The key difference between sodium lauryl sulfate and sodium lauroyl sarcosinate is that sodium lauryl sulfate is comparatively less gentle on hair and scalp, whereas sodium lauroyl sarcosinate is more gentle on the hair and scalp.
Both sodium lauryl sulfate and sodium lauroyl sarcosinate are surfactants. They even have the same denotation, SLS, but they are very different from each other.
CONTENTS
1. Overview and Key Difference
2. What is Sodium Lauryl Sulfate
3. What is Sodium Lauroyl Sarcosinate
4. Sodium Lauryl Sulfate vs Sodium Lauroyl Sarcosinate in Tabular Form
5. Summary – Sodium Lauryl Sulfate vs Sodium Lauroyl Sarcosinate
What is Sodium Lauryl Sulfate?
Sodium lauryl sulfate, or SLS, has many synonyms, such as sodium dodecyl sulfate (SDS), lauryl sodium sulfate, lauryl sulfate sodium salt, sodium N- dodecyl sulfate, etc. The structural formula of this compound is CH3-(CH2)11-O-SO3-Na+. It is popular as a good cleaning agent and is included in various cleaning products and toiletries. However, laboratory experiments have proven that SLS is a skin irritant. It causes severe damage to normal skin by disturbing its natural balance. Therefore, skin becomes permeable to other chemical substances. Sensitive skins are most easily damaged by SLS, and longer-term usage can cause itchy, cracked dry skin. Further, it becomes toxic if it enters in oral route.
Sodium lauryl sulfate causes eye irritations too. Since it causes skin irritations, people avoid using products with sodium lauryl sulfate. Hence, sodium laureth sulfate has replaced this compound. Shampoos with SLS may increase hair falling and hair thinning. Using toothpaste with SLS can cause mouth ulcers. However, SLS is not carcinogenic, but it can react with other chemicals in cosmetic products to produce nitrosamines which are carcinogenic.
Figure 01: The Chemical Structure of Sodium Lauryl Sulfate
Sodium lauryl sulfate is also an emulsifying and dispersing agent. Because of its emulsifying and thickening ability, we can use it as a food additive. It is also useful in laboratories for nanoparticle preparation and protein separation by electrophoresis (SDS—PAGE technique).
What is Sodium Lauroyl Sarcosinate?
Sodium lauroyl sarcosinate is an anionic surfactant that is derived from sarcosine, and it is useful as a foaming and cleansing agent for shampoo, shaving foam, toothpaste, and foam wash products. It is an amphiphilic compound because of its hydrophobic 12-carbon chain and hydrophilic carboxylate. The nitrogen atom is an amide linkage. Therefore, the nitrogen is not pH active. Then it stays neutral charged in all the aqueous solutions without concern for pH value.
Figure 02: The Chemical Structure of Sodium Lauroyl Sarcosinate
There are pH-sensitive vesicles that are prepared from this surfactant in the presence of other cationic or water-insoluble amphiphiles, including 1-decanol. If we add a mixture consisting of two equal parts of sodium lauroyl sarcosinate and nonionic surfactant sorbital monolaurate to water, it will give the formation of micelle-like aggregates. These aggregates can help in carrying other small molecules, including drugs, through the skin.
What is the Difference Between Sodium Lauryl Sulfate and Sodium Lauroyl Sarcosinate?
Sodium lauryl sulfate and sodium lauroyl sarcosinate are important industrial organic chemicals. The key difference between sodium lauryl sulfate and sodium lauroyl sarcosinate is that sodium lauryl sulfate is comparatively less gentle on hair and scalp, whereas sodium lauroyl sarcosinate is more gentle on the hair and scalp. Therefore, sodium lauroyl sarcosinate is used for baby products while sodium lauryl sulfate is not.
Below is a summary of the difference between sodium lauryl sulfate and sodium lauroyl sarcosinate in tabular form for side-by-side comparison.
Summary – Sodium Lauryl Sulfate vs Sodium Lauroyl Sarcosinate
The key difference between sodium lauryl sulfate and sodium lauroyl sarcosinate is that sodium lauryl sulfate is comparatively less gentle on hair and scalp whereas sodium lauroyl sarcosinate is more gentle on the hair and scalp.
Reference:
1. “Sodium laureth sulfate.” Wikipedia. Wikipedia Foundation.
Image Courtesy:
1. “Sodium laureth sulfate structure” By Edgar181 – Own work (Public Domain) via Commons Wikimedia
2. “Sodium lauroyl sarcosinate” By Fvasconcellos 00:03, 23 December 2007 (UTC) – Own work (Public Domain) via Commons Wikimedia