During a perm, what is the function of the waving lotion?

The waving lotion used during a perm serves the crucial function of breaking down the hair's natural structure. This chemical solution contains active ingredients, often thioglycolic acid or its derivatives, that penetrate the hair shaft and alter the disulfide bonds within the hair's keratin. By breaking these bonds, the hair becomes more pliable and can be reshaped into new forms, such as curls or waves, when wrapped around perm rods.

This process is vital for achieving long-lasting waves or curls, as it allows the hair to retain its new shape once the waving lotion is neutralized with a fixing solution. Without this breakdown of the natural structure, the hair would not be able to transition from straight to curled efficiently.

The other options focus on aspects not directly related to the primary function of waving lotion. While moisturizing and adding shine may be beneficial qualities in hair care products, they are not the main purpose of waving lotion. Similarly, while providing hold for curls is a desirable outcome of the perming process, it is the alteration of the hair structure that enables that outcome to occur.