Soap-based Solid Shampoo Bars Versus Syndet Shampoo Bars: What’s the Difference?

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Did you know that there are two different types of shampoo bars? Cold or hot process soap-based ones, which are all natural, and syndet bars, which are normal shampoo and conditioner in bar form.

Soap-based solid shampoo bars and syndet solid shampoo bars have different ingredients, work differently on your hair and need different rinses/conditioners. We explain the difference below and share some of our favourite solid shampoos from each camp and which one you should go for depending on your hair type and condition.

Like liquid shampoo, it can take a while to find the right one for you and your hair type. If one type or brand doesn’t work for you, it is worth trying the other or another brand; however, there are some ingredients you should avoid, so investigate what’s in a bar before you start experimenting with it. You’ll find what our research on some popular and local Australian brands revealed below.

Soap-Based Solid Shampoo Bars

Soap-based solid shampoo bars are made from all-natural ingredients and essential oils. To make these shampoo bars, either a hot or cold soap-making process is used.

The difference between these two methods involves the use of external heat, the time it takes to saponify, the curing time, and the finish of the soap. For the cold process, no additional heat is used to facilitate the saponification process and it takes longer. Cure time is also longer and the soap has a smooth finish. While, for the hot process, an external heat source is used and saponification and curing is quicker. The end product is more textured and rustic.

Importantly, your hair needs to adjust to these bars as they are different to the normal liquid shampoo your hair is used to, so there will be an adjustment phase while your hair gets used to them.

Aoraki Naturals notes: “When beginning to use soap as a shampoo it can take time for your hair to adjust due to residual chemicals from commercial shampoos. This transition phase can take anywhere from one to eight weeks as your hair adjusts and the natural oils balance out. It is normal to experience lank, heavy, slightly greasy hair at first.

“This WILL pass! Using an acidic rinse of 1T of apple cider vinegar (or white vinegar)  to 1c of warm water after washing can help. Personally, it took about a month until my hair felt normal again … but now I don’t even need a conditioner and my hair is soft and shiny. Again, results will vary from person to person.”

These shampoo bars are more alkaline so it is a good idea to use an acidic rinse with them; however, generally, no conditioner is needed when using soap-based bars.

These bars generally work really well if you have dandruff, as they don’t contain sulphates and silicone, which can irritate and dry out the scalp. In addition, apparently coconut-based soap is more drying but makes a better lather, while olive oil-based soap is less drying but doesn’t lather.

These types of bars are generally cheaper than syndet bars as the ingredients used to make these bars are cheaper to buy.

Every maker has a different recipe so finding the right bar for you can be a process of trial and error. Australian brands that make this type of shampoo bar that are worth checking out are:

  • Australian Natural Soap Company - all natural, vegan, palm oil free, sulfate free, paraben free, and detergent free and handmade in Melbourne with ingredients sourced from within Australia. They have an original solid shampoo, one for sensitive scalps, one for dry hair and one for oily hair, as well as a dog shampoo bar!

  • Aoraki Naturals - 100% natural solid shampoo that is hand-crafted in New Zealand in small batches; no palm oil, animal fats, synthetic fragrances or colourants are used.

  • Dirty Hippie Cosmetics - “sneaky SLS and nasty chemical silicone”-free soothing hair growth shampoo bars developed for itchy scalps, dreadlocks and most hair types that is handmade to order. It also sells natural dry shampoo powders (one for light hair and one for dark hair) in compostable packaging!

  • Quintessence Soaps - only natural ingredients and traditional processes are used for these solid shampoo and conditioner bars. They do not contain animal fats or recycled oils, preservatives nor the petrochemical derivatives propylene glycol (emollient), sodium lauryl sulphates (detergent/foaming agent) or Sorbolene. In addition, FDA Food Colours or Fragrance Oils, which are both synthetic, are not used.

  • Beauty and the Bees - hand made using only natural healthy ingredients like honey, egg, beer, charcoal, and/or herbal infusions. No synthetic ingredients! They have a couple of different formulations for different individual requirements that are based on hundreds of years of traditional use.

  • Modern Day Earth Mumma - sells an anti-poo movement pack containing a poo bar, a conditioning rinse, and a hair masque, as well as a hair detangler/leave in conditioner. Products contain no preservatives and no parabens and are vegan friendly and herbal tea based.

  • Cedar + Stone - plastic-free head lice prevention and treatment! Gentle, vegan, palm oil free and with no parabens, SLS's or harsh chemicals, its head lice shampoo bar can be used to prevent and treat head lice.

  • Urthly Organics - hair and body shampoo that never contains SLS, SLES, parabens, fluoride, titanium dioxide, glycols, fragrance oil or mineral oils and is 100% palm oil and palm derivative free. Using mostly organic products, ingredients are acquired straight from the grower where possible and are produced in a sustainable environment.

  • Dindi Naturals - a natural, plant-based, cruelty free, vegan-friendly shampoo travel soap that doubles as a body soap and provides a nourishing, gentle all-over wash. It doesn’t contain silicone, palm oil or nasty chemicals. It can be used on its own for a quick and easy shampoo (excellent for short hair), but combining it with a liquid conditioner is recommended for best results. The company’s solid conditioner bars give extra shine and moisture.

Other local Australian small business brands that I have seen recommended are Robyn Soap House, The Hazelnut Tree, Barany Naturals, Windella Farm, and Nude Nourishment.

For those in the US/Cananda, Well.ca has a range of natural shampoo bars, including meow meow tweet’s shampoo bar and Rocky Mountain Soap Co.’s shampoo bar and Life Without Plastic stocks Chagrin Valley’s Conditioning Shampoo Butter Bar.

Syndet Solid Shampoo Bars

Syndet solid shampoo bars are a synthetic detergent. They are not completely natural as surfactants used and they are generally the same as and contain the same ingredients as the liquid shampoo your hair is used to, just without the water content.

You get gentle surfactants like sodium lauryl sulfoacetate and harsh ones like sodium lauryl sulfate, with some brands using gentle surfactants and some using harsh ones.

Sodium lauryl sulfate has been linked to cancer, neurotoxicity, organ toxicity, and endocrine disruption, but these links have not been proven. It also has a potentially toxic effect on aquatic organisms. Consumer advocacy groups such as the Environmental Working Group advise using SLS-containing products with caution.

Some people’s scalps are sensitive to these strong surfactants, which dry and irritate the scalp, so if you choose to use syndet bars, we recommend finding a brand that uses a gentle surfactant and avoiding brands such as Lush that use potentially toxic SLS.

As they have the same ingredients and work the same as commercial liquid shampoo, you will not have to go through a transition period.

They have a lower pH and you will probably still need to use a conditioner with this type of shampoo bar.

The ingredients to make syndet bars are more expensive, so these shampoo bars are generally more expensive than the soap-based ones.

Some brands that make and sell syndet bars are:

  • Lush - the surfactant used by Lush is sodium lauryl sulfate. It creates a rich foam and leaves an unbeatable feeling of cleanliness, but it is an unnecessarily harsh surfactant. It also uses synthetic colours and the fragrances used are made up of approximately 60% natural oils, resins and absolutes. Some formulas are 100% natural and some are less so. In addition, there are still traces of palm derivatives in some of its safe synthetics range. The company notes that “a complete transparency of and removal of palm oil is in progress”.

  • Ethique - certified cruelty-free and vegan, palm oil free and made in a factory powered by 100% renewable energy, these solid shampoo bars are equivalent to up to three bottles of liquid shampoo, 100% soap free, pH balanced, and safe for colour treated hair. It combines natural ingredients with a knowledge of science to create soaps that are effective, gentle, and better for the environment. Sodium coco-sulfate, which is a milder, safer synthetic detergent than SLS, is used. It has a more complex molecular structure and this prevents it from penetrating the epidermis, meaning it has less irritancy as it cannot reach the living cells under the skin surface. The company also makes conditioner bars and hair masks that boost the condition and shine of your hair, as well as a shampoo bar for babies and kids.

  • Creative Aromas NZ - these shampoo bars are made using a range of gentle surfactants to maintain a neutral ph, with the company noting that this ensures it doesn’t strip the hair like some shampoo bars can. Its shampoo and conditioner bars can last up to 80 washes and are full of nourishing oils, butters and proteins. Its different blends are suited to different hair types - normal, fine, oily, dry, curly, and sensitive scalps.

  • Stone Rose Soaps - a family business based in Auckland, the ingredients are sourced from other Kiwi businesses and carefully selected, with every ingredient chosen for use in products being well researched and tested. The surfactant used in its shampoo bars is sodium lauryl sulfoacetate not sodium lauryl sulfate; its molecules are too large to penetrate the skin; therefore it causes less irritation than sulfates, but it can still be an irritant according to some sources. It is a mild cleansing, a non soap formula is used and it is panthenol infused and hydrosol infused. Its conditioner bars are non greasy, silicone free, palm free, panthenol infused and cruelty free. Unlike other conditioner bars, which contain mostly butters and oils, they contain emulsifying and conditioning ingredients for silky tangle free hair.

Ethique’s shampoo and conditioner bars are very popular, as are Lush’s. Most people are aware that Lush uses a lot of chemicals in its bars and some avoid the brand because of this. However, the company’s bars do work well for some people who have struggled with using natural shampoo bars and who have hair that needs something stronger than a completely natural bar or whose hair just does not feel clean using these bars. It is a good zero waste option for many.

Ethique is more natural and less harsh than Lush, and it also has better company ethics, but its bars still contain surfactants; they are gentle however, so it seems to be a good middle ground between completely natural and potentially toxic. The same goes for Creative Aromas NZ and Stone Rose Soaps.

Ethique has different bars for different hair types so it is easier to figure out which one might work for you:

Trial and Error Time

It may take a few bars to figure out what is right for you and your hair, so if the first bar you try doesn’t leave you and your hair feeling clean, maybe try a different type of bar or a different brand - don’t give up on shampoo bars just yet!

Try and figure out why the bar you are using isn’t for you - have you given it enough time to allow your hair to transition, look at the ingredients, read reviews, and ask other zero wasters if anyone has had the same issues - they may have the answer to the right bar for your hair type.

You can even get sample sizes and tester packs so you can test them out without having to commit to a whole bar, which lasts ages.

Beauty and the Bees has a shampoo sampler box that contains six sample-sized shampoo bars so you can try the various shampoo varieties to find the ones best suited for your hair and scalp. It also sells a healthy hair starter pack that includes the shampoo, conditioner and rinse you need for your new natural hair care routine.

Ethique’s hair sampler contains five heart-shaped bar samples of the top sellers from the company’s hair care range. They are generously sized so you can truly test each one out, with each bar providing weeks of use so you can fully suss out the effectiveness of every product.

It is also worth checking if a bar is palm oil free or uses sustainably sourced palm oil, as not all of them are palm oil free.

We are lucky to now have so many different shampoo bars and so much choice when it comes to making our hair routine zero waste.

If you prefer liquid shampoo to a bar, you can find liquid shampoo and conditioner at most bulk food stores. You can also get natural dry shampoo in compostable packaging from Dirty Hippie Cosmetics (AU) and Black Chicken Remedies (AU) and Captain Blankenship’s dry shampoo (US/CAN) comes in a cardboard shaker tube.

And some people can get away with just washing with bicarb soda mixed with water and then rinsing with apple cider vinegar mixed with water, while others go the no poo route and simply wash with water every couple of days (massage your scalp as the water runs over it).

Get out of your hair comfort zone and get experimenting with zero waste haircare!

Happy experimenting! Let us know how you go!

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