What is the detergent in soap nuts and how does it work?

What is the soap in Soap Nuts? Soap Bubble Image

Here at PureRescue we believe that plant-based shampoos are better for your hair because they avoid some of the nasty chemicals found in cheap alternatives. They also clean just as well, if not better, than their commercial counterparts. The reason these plant-based shampoos can outclass products made by big chemical companies is because of one or two incredible plants that have soap-like properties. The most prominent and widely-used of them all is appropriately named the soap nut.

The soap nut has enriched countless generations through its ability to clean clothes, bodies and hair. But what is it about this nut that makes it such a good cleanser, if at all?

The science

First of all, we have a little confession to make: The soap nut isn’t actually a nut, it’s a berry. To be fair, this is not a naming scandal, it just that when the small black berry, approximately one inch (2-2.5 cm) in diameter, hardens it ends up looking a lot like a nut. The berry, which grows on the sapindus mukorossi tree in the Himalayas, is deseeded and dried before being used. It contains a natural soap called saponin which functions like a surfactant — i.e. the chemical that binds both with oil and water. Like all surfactants, saponin reduces the surface tension of water, making it easier to get into the fibres your hair to dislodge dirt. When this process is combined with the vigorous movement of your hand, the grime can be rinsed away.

In contrast to commercial shampoos, products containing soap nut do not foam. This can be a little confusing for some consumers because modern marketing has created a strong link in our minds between froth and cleanliness. This is simply not true however — low-foam shampoos have been shown to get rid of grime and grease as well as foamy competitors.

The sustainability

First of all the soap nuts are wild-harvested. They are picked from trees without the use of chemicals, fertilizers and pesticides. That is the fortuitous consequence of the fact that most insects don’t like the taste of saponin. Soap nuts also require very little processing and packaging which means they score really well when it comes to sustainability.

This is no small accomplishment. A carbon footprint study done by Boots in 2008 found that the “raw material extraction” phase was the second biggest contributor to greenhouse gas emissions in the shampoo production process. It contributed approximately 85g of CO2 per 23,5g bottle of shampoo. Because the soap nut eliminates many of the production steps, it allows the environment to breathe just that little bit easier.


Given that the soap nut isn’t actually a nut, even consumers with nut allergies can use it without any apprehension. Soap nuts are naturally hypoallergenic, odorless and particularly gentle on your hair. They are so soft in fact that when soap nuts are used as detergents in washing powders, there is no need for fabric softeners.

A word on aloe vera

Besides the soap nut, aloe vera is also a common addition to plant-based shampoos that deserves a mention here as well. Like its berry counterpart, aloe has a multitude of impressive cleaning properties. These arise primarily from the fact that aloe has a similar chemical composition to keratin — the protein that hair is made of. This means that it is great at rebuilding hair fibres and that it can penetrate the entire length of the hair shaft to repair it.

Aloe also contains 20 amino acids which form the building blocks of the hair and cells in the scalp. Add to that the conditioning properties inherent in aloe and you have an all-round nourishing experience that leaves your hair with a healthy glow.

Photo: Photo by Markus Spiske on Unsplash

Can chemicals in my cosmetics get into my body?

How toxins get into our bloodstream

How toxins get into our bloodstream

The skin is our largest and one of our most important organs. It does the indispensable job of keeping us cool and protecting us against the elements. The only downside to having it is that we have to endure a phase during puberty in which it becomes a pimply repellent against the opposite sex.

But what happens when the skin is not able to carry out one of its key functions? What happens when chemicals manage to break our skin’s defences? Is it possible, for example, for the cosmetics we put on our skin to make it into our bloodstream and cause damage from there?

Skin 101

There are three layers to our skin:

  • a top layer (epidermis),
  • a middle one (dermis)
  • and an inner one (hypodermis).

As you might expect, the top layer is our first line of defence, it has a fat buffer and many blood vessels inside it. This layer is lipophilic (oil-loving) and hydrophobic (resistant to water), a feature which accounts for the fact that we do not fill up with water every time we step into the shower or swim in the ocean. Oils typically make it into the upper layer (penetration) but this is most often as far as they go. The other layers further below have a different chemical composition, making it more difficult for oil to go any deeper.

This means that most oils won’t make it into your bloodstream. There’s too much water in our bodies and too many layers of cells to prevent this. But does this mean that we don’t have to worry about chemicals in our cosmetics? Not quite.


The cosmetics industry has found clever ways of getting past these epidermal security guards: Through a process called emulsification, oil and water are mixed. It’s a bit like how mayonnaise is made — the blending of a water-based ingredient (mustard and lemon juice) with an oil is achieved using an egg yolk, which binds them. Modern cosmetics function similarly. They use emulsifiers to blend oil and water, making it easier to penetrate your skin.

What about the skin’s defences?

The good news is that the skin is savvy enough to deal with even the intruders that come through with emulsifiers. Also, many molecules are simply too big to get through. Others remain on the skin’s surface and still others bind with the skin itself. Those that do seep through will encounter enzymes that break down or inactivate toxic chemicals. There are however some that may do the opposite, i.e. they activate chemicals, making them more toxic. For example, in 1775 Percivall Pott, a British doctor, found that contact with polycyclic aromatic hydrocarbons in soot was causing chimney sweeps to get cancer.

Absorption and penetration

When it comes to chemicals in cosmetics, it is important to distinguish between penetration (simply getting under the skin) and absorption (breaking into the bloodstream). Penetration is not necessarily problematic because once a substance enters the body, it may be turned into another chemical or metabolized by the body.

The other alternative is that it accumulates. This is where things get tricky because when it comes to toxicity often the dose is the deciding factor (many otherwise non-harmful substances can become toxic at high concentrations). Our bodies have a theoretical threshold at which the accumulated amount of a substance becomes unsafe. This point is different for each person.

So the answer to the question, “Does our body absorb what we put on our skin” is “yes and no”. Some substances definitely do make it through — especially if aides like emulsifiers increase absorption rates, but it is hard to provide a generally applicable formula. Governmental bodies like the FDA limit the amount of ingredients that can be used to increase absorption rates, but as discussed here, FDA regulations are not always full-proof.

So what should you avoid?

As mentioned above, exposure is the key factor to consider when it comes to chemicals. For example, something you splash onto your face briefly will have a different effect on your skin compared to a lotion that you put on your body and allow to soak in all day. That is to say, be extra careful with products that are exposed to a large surface area (e.g. body creams, bath salts). Shampoos make it onto that list as well as the foamy residue eventually runs off onto your entire body.

Parabens and formaldehyde are some of the most worrying chemicals you would do well to avoid. Parabens are preservatives which have been shown to be estrogen mimics. These can have adverse effects on your hormonal household, so much so that many of them have been banned by the EU. Formaldehyde has been linked to cancer in a high publicity lawsuit against the multinational cosmetics manufacturer, Johnson & Johnson. Both of these could get into your bloodstream through your shampoo, so it is advisable to get a plant-based alternative for some peace of mind.

Welche Inhaltsstoffe in Shampoos sollte ich während der Schwangerschaft vermeiden?

What shampoo ingredients should I avoid during pregnancy?

Wenn die Schwangerschaftshormone sich erst einmal im Blutkreislauf einer Frau tummeln, sind Heißhunger und Übelkeit nicht die einzigen Folgen. Unglücklicherweise bleiben nicht einmal ihre Haare verschont. Ganz in typischer Manier der Hormone kann sich das auf ziemlich unvorhersehbare Art und Weise äußern. Manche Frauen mit üblicherweise trockenem Haar bekommen dann fettiges, andere haben statt ihrer Naturwellen eher glattes Haar, und wieder andere stellen fest, dass ein Haarfärbemittel zu einem anderen Farbton führt, als sie es gewohnt sind. Ganz zu schweigen davon, dass bei manchen Frauen plötzlich Haare an Stellen sprießen, wie sie es vorher nur beim nervigsten aller Onkel gesehen haben (ganz recht, wir reden vom Haarwuchs am Rücken und gänzlich unerwarteten Stellen im Gesicht.)

Was die Hormone so treiben, kann man leider nicht ändern. Allerdings gibt es während der Schwangerschaft auch Risiken, gegen die man etwas unternehmen kann. Ein Beispiel sind einige der Chemikalien, die in Shampoos enthalten sind und Ihrem Baby schaden könnten. PureRescue hat eine Liste der beunruhigendsten zusammengestellt, die man meiden sollte.


Maura Henninger, eine naturheilkundliche Ärztin aus New York City, hat die Gefahren von Parabenen in einem Interview mit dem Magazin mom diskutiert. Laut Henniger sind Parabene (oft angeführt als Sodium Methylparaben, Methylparaben, Ethylparaben, Propylparaben und Butylparaben) Inhaltsstoffe, die Sie bei Shampoos meiden sollten. Das größte Problem mit diesen Wirkstoffen ist die Tatsache, dass sie dem weiblichen Sexualhormon Östrogen ähneln und es nachahmen. Dr. Henniger warnt, dass „wissenschaftliche Studien zeigen, dass sie den Hormonhaushalt stören können und somit eine Gefahr für die normale Entwicklung des Fötus darstellen.“

Es sind noch weitere wissenschaftliche Studien nötig, um festzustellen, welche Auswirkung Parabene ganz genau auf ungeborene Babys haben. Es ist möglich, dass sie anfälliger für die Auswirkungen von Unregelmäßigkeiten des Hormonspiegels sind.

Vitamin A

Eine Studie in den neunziger Jahren hat gezeigt, dass Vitamin A in übermäßigen Mengen zu angeborenen Fehlbildungen bei Neugeborenen führen kann. Für die Babys von Müttern, die während der Schwangerschaft pro Tag mehr als 10.000 Einheiten Vitamin A – was dem Vierfachen der empfohlenen Tagesmenge entspricht – zu sich nahmen, bestand eine größere Wahrscheinlichkeit, mit Fehlbildungen am Kopf, im Gehirn, dem Herz oder Rückenmark geboren zu werden.

Dabei ist zu beachten, dass diese Studien sich in erster Linie auf Nahrungsergänzungsmittel beziehen. Laut dem Linus Pauling Institute sollten Nahrungsergänzungsmittel unter 3.000 mcg/Tag bleiben. Die in Shampoos enthaltenen Mengen an Vitamin A sind im Allgemeinen niedriger, aber die aus diesen Studien gezogenen Schlussfolgerungen reichen, um bei diesem Inhaltsstoff Vorsicht walten zu lassen – zumindest im ersten Schwangerschaftstrimester.


Sodiumlaurethsulfate (SLES), was nicht dasselbe ist wie Natriumlaurylsulfate, sind Inhaltsstoffe zur Schaumbildung, die bei Seifen und Shampoos verwendet werden und mit Krebserkrankungen und einigen angeborenen Fehlbildungen in Verbindung gebracht wurden. Lesen Sie, was auf der Packung steht, und vergewissern Sie sich, dass Sie einen Hinweis „frei von SLES“ darauf finden.

Methylisothiazolinon (MIT)

Methylisothiazolinon (MIT) ist ein Inhaltsstoff, der zur Abtötung schädlicher Bakterien eingesetzt wird, die anderenfalls in der Feuchtigkeit von Shampoos und Lotionen besonders gut gedeihen würden. Dieser Wirkstoff hat schon in den frühen 2000ern Bedenken aufkommen lassen, als eine wissenschaftliche Studie zeigte, dass MIT die Fähigkeit unserer Zellen stören kann, untereinander zu kommunizieren.

Die Studie zeigte, dass eine längere Exposition gegenüber selbst kleinen Mengen der Chemikalie die Entwicklung von Strukturen der Nervenzellen beschädigt, genauer gesagt Zellfortsätze (Dendriten) und das Axon. Diese spielen eine wichtige Rolle bei der Signalübertragung zwischen Nervenzellen. Die ursprünglichen Tests wurden an Ratten durchgeführt, allerdings äußerten die Wissenschaftler die Befürchtung, dass die Auswirkungen von MIT bei ungeborenen Babys ähnlich sein könnten.

Inhaltsstoffe, die Sie auf der Verpackung sehen wollen

Glücklicherweise gibt es eine ganze Reihe von natürlichen Shampoos und Pflegespülungen, die die genannten schädlichen Inhaltsstoffe vermeiden und Ihnen während der Schwangerschaft dennoch zu gesundem, glänzendem Haar verhelfen. Beim Aussuchen der Produkte sollte Sie nach einigen Inhaltsstoffen Ausschau halten, die besonders hilfreich sind. Dazu gehört Sheabutter, die dem Haar dabei hilft, Feuchtigkeit zu speichern und dadurch vor Haarbruch schützt. Ähnlich verhält es sich mit Kokosöl, das dabei hilft, ihre Haarfollikel mit Feuchtigkeit und Vitalität zu versorgen.

Ein anderes Wundermittel ist natürlich Aloe vera, die dabei helfen kann, Haarausfall zu vermeiden, indem sie Ihrem Haar essentielle Aminosäuren liefert und damit auch für gesunden Glanz sorgt.


Die Schwangerschaft ist wirklich schon stressig genug, auch ohne Zeit damit zu verbringen, die Angaben auf Shampoopackungen nach schädlichen Chemikalien zu durchsuchen. Wenn Sie stattdessen pflanzliche Alternativen wählen, können Sie sich das alles einfach sparen und haben eine Sorge weniger.

What are the most potentially harmful ingredients in conventional shampoo?

The marriage between modern science and commerce has produced some beautiful children over the years. For example, space rockets, segways and Michael Jackson. But of course science and capitalism have also produced some weird children too. That’s right, we’re looking at you, cosmetics industry.

Over the last 100 years or so big companies have enlisted the help of the best geeks to produce products that make our lips more luscious, the angle of our cheekbones more acute, and of course our hair more vibrant. Because these scientists have also been instructed to keep costs low, eventually society has ended up with a whole bunch of chemicals that may do all of the above, but at considerable risk to our health. In other words: while they were focusing on the cosmetic aspects, some health concerns may have fallen by the wayside. Below is a brief overview of two of the most worrying ingredients found in your shampoo.

Sulfate self-hate

Sulfates are a frothing ingredient found in many cosmetics and cleaning materials. They will usually be listed as SLS (sodium lauryl sulfate), sodium laureth sulfate (SLES), or ammonium laureth sulfate (ALS) — all words worth at least 35 points in scrabble. Basically, they are used to dislodge dirt and oil from your hair.

SLS and ALS are both considered anionic surfactants but are quite different in their molecular structures. ALS is much larger which means that it’s less likely to penetrate your pores. SLS, on the other hand, is the chemical that often gets written about because it is small enough to literally get under your skin and possibly cause irritation, reddening and erythema of the epidermis.

In America the U.S. Food and Drug Administration has required that manufacturers carry a warning label about the dangers of swallowing too much toothpaste (which contains SLS) because of the risk of diarrhea. Also, some studies have shown that SLS has been linked to irritation of the skin and eyes, organ toxicity, developmental/reproductive toxicity, neurotoxicity, endocrine disruption, ecotoxicology, and biochemical or cellular changes.

To be fair, when it comes to toxicity you have to keep dosage and exposure in mind. After all, high concentrations of cinnamon oil would be toxic on your skin. A shampoo containing 15 percent SLS can be sold to the public because it generally comes into contact with your skin for just a few minutes and is diluted by water. Still, these levels are broadly determined with the average person in mind. The fact that you’re reading this probably means that you have had some kind of negative reactions on your skin as a result of using conventional products, which means you have reason to be more cautious than most.

Parabens bans

Parabens belong to the family of esters of para-hydroxybenzoic acid. There are all sorts of technical names for the various kinds, such as methylparaben (E218), ethylparaben (E214), propylparaben (E216) and butylparaben, which are the most common. They are antibacterial and antifungal agents, which is why they are used as preservatives. They can even be found naturally in food such as strawberries or peaches, as well as in the human body.

Like sulphates the toxicity of industrially produced parabens depends on the degree to which you are exposed to them. Though each product typically stays within government stipulated limits, it becomes harder to track the cumulative effect of these products given that they are found in so many products. In other words: Using one manufacturer’s products won’t be very problematic. Using many different ones over a lifetime could start to add up.

Parabens are worrying because they tend to disrupt hormone function, an effect which some have linked to breast cancer and reproductive toxicity, according to the NGO Campaign for Safe Cosmetics (CSC). Parabens function as estrogen mimics. That means your body perceives an increase of estrogen levels which is said to trigger a more rapid division of breast cells. It must be said that new research suggests that the link between parabens and cancer is inconclusive. But this is not just a matter scientific “he said, she said”. At the end of the day, the risk parabens pose is so severe that in 2014 the EU banned five specific parabens from being used commercially.

Bottom line

There probably isn’t a mass conspiracy to give you cancer through your shampoo. Regulators are very careful about the concentration of chemicals that they allow you to get exposed to. At the same time, specifically sulphates and parabens have made their way into so much of our everyday products that the cumulative effect is beginning to be problem — especially when it comes to a product that some literally use every day. Fortunately there are a number of natural alternatives that clean you well without incurring unnecessary risks.

So what are the safe alternatives? Well yes, this is the part where we make a shameless promotion of our products because they are safe, natural alternatives. Have a read about them here, or first read on about the wonders of natural alternatives.