The disadvantages of commercial soaps

The disadvantages of commercial soaps

Most commercial soaps have had their glycerine removed for use in other industries, which deprives the skin of the natural, moisturizing glycerine and generally leaves the skin feeling dry.

Some antibacterial soaps have antiseptic chemicals that can kill "healthy" bacteria that live symbiotically on the skin's surface and contribute to skin health. There is a theoretical risk of antibacterial additives, such as Triclosan, in soaps contributing to antibiotic resistant bacteria, however, controlled studies have not borne out that conclusion. [2] When Triclosan is discharged into the environment and exposed to sunlight, it breaks down to yield dioxins. [3]

Soap-based products often contain the additive detergent sodium laureth sulfate, which research has found to be harsh on skin. This product is also present in many non-soap cleaners for personal hygiene (shampoos, bathfoams, toothpaste, etc.).

Soap can have a mild base reaction with fabrics, resulting in damage over the long term. This could be due to excess sodium hydroxide ( NaOH, an alkali/ base) left from manufacture. This, however, is highly unlikely since most soap manufacturers don't formulate their soaps to have excess lye but rather excess oil or fat. It could also be caused by the very slight presence of NaOH from the equilibrium reaction:
R-COO-Na + H2O ↔ R-COO- + Na+ + H2O ↔ R-COOH + NaOH
However, this equilibrium strongly favors the left-hand side so the fraction of NaOH formed is minuscule. It could simply be that soap itself is more alkaline in general and that this, in and of itself, is the cause for the damage.

Soap reacts with lime to form an insoluble deposit (soap scum) in " hard water":
2Na+(R-COO)- (aq) + Ca2+(HCO3-)2(aq) 2Na+(HCO3)-(aq) + Ca(R-COO)2(s) - where R stands for an alkyl group ( ppt)

Poorly finished soaps may contain excess alkali ( NaOH) and react mildly basically with skin and fabric; Most handmade and commercial products are finished to neutrality or to a weak acid content to prevent this and be more compatible with the skin's slightly acidic pH.

Commercial products use chelating molecules ( sequestrants), often EDTA derivatives to bind with any free Ca or Mg ions and prevent soap scum. These also help reduce fragrance loss, discoloration and rancidity.

Castile soap has a very high alkalinity level, measured at about 9. pH of skin and hair has a slightly acidic pH level known to be about 5 to 6. Due to the high pH level, soapmakers who market liquid castile soap do not usually recommend it for washing hair, because it may cause hair to become dry. Those that do often recommend an acidic final rinse, such as with diluted vinegar, to restore the pH and remove any soap scum resulting from rinsing with hard water.