Choosing the right method to take care of your hygiene and skin health can raise many questions, especially with so many new products entering the market daily. In order to avoid using harsh chemicals, many people are choosing natural products like syndet bars and hoping to achieve the same hygiene standards and potentially even better skin health than with regular soaps. Why choose a syndet? What makes it so popular and beneficial? Read the following article as we go through some medical research about dermatological soap bars and learn if this is the right choice for you.
Why Choose a Syndet?
Summary
Published on February 9, 2025, updated on February 11, 2025, by Andjela, Chemical Engineer — 6 min of reading
Themes:
Advantage #1: Syndets Provide Gentle Cleansing with Mild Surfactants.
The most important synthetic detergents are alkyl sulfates and their derivatives, commonly marketed as "sulfates." Sodium lauryl sulfate (SLS), which is arguably the most important member of this group, is made of lauryl alcohol and sulfur trioxide. Due to their potential for irritation, they have fallen out of favor in most uses apart from some organic shampoos. Alkyl ether sulfates are now favored instead, made by ethoxylated alkyl sulfates. Ethoxylation reduces irritation but does not eliminate it completely, and it is not supported in organic-certified products.
Contemporary formulations for soap-free cleansers, syndets, and dermatological soap bars are increasingly based on isethionates and sarcosinates. Sodium cocoyl isethionate, obtained from coconut oil, is widely incorporated into the formulations for syndet bars and solid shampoos, while N-acetyl sarcosinates, derived from the combination of sarcosine and fatty acids, are commonly found in shampoos and shower products.
Chemical structure of Sodium Carboxylate (Soap).
Source: COUTEAU C. & al. Soap and syndets: Differences and analogies, sources of great confusion. European Review for Medical & Pharmacological Sciences (2020).
Chemical structure of an alkyl sulfate.
R = hydrocarbon chain including 12 to 18 carbon atoms; X = Na, K or NH4. Source: COUTEAU C. & al. Soap and syndets: Differences and analogies, sources of great confusion. European Review for Medical & Pharmacological Sciences (2020).
Chemical structure of sodium lauryl sulfate.
Source: COUTEAU C. & al. Soap and syndets: Differences and analogies, sources of great confusion. European Review for Medical & Pharmacological Sciences (2020).
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Synthetic detergents, being anionic surfactants, display amphiphilic characteristics and greatly resemble traditional soaps. Their functions as surfactants include wetting agents, emulsifying agents, detergents, and foaming agents. All these make them very versatile and essential ingredients in modern cleansing products for all body parts - including face, scalp or intimate area.
The results of a 28-day study indicate a significant benefit for atopic dermatitis (AD) in 50 patients who used a syndet cleansing bar, instead of soap, which was previously used by 70% of the participants. Syndet application reduced the severity of eczematous lesions, erythema, pruritus, tightness, irritation, and dryness (P ≤ 0.5) while improving skin smoothness, softness, and appearance. These findings underscore that syndet formulations are beneficial in retaining moisture and minimizing disturbances to the stratum corneum in AD patients.
Advantage #2: Syndets have a physiological pH that respects the skin.
Another important benefit to mention is that syndets have a natural or slightly acidic pH, ranging from 5.5 to 7, which is relatively close to the skin’s physiological pH (4.5 - 5.5). In conclusion, these products support the skin barrier and don’t irritate the skin or strip its natural oils like alkaline soap with a higher pH.
Advantages #3: Syndets are suitable for all skin types.
Cleansing is important for everyone, but people with specific skin conditions must choose the right product for their personal needs, because it can make the vital difference between aggravating or alleviating symptoms. Studies have shown that syndet bars are milder than traditional bars on the skin and are ideal for skin conditions such as atopic dermatitis, eczema, acne, and rosacea. While not everyone may need to use a syndet bar, those using harsh soaps would benefit from switching to a milder syndet cleanser.
It was proven that syndet bars ensure optimal skin hygiene while reducing damage to the skin barrier. While soap based cleansers cause barrier disruption, lipid dissolution and pH alteration, a study by MEYER F. (2004) confirmed that syndets containing emollients minimize skin barrier damage in two primary ways: by restricting the interaction of cleanser surfactants and skin proteins and lipids, and by replacing those that are inevitably lost during washing.
Sources
PAYE M. & al. A comparative study of the effects on the skin of a traditional bar soap and a syndet cleansing bar under normal usage conditions and in the soap chamber test. Skin Research and Technology (2001).
MEYER. F. & al. Uncompromising cleansing: the impact of cleansers on the skin barrier and gentle cleansing technology. Dermatological Therapy (2004).
GOTTLIEB A. & al. Benefits of gentle cleansing: synthetic surfactant bars (syndet) for patients with atopic dermatitis. Cutis (2006).
KORTING H. C. & et al. The pH of the skin surface and its impact on the barrier function. Pharmacology and Physiology of the Skin (2006).
NOLE G. & et al. Cleansing bars. Cosmetic Dermatology: Products and Procedures (2015).
DRAELOS Z. D. The science behind skincare: cleansers. Cosmetic Dermatology Journal (2018).
COUTEAU C. & al. Soap and syndets: Differences and similarities, sources of great confusion. European Review for Medical and Pharmacological Sciences (2020).
HARRISON I. P. & et al. Skin cleansing without or with compromise: Soaps and syndets. Molecules (2022).
