Sources that compare tretinoin strengths report efficacy and irritation side by side. In one double-blind trial in photoaged patients, 0.1% and 0.025% tretinoin creams showed no clinically or statistically significant differences in efficacy, and irritant side effects (erythema and scaling) were statistically significantly greater with 0.1%. These are group findings. They do not say which strength is better for any one person, and a licensed provider decides that.
Photoaged patients: 0.1% versus 0.025% over 48 weeks
The 1995 Archives of Dermatology report describes 99 photoaged patients who completed a 48-week study using 0.1% tretinoin cream (n = 32), 0.025% tretinoin (n = 35), or vehicle (n = 32) once daily, in a double-blind manner.
On efficacy, both strengths produced statistically significant overall improvement in photoaging of the face compared with vehicle. The abstract reports no clinically or statistically significant differences in efficacy between 0.1% and 0.025%. On irritation, erythema and scaling were statistically significantly greater with 0.1% than with 0.025% by various analyses. The authors concluded that the two strengths produce similar clinical and histologic changes, despite a significantly greater incidence of irritation with the higher concentration.
Healthy volunteers: irritation only
A 1998 report in the British Journal of Dermatology enrolled 55 healthy human subjects, not acne or photoaging patients, in two controlled, randomized, observer blinded, intraindividual comparison studies of irritation. In study B, the abstract lists three groups in descending order of irritancy: tretinoin 0.1% cream; then tretinoin 0.05% cream, tretinoin 0.025% cream and tretinoin 0.1% gel microsphere; then adapalene 0.1% gel and petrolatum (control).
The 0.05% and 0.025% creams sit in the same group, so that abstract does not separate them. Because the subjects were healthy and the studies measured irritation, this report does not show whether any strength improved acne or photoaging.
Other studies that name a strength
Each row reports only what the linked abstract states.
| Question | What the source says |
|---|---|
| Photodamage: 0.05%, 0.01% and 0.001% emollient cream? | A 24-week, double-blind, randomized, multicenter study of 296 subjects with photodamaged facial skin compared the three concentrations with vehicle. Tretinoin emollient cream 0.05% gave a significantly better global response than vehicle, with 68% of subjects improved at the end of therapy compared with 43% in the vehicle group. This guide uses only the 0.05% result. |
| Photodamage: what did a Cochrane review report? | In a Cochrane review (literature searched to June 2002), eight trials showed tretinoin cream in concentrations of 0.02% or higher was superior to placebo for mild to severe photodamage on the face and forearms, although losses to follow-up were relatively high in most studies. The effect was not seen for 0.001% (one study) or 0.01% (three studies). A dose-response relationship was evident for both effectiveness and skin irritation. |
| Acne: two 0.025% creams? | A 12-week, double-blind study in patients with mild to moderate acne enrolled 271 patients. The two 0.025% creams (strength from the paper's title) showed comparable efficacy that was statistically significantly greater than vehicle. |
| Acne: Tretin-X versus Retin-A at 0.1% and 0.025%? | In a study of 1642 adolescents and adults, 12-40 years of age, with mild-to-severe acne, people were randomly assigned to Tretin-X, Retin-A, or placebo as 0.1% cream (study 1) or 0.025% cream (study 2), among other products. In each trial the two products were clinically equivalent at Weeks 2, 4, 8, and 12. The comparison in each trial is between products, not between strengths. |
| Acne: adverse events in a systematic review? | A systematic review of topical retinoids reports that tretinoin 0.05% resulted in 62% of patients experiencing adverse events compared with adapalene 0.1% (19%) and adapalene 0.3% (40%). This compares tretinoin with a different drug, not one tretinoin strength with another. |
What the labels say about strengths
The Retin-A label states that Retin-A cream contains tretinoin in one of three strengths, 0.1%, 0.05%, or 0.025% by weight, in a hydrophilic cream vehicle.
The Renova (tretinoin cream) 0.02% label states that no studies have been conducted comparing the facial irritation or efficacy of Renova 0.02% to Renova 0.05% (older marketed formulation).
What this does not tell you
None of these sources says which strength is better for a given person. A licensed provider decides that. The photoaging trial compared 0.1% with 0.025% and did not include 0.05%. The healthy-volunteer report measured irritation only. A result at one strength should not be applied to another. This guide reports only the comparisons found in the sources linked here.
The labels and trials describe specific products and creams that were studied. The FDA states that compounded drugs are not FDA-approved, meaning FDA does not verify the safety, effectiveness or quality of compounded drugs before they are marketed. A finding for an approved or manufactured product should not be read as a finding for a compounded cream.