Bond builders

Bleach and chemical services break disulfide bonds in hair keratin. Olaplex's patented approach uses bis-aminopropyl diglycol dimaleate, a maleate compound described in its patent as reacting with free thiol groups to link broken sulfur bonds. K18 uses a proprietary peptide the company says enters the hair and reconnects broken keratin chains. Other 'bond' products rely on maleic acid, amino acids or conditioning polymers. All aim to reduce breakage and restore strength and softness rather than change how hair grows.

In our directory: It’s a key ingredient in 2 products we review, most often wash day and treatments. Those products are mostly built for damage repair, split ends and frizz control. In formulas, it most often shares the label with biotin, panthenol and argan oil.

Follow the specific system: pre-shampoo treatments are left on 10 minutes or more and rinsed; leave-in masks are applied to towel-dried hair and not rinsed. Use weekly or as directed, more often for very damaged hair.

References

1. 1US9095518B2 - Methods for fixing hair and skin — Google Patents (assignee Liqwd Inc., Olaplex)
2. 2Our Science | K18 Hair — K18 Hair
3. 3Hair Cosmetics: An Overview — International Journal of Trichology (2015), via PubMed Central

Educational, not medical advice. Ingredient guides summarise published research and expert guidance; formulas and concentrations differ between products.