Glycerin

Glycerin is 甘油 (gān yóu) in Chinese — the same characters in Simplified and Traditional (Taiwan) — and is also known chemically as 丙三醇. It's the classic humectant that draws moisture into the skin's outer layer to keep it hydrated.

No — with one caveat. The claim that glycerin "pulls water out of skin" only holds in extremely dry air (below ~30% relative humidity). At normal indoor humidity it draws water from the air. Pair it with an oil or cream to seal moisture in — a glycerin lotion beats a plain glycerin solution.

No. 5-10% is the sweet spot — effective hydration without stickiness. Above 15% it gets noticeably tacky, can clog pores, and may trigger breakouts, especially on oily or acne-prone skin. If a product feels too sticky, dilute it with a lighter hydrating lotion.

Yes, at the right concentration. Low levels (5-8%) are completely safe for acne-prone skin and actually support barrier repair. Avoid high concentrations or using it solo; stick to light lotion or gel textures rather than heavy occlusives. Glycerin plus sodium hyaluronate is an ideal lightweight combo.

Yes. Glycerin conflicts with almost nothing and even improves the stability of niacinamide, sodium hyaluronate, and vitamin C. Best pairings: (1) oils like squalane or petrolatum to prevent water loss; (2) ceramides and cholesterol for barrier repair; (3) sodium hyaluronate for extra water-binding. Combinations outperform glycerin alone.

No. Glycerin doesn't suppress your skin's own moisturizing function — long-term use improves hydration and barrier strength. If skin worsens after stopping, that's dry conditions plus missing hydration, not withdrawal: your skin had improved, then rapidly lost water without a humectant.