But if there’s one debate dermatologists and facialists are asked time and time again, it’s which ingredient is better: glycolic acid versus salicylic acid. Salicylic acid has long been the go-to for tackling breakouts and congested pores, while glycolic acid is celebrated for its ability to brighten dull skin, smooth texture, and soften the appearance of fine lines over time. Ahead, experts explain the difference between glycolic acid and salicylic acid, which ingredient is best for different skin types and the formulas worth investing in. What’s the difference between glycolic acid and salicylic acid? If skincare ingredients had personalities, glycolic acid would be the overachieving perfectionist, while salicylic acid would be the cool-headed problem solver.