RetinoidsRetinoidA class of vitamin-A-derived compounds that regulate cell differentiation and skin renewal via the retinoid receptors (RAR/RXR).
Isotretinoin vs Tretinoin
The table compares the compounds’ key data from their entry pages. Open each compound’s full entry for details. Educational content, not medical advice.
 Isotretinoin |  Tretinoin | |
|---|---|---|
| What it is | 13-cis-retinoic acid (Roche Roaccutane). Gold standard for severe nodulocystic acne. FDA category X due to severe teratogenicity – iPLEDGE program mandatory. | Topical retinoid all-trans-retinoic acid. Acne, photoaging, hyperpigmentation treatment. Dermatological gold standard. |
| ATC codeATC codeThe WHO Anatomical Therapeutic Chemical code that classifies drugs by organ system and mechanism. | D10BA01 | D10AD01 |
| Prescription | Prescription only (Rx), iPLEDGE/pregnancy prevention | Prescription only (Rx), dermatologist-supervised |
| MechanismMechanism of actionThe molecular pathway by which a compound acts in the body (e.g. which receptor or enzyme it binds). | Retinoid (RAR agonist), sebaceous gland suppression | RAR-α/β/γ retinoid receptor agonist (all-trans-retinoic acid) |
| Half-lifeHalf-lifeThe time for the compound’s plasma concentration to fall by half; indicates how fast it clears and how often it is dosed. | ~21 h (active 4-oxo metabolite ~24 h) | Topical, minimal systemic absorption |
| OnsetOnsetThe time from dosing until a measurable effect appears. | 4-8 weeks (initial), 15-20 weeks full course | 8-12 weeks (acne), 4-6 months (anti-aging) |
| Full entry | Open → | Open → |
What it is
Isotretinoin13-cis-retinoic acid (Roche Roaccutane). Gold standard for severe nodulocystic acne. FDA category X due to severe teratogenicity – iPLEDGE program mandatory.
TretinoinTopical retinoid all-trans-retinoic acid. Acne, photoaging, hyperpigmentation treatment. Dermatological gold standard.
ATC codeATC codeThe WHO Anatomical Therapeutic Chemical code that classifies drugs by organ system and mechanism.
IsotretinoinD10BA01
TretinoinD10AD01
Prescription
IsotretinoinPrescription only (Rx), iPLEDGE/pregnancy prevention
TretinoinPrescription only (Rx), dermatologist-supervised
MechanismMechanism of actionThe molecular pathway by which a compound acts in the body (e.g. which receptor or enzyme it binds).
IsotretinoinRetinoid (RAR agonist), sebaceous gland suppression
TretinoinRAR-α/β/γ retinoid receptor agonist (all-trans-retinoic acid)
Half-lifeHalf-lifeThe time for the compound’s plasma concentration to fall by half; indicates how fast it clears and how often it is dosed.
Isotretinoin~21 h (active 4-oxo metabolite ~24 h)
TretinoinTopical, minimal systemic absorption
OnsetOnsetThe time from dosing until a measurable effect appears.
Isotretinoin4-8 weeks (initial), 15-20 weeks full course
Tretinoin8-12 weeks (acne), 4-6 months (anti-aging)
Full entry