Ingredient notes for breakout-prone skin
Salicylic acid, niacinamide, centella, panthenol and more, one per article: how often to start, when to stop, and what studies have found, with sources.
13 articlesLast reviewed Oct 1, 2026
- Aloe Vera Gel First Use: A 3-Step Patch Test and Summer StorageStarting a new aloe vera gel: a 3-step test from inner arm to jawline to full face, how to scoop and store it, and how to use it after a lot of sun, with a log.
- Azelaic Acid, the First 4 Weeks: A Sting Log and Split ScheduleAzelaic acid is banned from cosmetics in Korea. Here is a log of time, amount and sting for your first 4 prescribed weeks, and what to ask about splitting days.
- Ceramide Cream Too Heavy? Try Lotion, Toner or Ampoule TexturesWhen ceramide cream feels heavy or you worry about tiny bumps, how to pick a lotion, toner, ampoule or spray, plus a 2-week chart for bumps and tightness.
- Cica Cream: Reading the Centella Label and When to Start or StopHow to find and read Centella Asiatica Extract, Leaf Water and Madecassoside on a cica cream label, and when to add or drop it for seasonal or mask breakouts.
- How to Layer Hyaluronic Acid: How Many Coats for a Dry RoomHow many coats of a hyaluronic acid ampoule to apply, what to change on days the heater or AC dries the room, and a weekly plan for vitamin C and retinol days.
- How to Test New Skincare Products for Clogged Pores Over 4 WeeksEven with a non-comedogenic label, try each new cream, sunscreen, or cushion alone and count bumps on one jaw side for 4 weeks. Plus reading oils and esters.
- Niacinamide Morning or Night: Weekly Vitamin C and Retinol PlanMorning or night for niacinamide, how to split it by weekday from vitamin C, retinol, and acids, and when to take a break, all in one weekly calendar.
- How to Use Panthenol Cream the Day After Exfoliating or ShavingWhen to use panthenol cream after exfoliating or retinol, after shaving, on mask marks, and on windy days: how much, how often to reapply, and when to stop.
- PDRN Serum Before and After: A 4-Week Photo and Reaction LogWhat to expect, and not expect, from 4 weeks of a PDRN ampoule or cream, how to take same-condition photos, why not to swap products, and cautions for teens.
- Retinol Schedule for Beginners: 8 Weeks From Twice a Week to DailyA first 8 weeks of retinol, going from twice a week to every other day to nightly, what to do on rest nights, and when to think about moving on to retinal.
- Salicylic Acid for Beginners: Your First 2 Weeks, Day by DayThe first 2 weeks with a salicylic acid cleanser, BHA toner, pad, or serum: pick one format, set days per week, then log tightness, stinging, and flaking.
- Does Tea Tree Oil Go Bad? Storage, Oxidation, and an Arm Test LogHow to store tea tree oil away from light and air once opened, how to spot oil that has oxidized with age, and how to log a few days of inner-arm testing.
- How to Store Vitamin C Serum, Read Its Label, and Spot OxidationTelling pure vitamin C from derivatives on an ampoule label, when a color change after opening means replace it, storage, and layering it with cica cream.
