How does tretinoin work for acne?

What does tretinoin do inside the skin?

Acne starts when hair follicles become blocked with excess oil and dead skin cells. Bacteria can grow inside those blocked follicles, causing inflammation and pus. Tretinoin is a retinoid, a medicine related to vitamin A. It encourages new skin growth and the shedding of old cells, helping open blocked pores.34

Retinoids work inside skin cells by binding to receptors that control gene activity. These signals change how keratinocytes, the cells that make up the outer skin layer, function. Tretinoin is therefore more than a surface exfoliant: its action begins at the cellular level.5

Which types of acne can it treat?

Topical retinoids are a standard initial treatment for blackheads, whiteheads and inflamed acne. They suit mild to moderately severe acne, but tretinoin alone is not recommended for severe acne with deep nodules or cysts. A dermatologist can combine treatments to address blocked pores, bacteria, inflammation and excess oil. Retinoids can also help lighten dark marks left after acne and serve as maintenance treatment once breakouts are controlled.256

How long does tretinoin take to work?

Acne can look worse during the first 7 to 10 days. Some spots improve after 2 to 3 weeks, but allow at least 6 to 8 weeks to assess fewer breakouts. Topical retinoids can take 12 weeks or longer to show improvement. Early worsening and the later treatment response are different stages, not conflicting deadlines. Improvement can gradually disappear if you stop tretinoin.125

How should you apply tretinoin?

A gentle cleanser belongs in an acne routine, even if its packaging has no dramatic transformation to announce. Remove makeup before bed and avoid harsh products or excessive exfoliation.34

1. 1Wash your hands and affected skin with a mild cleanser, then let the skin dry as directed.
2. 2Use clean fingertips to spread a thin layer over the affected area. Avoid eyes, lips, nose corners, sunburned skin and eczema.
3. 3Apply at bedtime, usually daily, following your prescription. Do not use extra or apply more often than directed.
4. 4If irritation develops, ask your dermatologist about a smaller amount, less frequent use or moisturizer before tretinoin. Make these changes with their help.

What should you use alongside tretinoin?

Choose moisturizer, sunscreen and makeup labelled noncomedogenic, meaning formulated not to clog pores, which is a useful job description rather than a personality. For daytime protection, use sunscreen with broad spectrum protection, SPF 30 or higher and water resistance, alongside shade and protective clothing. Retinoids can cause sun sensitivity, and moisturizer helps manage dryness.256

Do not add benzoyl peroxide, salicylic acid or other topical medicines without checking with your prescriber. Combination treatment can be useful, but the medicines and directions need to fit your treatment plan.12

When should you contact a doctor?

Dryness, redness and peeling are common retinoid effects; irritation does not automatically mean an allergy. Report severe or persistent irritation. Call your doctor immediately for rash, hives or pain at the treated area rather than treating these as ordinary early worsening.125

Tell your prescriber before starting if you are pregnant, planning pregnancy, breastfeeding or have eczema. Call your doctor if you become pregnant during treatment.1

Seek a treatment review if acne is not improving, is deep or painful, causes scars or affects your mental health. Widespread or severe acne can need treatment beyond a topical retinoid.34