Accutane’s active ingredient is isotretinoin, a synthetic compound derived from vitamin A with the molecular formula C₂₀H₂₈O₂. Originally approved by the FDA on May 7, 1982 and manufactured by Hoffmann-La Roche, the brand name Accutane is no longer sold, but several generic versions of isotretinoin remain widely prescribed for severe acne.
The Active Ingredient: Isotretinoin
Isotretinoin is a lab-made form of retinoic acid, which is a compound your body naturally produces from vitamin A. Specifically, it’s the 13-cis isomer of retinoic acid, meaning its atoms are arranged in a slightly different geometric shape than the form your body typically uses. That small structural difference turns out to matter enormously for how it affects oil glands in the skin. With a molecular weight of 300.44, it’s a relatively small molecule, and it’s highly fat-soluble, which is why it’s dissolved in oil inside a soft gel capsule.
What’s Inside the Capsule
The isotretinoin itself only accounts for 10 to 40 milligrams of each capsule, depending on the prescribed strength (capsules come in 10 mg, 20 mg, 25 mg, 30 mg, 35 mg, and 40 mg). The rest of the capsule is made up of inactive ingredients that help the drug dissolve, stay stable, and get absorbed properly.
One key inactive ingredient is hydrogenated soybean oil, which serves as the lipid base that keeps isotretinoin dissolved. This is important for anyone with a soy allergy: isotretinoin is considered contraindicated for people allergic to soy because of this ingredient. The outer shell is a soft gelatin capsule, and various formulations include additional ingredients like beeswax, coloring agents, and other oils to maintain consistency and shelf life.
Why It Needs to Be Taken With Fat
Because isotretinoin is so fat-soluble, what you eat alongside it dramatically changes how much your body actually absorbs. Taking traditional isotretinoin on an empty stomach can reduce the amount that reaches your bloodstream by about 60 percent compared to taking it with a high-fat meal. That’s not a minor difference. Skipping the fat means you’re effectively getting a fraction of your prescribed dose, which can lead to inconsistent drug levels and a less effective treatment course.
Newer formulations like Absorica were designed to reduce this problem. Absorica’s bioavailability drops by only about 33 percent on an empty stomach, making it somewhat less dependent on meal timing. But for standard isotretinoin capsules, eating something with a meaningful amount of fat (think peanut butter, avocado, or a meal cooked with oil) alongside each dose is essential.
How Isotretinoin Works in the Body
The reason isotretinoin is so effective against severe acne comes down to what it does to the oil-producing glands in your skin, called sebaceous glands. It’s the only retinoid that dramatically reduces both the size and the output of these glands. It does this through two mechanisms: it slows down the rate at which oil gland cells multiply, and it triggers those cells to self-destruct through a process called apoptosis.
Research published in the Journal of Clinical Investigation showed that within just one week of treatment, the percentage of dying cells inside sebaceous glands roughly tripled compared to baseline. The drug accomplishes this by ramping up production of a protein called NGAL, which is part of the body’s innate immune system and has the ability to trigger cell death. When researchers blocked the gene responsible for producing NGAL, the cell-death signal dropped by about 80 percent, confirming that this protein is the primary driver of how isotretinoin shrinks oil glands.
The drug also activates other genes involved in regulating cell growth and death, which likely contributes to its broad effectiveness. By simultaneously cutting oil production, killing overactive gland cells, and slowing the creation of new ones, isotretinoin addresses the root cause of severe acne rather than just managing symptoms on the surface.
Its Relationship to Vitamin A
Isotretinoin is classified as a retinoid, meaning it belongs to the family of compounds related to vitamin A. Your body naturally converts dietary vitamin A into various active forms, including small amounts of retinoic acid. Isotretinoin is essentially a concentrated, targeted version of one of those natural metabolites.
This relationship is why taking vitamin A supplements while on isotretinoin is a concern. Stacking the drug with additional vitamin A can amplify side effects like dry skin, headaches, and in extreme cases, a dangerous buildup called hypervitaminosis A. The drug is already pushing your body’s retinoid pathways hard, so adding more through supplements creates an excess your liver has to deal with.