How can one product work both as a skin moisturizer and a soap?

Question

The pharmacist gave me this cream for treating dry/dead skin on fingertips, and she also added that I can use it as a soap as well! The manufacturer also confirms this.

Normally, you don’t apply soap on hands and leave it on to moisturize your hands, and similarly you don’t wash your hands with a hand cream to clean them.

I’d like to understand how one substance can function both as a leave-on moisturizer and a rinse-off cleanser. I see it has alcohol but given it’s a moisturizer, the alcohol percentage is probably low. I couldn’t find any further information on this online. Any idea?

Answer 1

Ingredients listed on the product from the photo:

White soft paraffin (known as petroleum jelly) and cetostearyl alcohol are occlusive agents that decrease water loss through the skin, so they act as moisturizers (Table 4, PubMed).

Sodium lauryl sulfate is a detergent (a surfactant), so it acts as a soap.

Water and soap do not remove paraffin, so the product can work as a moisturizer and soap at the same time.

A very detailed, easy to read article: Moisturizers: A Slippery Road (PubMed, 2016)