Potassium Sorbate: A Safe Ingredient For Acne… Or Is It?

Compared to horrors such as BPA or fluoride, potassium sorbate has a shining reputation as one of the kindest, gentlest cosmetics ingredients.

In internet articles bashing artificial preservatives, potassium sorbate is commonly recommended at the end as a safe one.

But is it? My main recommendation is to avoid chemical concoctions with 100 ingredients anyway, but potassium sorbate occasionally pops up in natural acne remedies.

Aloe vera is one example. The gel is notoriously unstable, deteriorating hours after being squeezed from the leaf. Therefore, it’s a vital additive to understand, so that you don’t trip up and land face first in a puddle of acne.

Is potassium sorbate riskier than everybody thinks? To give you a clue, it’s no mercury, but potassium sorbate has one sneaky danger which raises a question mark.

 

What is it?

Potassium sorbate is simply sorbic acid with a potassium molecule attached. In studies, potassium sorbate and sorbic acid are sometimes used interchangeably.

The story started in 1850 when German scientist A.W. Hoffmann extracted natural sorbic acid from Rowan berries, the red-coloured fruit of the mountain ash tree. In European folklore, this tree was dubbed “Thor’s helper” and had the power to ward off evil influences. Villagers even carried the tree’s wood with them to protect against witches.

Little did Dr Hoffmann realise that his discovery would eventually be one of the world’s top food preservatives. In 1890, sorbic acid’s molecular structure was determined, and by the 1940s it was appearing in foods so fast, it was like it had become sentient.

Today, artificially synthesised potassium sorbate appears in…

FOODS: ice cream, yogurt, cheese, dried meat, apple cider, pickles, soft drinks.

COSMETICS: eye shadow, moisturisers, contact lens solution, shampoos.

A 2019 Italian study found that 22% of randomly selected cosmetics contained potassium sorbate. It’s popular in winemaking, to prevent yeasts from multiplying once the initial fermentation phase is over, leaving the remaining yeast to slowly die. It’s particularly popular in sweet wines and sparkling wines, although misjudging the quantities can create an unpleasant geranium tang.

 

The first danger – inflammation

Sorbic acid might have been isolated from a swaying, red-berried tree initially, but nowadays, all commercial potassium sorbate is manufactured from petroleum in a laboratory. It is synthetic, a chemical through and through, but does potassium sorbate cause inflammation?

The happy answer is no. Potassium sorbate seems to be very safe.

Firstly, we have a fantastic study not just for potassium sorbate, but dozens of other inflammatory chemicals. It was an epic involving 14,911 Belgians stretching across 26 years. Scouring through doctors logbooks, scientists noted every time a popular cosmetics additive triggered an explosion of irritation in dermatitis patients.

One villain was the 2013 “allergen of the year” methylisothiazolinone, found in sanitary products, paint and baby wipes. This triggered dermatitis in 76 out of 308 cases, or 24.68%. Also highly ranked were p-Phenylene diamine and toluene-2,5-diamine, both found in strong hair dyes and scoring 21.40% and 41.04% respectively.

As for potassium sorbate? It worsened dermatitis in 2 out of 146 people, or 1.37%. Better, these were people who already have compromised skin barriers, and immune systems ready to explode.

Other experiments were just as safe. You should be just as sceptical of gigantic dermatology bodies as new age gurus raving about colloidal silver, mainly because they treat each chemical in isolation rather than considering the combined consequences.

Nevertheless, the Cosmetic Ingredient Review (CIR) concluded that potassium sorbate rarely causes irritation. So did the FDA, and even the stricter Environmental Working Group rated it 3/10 on their hazard scale. A study did document a lone milk factory worker who developed dermatitis from potassium sorbate, but that fits in well: inflammation can happen, but rarely.

The worst study is one where potassium sorbate increased NF-KappaB, the master inflammatory molecule. However, in the natural acne remedies that I recommend, there’s a 75% chance of anti-inflammatory properties which can counteract it anyway. Aloe vera is the classic example, with anthraquinones, lupeol, and flavonols galore.

Then there’s one final safety factor: you can see irritation with your eyes, and know when to stop instantly…

 

Does it kill an invisible acne ally?

…which is more than can be said about our second danger, which is by far the riskiest.

If potassium sorbate carved out its place in the food industry by deleting microorganisms upon contact, then logic holds that it might destroy the body’s beneficial bacteria too.

For 10 years, the research on gut bacteria has gathered pace into a flood. Healthy strains can increase serotonin, pump out anti-inflammatory molecules like butyrate and enhance acne nutrient absorption. Only recently has the eye of attention swivelled to beneficial skin microorganisms, which may be just as important. For example, it was found that a soil bacteria called nitrosomonas eutropha consumes ammonia in sweat and creates antibacterial by-products. Lactobacillus rhamnosis can generate lactic acid, which lowers the PH of skin pores and makes them inhospitable to acne bacteria.

Could potassium sorbate grind this potential to a halt? The answer right now is that we don’t know.

For example, this 2005 study was reassuring. Potassium sorbate was sprayed into bacteria-rich biolive yoghurt, and left to ferment for 30 days. At all time intervals, potassium sorbate suppressed villainous microorganisms such as aerobic spore-forming bacteria, psychrotrophic bacteria, yeasts and moulds. Miraculously though, lactobacillus and streptococcus were left untouched, which are yoghurt’s main health-giving strains.

In this study though, three common preservatives were fed to human volunteers: sodium nitrate (the cancerous bacon villain), sodium benzoate, and potassium sorbate. Worryingly, anti-inflammatory strains were the most vulnerable, including the heavily researched Clostridium tyrobutyricum or Lactobacillus paracasei, contradicting the yogurt study.

The conclusion was grim: “even low levels of additives may modify the composition and function of gut microbiota and thus influence the host’s immune system“. In a mouse study, the same three additives were tested. At average European exposure levels, potassium sorbate distorted the balance of gut bacteria, increasing P species, which correlate closely to immune system problems. This family includes the feared salmonella and heliobacter pylori.

 

The threat is real

Logically, this could benefit acne too, by wiping out p.acnes bacteria, although there are no studies testing it. There are positive studies against the secondary acne player s. aureus. 

The first problem is that the intricacies of potassium sorbate are not fully understood. The second is that the intricacies of skin bacteria are not fully understood. There are two layers of mystery, and unlike red and painful inflammation, you can’t keep tabs on it. You can’t watch your friendly skin bacteria melt away with your own eyes.

Apply potassium sorbate daily, in the form of aloe vera gel, and your skin microbotia could steadily unbalance until one day, p.acnes bacteria finds it much easier to take over. Different strains exist in a natural equilibrium. For example, staphylococcus epidermidis naturally produces succinic acid by fermenting glycerol in your skin. This succinic acid enters p.acnes’ cell membrane and splits into anions which lower the PH and cause catastrophic damage. Even within p.acnes, strains from the friendly group 2 manufacture peptides called acnecins which take out harmful group 1a strains.

It’s the same reason why I recommend against antibiotics. Raining down on your skin bacteria with indiscriminate weapons is always a risky business, when we understand so little about it.

And that’s the point: potassium sorbate is indiscriminate. It doesn’t specialise in one mechanism. Potassium sorbate can…

ONE: inhibit permeases, enzymes which transport energy sources through the cell membrane to where bacteria can digest them. These include proteins, glucose, sugar alcohols and fructose.

TWO: physically damage the shape of bacteria, by warping the cell membrane and interfering with cell wall formation and division.

THREE: decrease adenosine triphasphaste (ATP), the fundamental energy form inside all living cells. Sorbate diffuses through the cell membrane and causes an ion imbalance, depleting ATP in the microorganism’s attempt to reverse it.

FOUR: enter the cell membrane and lower the PH of the cytoplasm within.

NOTE: see this review for brain-melting scientific detail. 

Its sheer variety of tactics make potassium sorbate an amazing preservative, but also a risky ingredient for your facial flora. 

 

Acne chemical bingo

So what about the other mainstay acne dangers in the preservative databanks?

Estrogenic properties – its astonishing how many common environmental chemicals have hidden estrogenic properties. Somehow, very few increase testosterone instead, otherwise Olympians would be rolling around in shampoo before their big race. But anyway, artificial substances that stimulate the same bodily receptors as estrogen are called xenoestrogens, or endrocrine disruptors, and the most insidious villains include BPA, pthalates, parabens, and sunscreen chemicals like sulisobenzone and oxybenzone

For potassium sorbate, the truth is that no negative studies on estrogen exist, unless they’re incredibly obscure. It’s also in the clear for breast cancer, which is tightly linked to rampaging xenoestrogens.

European agencies are much stricter about chemicals, and their report has one concise sentence: “Potassium sorbate is not considered to have endocrine disrupting properties “. This is great news for overall health as well as acne.

Collagen depletion – there are numerous ingredients that unexpectedly decrease the youthfulness protein, just like many increase it. For example, sodium fluoride, the favourite industrial waste chemical of toothpaste companies, can decrease the important collagen type 1 alpha 1 (COLT1A1) gene.

Meanwhile the preservative sodium benzoate can drain glycine from the body. During its detoxification, glycine binds to sodium benzoate, forming a complex called hippurate which is easily removable from the bloodstream.

Sodium benzoate is even used to treat hyperglycinemia, a neurological condition in children caused by glycine levels running wild. Alongside proline, glycine is the main protein used to synthesise all collagen, forming 26% of its weight.

So what about potassium sorbate? No negative evidence exists, but neither do any studies proving its safety. Compared to estrogen, my gut feeling is more negative.

Glutathione – the single biggest reason why acne patients underestimate environmental chemicals, aside from when their inflammatory powers join forces. We’ve covered it here loads of times, but maybe 60-70% of contaminants in cosmetics or processed food require glutathione to be detoxified. Glutathione also functions as an antioxidant and therefore, depleting your precious supplies is not advisable.

This study hinted that potassium sorbate is a member of this wicked club. When applied to rat liver cells, the glutathione (GSH) content declined, bottoming out at 6 hours.

Afterwards, they applied a toxic chemical called eicosapentaenoic acid, and the cells had increased vulnerability to lipid peroxidation, or free radical damage. Potassium sorbate could therefore weaken your skin against sunlight and cigarette smoke. Fortunately, this is only one study, and in aloe vera, for example, its natural antioxidants could outweigh the small potassium sorbate concentrations.

We should keep these dangers in our sights, but friendly bacteria remains our number one concern. 

 

What about as a food ingredient?

Almost the exact same rules apply. In fact, the potassium sorbate lurking in dried meats, soft drinks and sauce may be slightly worse because there is direct evidence against gut bacteria.

The good news is that because I advise acne patients to banish most processed foods anyway, you will be automatically avoiding it. There are very few nutritious, acne-friendly staples where potassium sorbate is a factor. For example, soft drinks have other villains such as sugar and aspartame. Dried fruits have the antioxidants but are mega-concentrated in sugar.

Treat days are something we recommend here, but swallowing a little potassium sorbate won’t instantly derail everything. Gut bacteria is a constant tug of war, so even eating a bowl of biolive yogurt will easily counteract it. That’s ignoring probiotic supplements, traditional fermented foods like kefir and sauerkraut, and plant compounds like epicatechin which feed healthy strains.

 

The verdict

It might seem like I was really ranting against potassium sorbate earlier, but it isn’t conclusively in acne jail alongside mercury and fluoride.

That said, no matter how tempting the hundreds of phytonutrients in aloe vera are, we cannot ignore the risks to healthy skin flora. It isn’t proven, but logically, there are no barriers. Furthermore, it’s not like antioxidants or inflammation, where the nutritional goodness will outweigh it.

If you’re into crafting homemade remedies like a mad scientist, you could always mix aloe vera with bio-live yogurt to provide a built in bacterial buffer. Overall though, you shouldn’t ban potassium sorbate outright, but until the crystal ball of acne clears, you should watch your skin with the eye of an eagle whenever using it.

This article has a tragic ending: aloe vera will have to be downgraded slightly as a topical treatment. Not for its inherent properties, but because potassium sorbate is in 95% of products on the market.

 

Thanks for reading!