L-ascorbic acid is the most clinically studied form and delivers the strongest brightening efficacy at 10–20%, but it requires a pH of 2.5–3.5 and is highly unstable in water. Sodium ascorbyl phosphate and ascorbyl glucoside are more stable alternatives suited to higher-pH formulas and sensitive-skin positioning. A cosmetic chemist you connect with through AJ Cosmo Labs can recommend the right derivative based on your target claims, packaging type, and desired shelf life.
Read the full guide on private label vitamin c brightening serum low moq →