Which relaxer is considered stronger and more caustic, typically used to straighten tight curl patterns?

• A. Sodium Hydroxide
• B. Guanidine hydroxide relaxer
• C. Ammonium thioglycolate
• D. Potassium hydroxide

Answer: (A)

The strongest relaxers are the most alkaline, meaning they have the highest pH and act more aggressively to break and realign the hair’s disulfide bonds. This level of strength is what allows them to straighten very tight curls, but it also comes with greater risk of scalp irritation and damage if not applied and neutralized properly.

Sodium hydroxide fits this description best. It’s a lye relaxer with an extremely high pH, giving it the strongest chemical action among common relaxers, which is why it’s typically used for very resistant curl patterns. Because of its potency, it requires careful handling and precise timing.

Other options are milder or use different chemistry. Potassium hydroxide is another strong option but is generally considered less harsh than sodium hydroxide in practice. Guanidine hydroxide and ammonium thioglycolate are no-lye/thioglycolate systems, which are milder and often chosen for less resistant textures or when gentler processing is preferred.