TLDR Hair can be straightened using different chemicals, not just strong alkali.
The document discussed the practice and theory of permanent hair straightening, noting that while it was commonly believed to require high pH with strong alkali, it could also be achieved at neutral pH with lithium salt or at acidic pH with resorcinol. The treatments varied in their effects on cystine, with some causing significant loss and others leaving it intact. Lanthionine production was also variable. The key requirement for effective hair straightening was the ability to induce supercontraction of the hair fiber.
January 2010 in “SÖFW-Journal” The document discussed the importance of hair in human image and the role of cosmetic formulations in altering hair's physical properties. It highlighted that hair is primarily composed of keratin, which is crucial for its tensile strength. The study noted that a single healthy hair requires 50-100 grams of force to rupture, and with an average of 120,000 hairs on a human head, the combined strength could support six to twelve tons. The research focused on improving these tensile properties using a natural moisturizer.
47 citations
,
November 2007 in “The journal of investigative dermatology. Symposium proceedings/The Journal of investigative dermatology symposium proceedings” Healthy hair is shiny, smooth, and has clean ends.
3 citations
,
January 2002 in “Springer eBooks” Alkaline hair relaxers damage hair, but cationic and non-ionic polymers can help reduce this damage.