Tretinoin vs isotretinoin: which one fits which acne?

Different drugs for different acne

Tretinoin is a topical retinoid, and topical retinoids are recommended as first-line therapy for acne and its sequelae Recommendations review on acne and retinoids. Isotretinoin is an oral retinoid that is typically used for more severe disease. We found no head-to-head trial comparing the two, so the useful question is which one fits your acne.

Tretinoin: modest gains, short trials

Bottom line: topical tretinoin helps mild-to-moderate acne, but the effect is real and not dramatic. A pooled analysis of two phase 3 trials found tretinoin gel 0.05% beat vehicle over 12 weeks in 1,537 people aged 10 and older pooled tretinoin gel analysis.

A phase IV randomized trial with 207 participants found a 0.025% tretinoin nanogel reduced total lesions by 72.9%, compared with 65.0% for conventional gel. Local adverse events were 13.3% versus 24.7%. That trial compared two active treatments rather than using placebo, and we could not confirm its funding source nanogel versus conventional gel trial.

The point to remember is that topical results depend on formulation and patience. Most of the data we reviewed run about 12 weeks, so that is the timeframe to judge against.

Isotretinoin: the dose question is still open

Bottom line: isotretinoin is powerful, but experts still disagree on how much to give and for how long. A 2025 modified-Delphi consensus of 20 dermatology experts preferred conventional dosing of 0.5 to 1 mg/kg/day for conglobate acne and severe nodulocystic acne. It judged low doses acceptable for moderate-to-severe papulopustular acne consensus.

That consensus also reports that a cumulative dose of 220 mg/kg or more reduces relapse without raising adverse-effect rates. The traditional target is 120 to 150 mg/kg. The guidance is expert opinion, not large randomized trials.

Guidelines do not agree. European guidance ranges from 0.3 to 0.5 mg/kg/day and specifies at least six months of treatment, while US guidance goes up to 1 mg/kg/day without a set minimum guideline comparison. A systematic review notes that the 2018 GAIN consensus found no high-quality trial defining a cumulative dose that maintains remission, and it recommends continuing treatment for more than 2 months after clearance hair loss systematic review.

Safety: where the two really differ

Bottom line: topical tretinoin's downside is mostly local irritation. Isotretinoin's side effects are systemic, and teratogenicity is the serious exception. Its other side effects are generally dose-dependent and reversible when treatment stops hair loss systematic review.

• Hair loss was reported in 22 studies of oral isotretinoin, and the review compared frequency at doses below and at or above 0.5 mg/kg/day.
• Hearing impairment, including tinnitus, has been reported with isotretinoin StatPearls.

What to do with this

Bottom line: match the drug to your severity, and let a dermatologist make the call. Most people with mild-to-moderate acne are assessed for topical options first. Isotretinoin decisions depend on severity, pregnancy plans, and monitoring, so they belong with a prescriber who manages the drug.

If you want to learn more about the topical option, see our tretinoin guide.