source) Historically, phosphate-containing detergents also contributed to this problem, which led to restrictions in many regions.
Propane, butane and isobutane are compressed gases commonly used as propellants in aerosol products such as deodorants, hair sprays, dry shampoos and household sprays. Their primary role is to help dispense the product from the can.
Because butane and isobutane are gases, they quickly disperse into the air when aerosol products are used. While this can contribute to inhalation exposure to trace contaminants such as 1,3-butadiene, studies suggest that cosmetic products contribute relatively little to overall exposure, although the cumulative impact of using multiple aerosol products has not been fully quantified. (source)
Canada restricts butane and isobutane in cosmetics if they contain more than 0.1% of 1,3-butadiene, a contaminant that can be produced during refining and is classified as a known human carcinogen. (source)
While these propellants are generally considered safe for use in cosmetics when regulatory standards are met, I prefer to minimise my use of aerosol products as they are easily inhaled and contribute to indoor air pollution. If you choose to use aerosol products, consider spraying them in a well-ventilated area (or outside) and avoiding direct inhalation where possible (I would personally still hold my breath!).
You might find You might find higher-concern QUATs listed as benzalkonium chloride, alkyl dimethyl benzyl ammonium chloride (ADBAC) or didecyldimethylammonium chloride (DDAC) in disinfectants, sanitisers, fabric softeners and some household cleaning products.
QUATs are not considered toxic after short-term exposure, and severe effects generally occur only after significant exposure. However, concerns remain around repeated exposure, with studies linking some to skin and respiratory irritation, and an increased risk of asthma. (source)
Note that not all QUATs are the same. Different compounds have different properties, uses and safety profiles. For example, Quaternium-15 is a formaldehyde-releasing preservative (see above), while others have been highlighted as having potential for reproductive toxicity. (source) Some lower-concern QUATs, such as cetrimonium chloride, behentrimonium chloride, behentrimonium methosulfate, Quaternium-18 and common polyquaterniums, are used as conditioning or antistatic ingredients in shampoos, conditioners and other personal-care products. I still flag these, but they aren’t automatic deal-breakers.
Just be alert and aware.
Siloxanes are an umbrella term for a group of silicone-based chemicals commonly used in moisturisers, hair products, deodorants and cosmetics. They are often added to improve spreadability, create a smooth feel on the skin and hair, reduce moisture loss and improve product performance.
Not all siloxanes are the same. Some, such as dimethicone, are generally regarded as low concern and are widely used in cosmetic products. Others, such as cyclotetrasiloxane (D4), cyclopentasiloxane (D5) and cyclohexasiloxane (D6), have attracted regulatory attention due to concerns about their persistence in the environment, potential to bioaccumulate and possible effects on reproduction observed in some animal studies.
However, after reviewing the available evidence, the Canadian Government (which generally take a precautionary approach to chemical regulation) concluded here that the siloxanes assessed were not harmful to human health or the environment at current levels of exposure.
If you’ve ever made soap, you’ll know sodium hydroxide (lye) is the ingredient needed to turn oils into soap through a process called saponification. When soap is made correctly, there shouldn’t be any lye left in the finished product, so there is no need for concern if you see it listed on a soap label.
You may also find sodium hydroxide in some cosmetics as a pH adjuster, and in stronger concentrations in products such as drain cleaners and oven cleaners.
According to the US Centers for Disease Control and Prevention (CDC), sodium hydroxide does not produce systemic toxicity, but it is highly corrosive and can cause severe burns to any tissue it comes into contact with. It poses a particular risk to the eyes and can cause serious eye damage. (source) So, if you decide to DIY soap at home, please be careful.
Found in household chlorine bleach, sodium hypochlorite is commonly used for whitening, stain removal, cleaning and disinfection.
According to this research paper, ‘household bleach, used according to label directions, including recommended ventilation and protection, is surprisingly non-toxic to humans. This may lead to complacency. Misapplied, especially when mixed with other substances, it can be harmful or even lethal.’ The authors also noted that bleach was the leading cause of household cleaning product injuries in young children, most commonly through accidental ingestion.
While household bleach appears to be relatively safe when used according to directions, repeated exposure has been linked to respiratory issues such as asthma and other breathing problems, particularly among cleaners and healthcare workers. Other reported symptoms include nausea, vomiting, dizziness, breathing difficulties, headaches and coughing. Poor ventilation, overuse, incorrect dilution and mixing with other products can all increase the risk of adverse effects. (source)
For me, the biggest concern with bleach is that we’re often using it in small, enclosed areas such as bathrooms, where ventilation may be poor. I also worry that people can become complacent and start mixing products without understanding the risks. If you choose to use bleach, never mix it with acids, ammonia or other cleaners, as dangerous gases can be produced. Follow the label directions carefully, ensure good ventilation and store it well out of reach of children.
Sodium coco sulfate (SCS) is a cleansing agent commonly used in shampoos, body washes, soaps and other personal care products. It is often marketed as a more natural alternative to sodium lauryl sulfate (SLS) because it is typically derived from coconut-based fatty acids. However, it still undergoes significant chemical processing and is chemically very similar to SLS.
Both SCS and SLS belong to the same family of sulfate surfactants and may cause skin, scalp or eye irritation in some people, particularly those with sensitive skin. Regulatory and industry safety assessments have concluded that these ingredients are safe for use in cosmetics at current concentrations. (source)
One study found that SCS may be slightly less irritating than SLS, but both ingredients showed the potential to affect the skin barrier and skin cells in laboratory testing. Overall, the evidence suggests that SCS is not necessarily a dramatically gentler alternative to SLS, despite often being marketed that way. (source)
Personally, I think SCS has benefited from a bit of a ‘health halo’ because it comes from coconut oil and sounds more natural. But the jury is out for me. Whether you choose to avoid it is up to you, but I wouldn’t automatically assume it is dramatically different to SLS simply because the name sounds nicer.
Found in a wide range of personal care and cleaning products, sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES) are surfactants that help water mix with oils and dirt so they can be washed away. They are also responsible for much of the foam and bubbles that people often associate with cleaning power.
The main concern with SLS seems to be skin and eye irritation rather than long-term toxicity. This review concluded that SLS is safe for use in household cleaning products when properly formulated, and that many of the more serious health claims made about the ingredient are not supported by the available scientific evidence.
The Cosmetic Ingredient Review states that: SLS appears to be safe in formulations designed for discontinuous, brief use followed by thorough rinsing from the surface of the skin. In products intended for prolonged contact with skin, concentrations should not exceed 1%. SLES may induce eye and skin irritation, however, on the basis of the available information, concludes that it is safe as presently used in cosmetic products.
SLES differs from SLS in that it undergoes a manufacturing process called ethoxylation. As discussed earlier (see ‘eth’ ingredients 👆), this process can result in contamination with trace amounts of toxic by-products, ethylene oxide and 1,4-dioxane, unless the ingredient is purified by the manufacturer. (source) At the end of the day, whether you choose to avoid SLS and SLES is up to you, but there are plenty of brands successfully formulating products without them so you have options.
Some chemical sunscreen filters, particularly oxybenzone, octinoxate, octocrylene and homosalate, have made headlines due to concerns about skin absorption, hormone-disrupting effects, allergic reactions and environmental impacts. (source) Studies have shown that these ingredients can be absorbed through the skin and detected in blood, urine and breast milk after sunscreen use. (source) Note that absorption does not automatically mean harm and more studies are needed.
Several common chemical sunscreen filters can be absorbed through the skin and detected in the bloodstream after use. However, this 2025 review by the Australian Therapeutic Goods Administration (TGA) found most of the filters reviewed to be low risk at current use levels, but recommended tighter permitted concentrations for oxybenzone and homosalate specifically, after their safety margin for whole-body use fell below the TGA’s own threshold. The benefits of sunscreen use for skin cancer prevention still outweigh the potential risks for the filters the review cleared.
This review discusses organic UV filters such as avobenzone, homosalate, octisalate, octocrylene and octinoxate, which are widely used in sunscreens, cosmetics and other consumer products, and are now commonly detected in aquatic environments around the world. Experimental studies suggest some of these ingredients may influence sex hormones and thyroid function, although human evidence remains limited. The authors concluded that further research is needed to better understand the potential health and environmental impacts of these UV filters.
Personally, I think sunscreen is one area where risk versus benefit matters. I live in Australia and the incidence of skin cancer is huge, so there is a need to be mindful of excessive UV exposure. I do believe we need safe sun exposure though – let’s not fear the sun!
For me, the first line of defence is always covering up in peak sun with clothing, hats and shade where practical. When sunscreen is needed, I personally prefer mineral-based options. There are now plenty of effective mineral sunscreens available, and that’s my preference. I even have a DIY zinc oxide sunscreen balm recipe here.
Triclosan (and its cousin triclocarban) are antimicrobial ingredients added to products such as antibacterial hand washes, soaps, toothpastes and deodorants to help reduce bacterial growth. They have also been used in a range of consumer products including plastics, textiles, toys and kitchenware. (source) Triclosan was first registered as a pesticide in 1969. (source)
Over the past decade, these ingredients have been phased out of most mainstream products after they attracted attention due to concerns about their potential effects on human health. Studies have shown that they are absorbed through the skin and oral tissues and have been detected in human urine, blood and breast milk following exposure. (source)
Another concern is that widespread use of these antibacterial ingredients may contribute to bacterial resistance and reduce the effectiveness of some antibiotics. (source)
Triclosan has been removed from many antibacterial hand washes because studies found it was no more effective than plain soap and water for everyday use. (source) As a result, many manufacturers have reformulated products and their use has declined significantly in recent years – I could only find a few products online containing either ingredient (for example, this Dettol soap at Woolworths).
From an environmental perspective, triclosan can persist in waterways and may accumulate in aquatic organisms, raising concerns about its impact on aquatic ecosystems. (source)
For me, this one is a solid no thanks!
You may also see this ingredient listed as 2-butoxyethanol ethylene glycol monobutyl ether. It is commonly used as a solvent in products such as spray cleaners, degreasers, paint strippers, varnishes, surface coatings and some household cleaning products.
Studies suggest that exposure to 2-butoxyethanol may cause irritation of the eyes, skin and respiratory tract, along with symptoms such as headaches and nausea. Most of the more serious health effects have been observed in workers exposed to high levels or in animal studies using much larger doses than consumers would typically encounter. While animal studies have raised concerns about effects on red blood cells and reproduction at high exposures, there is currently no clear evidence that 2-butoxyethanol causes cancer or reproductive harm in humans. (source)
Disclaimer:
This Ingredient Watchlist reflects my personal approach to ingredient awareness and the ingredients I personally choose to avoid, minimise or look into further. It is intended as a guide, not a definitive list of ingredients that are safe or unsafe.
I’ve included research and information to explain why an ingredient is on my radar, but the presence of an ingredient doesn’t automatically mean a product is harmful. Concentration, frequency of exposure, how a product is used, whether it’s inhaled, rinsed off or left on the skin, and the overall formulation can all matter.
Research evolves, regulations change and new information becomes available, so this list may change over time. Where evidence is mixed or uncertain, I’ve tried to make that clear rather than present an association or potential concern as proven harm.
My aim with this watchlist is simply to help you recognise ingredients, understand why they may be worth a closer look, and make your own informed choices. You don’t need to avoid everything, all the time. I certainly don’t. The 80/20 approach applies here too.