A permanent wave, or "perm," works by chemically altering the structure of your hair to create a new, lasting curl pattern. This involves breaking and reforming the disulfide bonds within the hair's protein structure.
The Science Behind a Perm
Here's a breakdown of how a perm works on a molecular level:
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Step 1: Hair Preparation and Wrapping: The hair is first washed and then wrapped around perm rods. The size of the rods determines the size and tightness of the resulting curls.
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Step 2: Applying the Perm Solution (Reducing Agent): A chemical solution, typically containing ammonium thioglycolate, is applied. This solution breaks the disulfide bonds in the hair's keratin (protein). Disulfide bonds are responsible for the hair's natural shape and strength. Think of them as bridges holding the protein strands together.
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Step 3: Hair Takes Shape: While the disulfide bonds are broken, the hair can now conform to the shape of the perm rod.
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Step 4: Neutralizing the Hair (Oxidizing Agent): Once the hair has processed sufficiently, the perm solution is rinsed out. A neutralizer, usually hydrogen peroxide, is applied. This step is crucial as it re-forms the disulfide bonds, but now in the curled configuration around the perm rod. This effectively "locks" the hair into its new shape.
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Step 5: Rod Removal and Final Rinse: After the neutralizer has worked, the rods are removed, and the hair is thoroughly rinsed.
Key Considerations
- Not Truly Permanent: While called "permanent," the curled hair only lasts until new hair growth occurs at the roots. The permed portion of the hair remains curled until it is cut off or the chemical bonds are broken through further chemical treatments or excessive heat styling.
- Hair Damage: The chemical process involved in perming can weaken and dry out the hair, leading to potential damage. Proper aftercare, including moisturizing treatments, is essential.
- Hair Type: The effectiveness and longevity of a perm can vary depending on hair type. Coarse or resistant hair may require a stronger perm solution or longer processing time.
In summary, a perm uses chemicals to break and reform the bonds that give hair its shape, allowing it to be molded into curls. While the term suggests forever, the effect is temporary, lasting until new hair grows in or the treated hair is cut off.
