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Soap vs Syndet Shampoo Bars

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Soap vs Syndet Shampoo Bars


For several years now, we’ve been making soap-based shampoo bars using the same cold process soap making methods that we use to make our face and body soaps. Based on customer feedback and our own research, we’ve recently decided to start making detergent based or “syndet" shampoo bars, as well.

While both are designed to accomplish the same thing (wash your hair), soap-based shampoo bars and syndet shampoo bars are each made from different ingredients, work differently on your hair, need different rinses/conditioners, and have pros and cons (all of which we will discuss in this article).

Benefits of Using a Solid Shampoo and Conditioner Bar

Before we break down the differences and similarities between soap-based and detergent-based shampoo and conditioner bars, let’s take a quick look at their advantages over liquid shampoos/conditioners.

First, plastic pollution is one of the most serious global environmental problems that we currently face, and we must overcome our addiction to plastic packaging. Our oceans, rivers, landfills, and roadsides are strewn with waste that won’t break down in any meaningful amount of time. Shampoo bars are one easy way to get plastic out of our everyday routines and to reduce our dependence on this polluting, toxic product.

Secondly, most liquid shampoos are 70% to 80% water. Shampoo bars are a fraction of the weight of bottled shampoo, so fewer trucks are needed and less oil is used to transport them, and they take up less shelf space. Shampoo bars are usually packaged in paper boxes rather than plastic. This means much less energy and oil are used in making the packaging. When you’re done with the package, you can just compost it rather than sending it to a landfill where it will take millennia to decompose.

Third, solid shampoo bars save lots of room in your suitcase and toiletry bag. Do you like to travel fast & light? TSA-friendly shampoo bars will help you get through check-in without the hassle of liquids. In fact, some people buy them just for travel but then find they like them so much they switch to using them all the time.

Finally, because shampoo bars don’t contain water, they are concentrated and you only need to use a small amount per wash. A 3-4 ounce shampoo bar often lasts for about 40 to 60 washes, depending on the length of your hair. This is about as long as a 20-oz bottle of liquid shampoo, making them a much better value.

What Is Soap Based Shampoo?

Soap-based shampoo bars have been around for a long time. Before the development of detergent based liquid shampoo in the 1940s and 1950s, people often used soap as shampoo. Today, soap-based shampoo bars are made in the same way as any other bar soaps. The main difference is that the soap makers usually add specific ingredients during the soap-making process that are designed to cleanse and nourish your hair and scalp. Both soap and soap-based shampoo bars are made from a combination of oils mixed with sodium hydroxide (lye) and go through a chemical process known as saponification which creates the final product.

What Are the Pros of Using a Soap Based Shampoo?

Soap Based Shampoo Bars Are Made with Natural Ingredients

The biggest benefit of using soap-based solid shampoo bars is that, unlike liquid shampoo or syndet shampoo bars (which are made from laboratory derived surfactants), they are made directly from natural ingredients such as vegetable oils and butters, clays, plant extracts, and essential oils.

Soap Based Shampoo Bars Don’t Require Using a Conditioner

Generally, no conditioner is needed when using soap-based shampoo bars. These bars generally work really well if you have dandruff as they don’t contain sulphates and silicone (like liquid shampoos and some syndet shampoo bars), which can further irritate your scalp and dry out your hair.

Soap Based Shampoo Bars Are Less Expensive

Finally, soap-based shampoo bars are generally cheaper to buy than syndet bars, as the ingredients used to make these bars are less expensive for manufacturers to purchase.

What Are the Cons of Using a Soap Based Shampoo?

Soap Based Shampoo Bars Have A High pH

The main problem with using soap as shampoo is that it is alkaline and has a pH of 9-10, while your hair and scalp itself is slightly acidic with a pH of 4.5-5.5. So, you usually have to regularly treat your hair and scalp with something acidic like an apple cider vinegar rinse to get it back to the proper pH.

Soap Based Shampoo Bars Require an Adjustment Period

Secondly, as your hair gets used to soap-based shampoo bars there may be an adjustment period and your hair may look oily and feel waxy as the soap makes the hair shaft swell and the cuticle scales open, which can lead to dry frizzy hair and cause damage to the follicles. This may last from a few washes to several months or more, and many people give up in the process and switch back to normal shampoo before the adjustment is complete.

Soap Based Shampoo Bars Don’t Work Well with Hard Water

Finally, for people on wells or those who have hard water, calcium and magnesium often reacts with soap-based shampoos, leaving a permanent residue or build-up on your hair and scalp, which may never go away (even after an adjustment period) and usually requires the installation of a water softener to get rid of.

What Is a Syndet Based Shampoo?

Syndet shampoo bars are a non-soap-based detergent cleanser made from surfactants, like the ones found in liquid shampoos. “Syndet” is short for synthetic detergent, because the surfactants are produced “synthetically” in a laboratory by combining plant oils with water-loving molecules such as ammonium or sulphate ions. As a result, syndet shampoo bars generally contain similar ingredients to liquid shampoos, just without the water content.

High quality, eco-friendly ones also contain specific ingredients (such as conditioners, and moisturizers, vegetable oils, vitamins, minerals, antioxidants, botanical extracts, and essential oils) that are designed to cleanse and nourish your hair and scalp in addition to cleaning it.

What Are the Benefits of Using a Syndet Shampoo?

Syndet Shampoo Bars Have a Low pH

The biggest advantage of using a syndet shampoo bars is that they have a lower pH than soap-based shampoos. Ideally, hair care products should be between about pH 4.5 and 6 to help maintain hair’s softness and manageability and to protect it from breakage. Unlike soap-based shampoos, the pH of syndet shampoo bars can be easily adjusted during production by using different surfactants and adding small amounts of citric acid. We have formulated our syndet bars to have a pH between 4.5 and 5.5.

Syndet Shampoo Bars Don’t Require an Adjustment Period

Secondly, because they contain similar ingredients and work in the same manner as commercial liquid shampoo, you will not have to go through an adjustment period with syndet shampoo bars that you have to with soap-based shampoo bars. Furthermore, because the surfactants used in syndet bars don’t react with the minerals in hard water, they won’t leave residue or build up on your hair and scalp.

What Are the Cons of Using a Syndet Shampoo?

Syndet Shampoo Isn’t Considered as Natural as Soap Based Shampoo

Because the surfactants in syndet shampoo and conditioner bars are laboratory derived from vegetable oils using a chemical process, rather than created directly from oils themselves during the soap-making process, they are not considered to be as natural as soap-based shampoos.

Some Syndet Shampoo Bars Contain Potentially Dangerous Surfactants

The quality and eco-friendliness of a syndet shampoo bar has a lot to do with the mixture of surfactants it contains. Some are gentler and more natural than others. Sodium Lauryl Sulfate (SLS) and Sodium Coco Sulfate (SCS) and other sulfates are often added to commercial liquid shampoos and some shampoo bars to increase lather quality. If you’ve tried other shampoo bars and they dried your hair out or caused irritation or rashes, they may have been made from SLS or SCS, which are potentially dangerous surfactants.

SLS and SCS have been linked to cancer, neurotoxicity, organ toxicity, and endocrine disruption. They are also believed to be harmful to aquatic life. Consumer advocacy groups such as the Environmental Working Group advise against using products containing SLS and SCS. If you choose to use syndet bars, we recommend finding a brand that uses gentle surfactants and avoiding brands that use SLS or SCS.

Some Syndet Shampoo Bars Contain Silicone

Like their liquid counterparts, some syndet shampoo bars contain synthetic silicones (such as dimethicone, dimethiconol, and phenyl trimethicone) which are added to smooth hair follicles and prevent frizziness. The problem is that over time, silicones can build up on the hair, weighing it down and leaving it looking dull and lifeless. As a result, we suggest finding a brand that doesn’t use silicones in their shampoo bars.

Syndet Shampoo Bars Require Using a Conditioner

Because they have a lower pH, you will probably still need to use a conditioner with syndet shampoo bars.

Syndet Shampoo Bars Are More Expensive

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

Syndet Shampoo and Conditioner Ingredients

Our syndet shampoo and conditioner bars are designed for all types of hair and are a gentle, all-natural, environmentally-friendly alternative to chemical-laden liquid shampoo and conditioner.

Safe for bleached and color treated hair, these bars contain a blend of plant-based surfactants, conditioners, and moisturizers, vegetable oils, vitamins, minerals, antioxidants, botanical extracts, and essential oils. These ingredients will gently cleanse your hair and scalp, repair and strengthen it, promote new growth, enhance body, seal in moisture, and make your hair feel soft, silky, and manageable.

We use a mixture of high-quality, eco-friendly ingredients in every shampoo and conditioner bars to increase mildness and to make the formulas appropriate for different hair types, whether dry, normal, oily, or thinning.

Each bar contains a combination of the following ingredients:

Sodium Cocoyl Isethionate (SCI) is a naturally derived surfactant made from coconut oil. It is safe and non-toxic and is one of the mildest cleansers available. It is frequently found in baby products because it is extremely gentle on sensitive, delicate skin and hair. SCI acts as a foaming and cleansing ingredient, and leaves your hair feeling soft and silky.

Sodium Lauryl Sulfoacetate (SLSA), not to be confused with Sodium Lauryl Sulfate (SLS), is derived from coconut or palm oil and is a safe, skin friendly cleanser that provides a high-quality lather which gently and effectively removes surface oil, dirt, and bacteria, without stripping or drying out your hair.

BTMS-25 (Behentrimonium Methosulfate and Cetearyl Alcohol) is a plant-based emulsifier and conditioning agent. It is derived from rapeseed and coconut oils.

Cetyl Alcohol is made up of fatty acids derived from coconut oil and provides softening and hydrating properties to your hair and acts as a thickener.

Panthenol (Provitamin B5) protects hair from styling and environmental damage by locking in moisture and improving its strength and structure. It also adds volume, shine, and luster.

Hydrolyzed Oat Protein is a liquid cosmetic ingredient made from oat protein that has been modified to be water-soluble. It contains two types of proteins - globulins and avenin, both of which are not found in any other grain. Hair products that contain hydrolyzed oats are known to make your hair shiny, reduce breakage, soften and smooth, and repair and protect your hair from damage. Hydrolyzed oat flour protein also forms a coating on the outside layers of hair strands, which can make it look and feel thicker.

Vegetable Glycerin is derived from plant oils. Glycerin is a humectant, meaning it can actually pull in moisture from the air, keeping hair hydrated and healthy.

Honeyquat is a naturally derived conditioning agent made from honey. It is an excellent moisturizer, and is able to penetrate hair strands to provide its moisturizing benefits while also adding shine and luster. Honeyquat also reduces static buildup and improves comb-ability of wet and dry hair. We make shampoo and conditioner formulas both with and without honeyquat to provide vegan and non-vegan options to our customers.

Citric Acid is derived from lemons. In addition to naturally lowering the pH in shampoos and conditioners, it also helps remove buildup from your hair and adds shine. The esters formed from Citric Acid create a thin protective coating over the surface of your hair which prevents the loss of moisture from the strands making it look glossy and hydrated.

Kokum Butter is derived from the seeds of the Kokum Tree, and is a firm, mildly scented butter, with a variety of benefits for the hair and scalp. It is rich in essential fatty acids and non-comedogenic, perfect for stimulating the scalp to create healthy hair growth. Kokum helps cell oxygenation, making nutrients more readily available for use by scalp/skin tissues. It also supports and enhances hair elasticity, helping to prevent breakage.

Shea Butter is made from the nuts of Karite tree from West Africa. It is packed with various fatty acids, vitamins A and E, calcium, sodium, iron, magnesium, and zinc, that can seal in moisture, soften hair for easy styling, reduce dryness, prevent split ends, increase shine, and lessen frizz. Moreover, Shea Butter contains triterpenes that trigger collagen production and promote hair growth and antioxidants to protect hair, while its anti-inflammatory properties treat dry, flaky, irritated scalp and reduce dandruff.

Jojoba Oil is very similar to sebum, your skin’s natural oil. This natural moisturizer helps protect the scalp from irritation, conditions hair, moisturizes, fights bacteria, strengthens the hair shaft, thickens strands, and repairs damaged hair.

Argan Oil is mostly used as a moisturizer in hair care because it is full of fatty acids, mainly oleic and linoleic acid. These oils have been shown to lubricate the hair shaft and help your hair maintain moisture. Argan oil also has anti-inflammatory and antioxidant properties that can help prevent or improve scalp conditions that can cause hair loss, like psoriasis and seborrheic dermatitis.

Avocado Oil is a non-greasy oil that is incredibly rich in vitamin E, amino acids, minerals, lecithin and potassium, and has a high content of polyunsaturated and monounsaturated fats, to moisturize your hair and add shine, strengthen strands, add vibrancy, and increase elasticity.

Aloe Vera Powder has many active ingredients and minerals that can help strengthen your hair, including fatty and amino acids and is rich in vitamins A, B12, C, and E. These play a part in creating healthy hair follicles. Aloe vera has enzymes that strips your hair of extra oil. It also helps treat dermatitis by eliminating dandruff and reducing itchiness.

Hibiscus Flower Powder is rich in amino acids which aid in the production of keratin and stimulate hair growth, thicken hair and add volume. Traditionally, Hibiscus was used as a natural dye to mask grey hair. The antioxidants and vitamins present in Hibiscus not only increase shine and luster, but they help in producing melanin, the naturally occurring pigment that gives hair its natural color and prevents greying.

Horsetail Extract is derived from the Horsetail plant, a member of the fern family. Horsetail is known to improve blood circulation in your scalp and stimulate the hair follicles. The silica in horsetail has been shown to encourage hair growth, aid in collagen production, and improve the overall look and feel of your hair.

Nettle Leaf Powder is high in antioxidants, vitamins A, C, and K and minerals such as calcium, magnesium, iron, and phosphorous. Its leaves are rich in silica and sulphur, and they have anti-inflammatory properties. Nettle has been used for centuries to improve the shine and appearance of hair, as well as combat hair loss and promote new growth.

Calendula Powder is often used to hydrate the scalp, remove dandruff, and treat various conditions. With its regenerative properties it helps the hair follicles grow abundantly allowing for a thicker mane, and the antioxidants help protect the hair and scalp against cell-damaging free radicals.

Chamomile Powder contains antioxidants that act as a natural exfoliator, removing dead skin cells and product build-up that has collected on the scalp. In turn, this reduces itchiness, dryness, and bacteria that thrive on the scalp, significantly reducing common scalp complaints such as dandruff.

Gingseng Extract is believed to increase the growth of dermal cells on the scalp which, in turn, strengthens the follicles and roots of the hair. Additionally, the chemical compound ginsenoside found in ginseng helps to nourish the roots, encourage new hair growth, and lessen thinning hair and breakage.

Turmeric Powder has many anti-inflammatory properties that help stimulate growth and prevent hair loss. Its antibacterial components prevent irritation, itchiness, and dandruff, help keep the scalp healthy, balance oil production, and fight dandruff.

Willow Bark Extract contains salicylates (salicylic acid) that act as a gentle exfoliant. The exfoliating properties of Willow Bark mean it is essential for cleaning the hair and scalp, eliminating dandruff, removing dirt and product build-up, and getting rid of dead skin cells. Willow Bark in hair products also helps control excess sebum, and leaves hair strands looking healthy.

Burdock Root Extract contains all the necessary amino acids for building the protein keratin that creates hair. It also contains vitamins and minerals A, C, D, iron, and folic acid, which can help stop hair loss, nourish the scalp, and strengthen hair.

Rosemary Extract has antioxidant and anti-inflammatory properties that can help reduce dandruff, and dry itchy scalp, and prevent premature graying. The carnosic acid in rosemary has been found to also dilate blood vessels, improve circulation in the scalp and preventing hair follicles from being starved of blood, dying off, and leading to hair loss.

How to Use Shampoo and Conditioner Bars

Shampoo and conditioner bars are extremely easy to use. Simply rub the bar directly on your wet hair to create a lather, gently massage into your hair and scalp, and rinse thoroughly. For conditioner bars, let the lather sit in your hair for at least 3 minutes before rinsing. Ensure the shampoo and conditioner bars dry completely after each use to extend their shelf life.


Like liquid shampoos, it can take a while to find the right shampoo bars for you and your hair type. Our Tea Tree Lemon Hair Soap continues to be a customer favorite. If a soap-based shampoo bar doesn’t work for you, it is worth trying a syndet based shampoo bar. However, as we discussed above there are some ingredients you should avoid, so make sure to investigate what’s in each bar before you start experimenting with it. We make several options of several options of syndet Shampoo and Conditioner Bars to suit a variety of hair types.

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