Skincare ingredients, explained.

How to use these explainers

The Learn library covers the six actives that do most of the heavy lifting in modern skincare: retinol, niacinamide, hyaluronic acid, vitamin C, salicylic acid and peptides. Each explainer follows the same shape. A plain-English answer to what the ingredient is, a method section on how to actually use it, the products we reach for, and the questions readers ask us most.

The product picks inside each explainer carry the same Glow scores and Australian prices as our main rankings, so the education and the shopping never disagree. The retinol explainer, for example, recommends Alpha-H's Vitamin A Serum at 9.1 and $79, The Ordinary's Retinol 1% in Squalane at 8.5 and $12, and The INKEY List's Retinol Serum at 8.4 and $18, the same products and scores you will find in our retinol ranking. Recommendations follow the rubric published on our how-we-review page, and no brand pays for a place in an explainer.

• Read the explainer before the ranking. Knowing what an active does stops you buying the right product for the wrong problem.
• Introduce one new active at a time, so you can tell what is working and what is irritating.
• The method sections cover the details that cause most failures: concentration, timing, and what not to layer together.
• Check the common questions at the end of each guide first. Most routine-order dilemmas are already answered there.

Begin with what is retinol, or with what is niacinamide for the gentlest of the proven actives.