Diclofenac sodium 3% gel is a prescription topical medication used to treat actinic keratoses, the rough, scaly patches of skin caused by years of sun exposure. These patches are considered precancerous, meaning they can develop into squamous cell skin cancer if left untreated. The gel offers a non-invasive alternative to procedures like freezing or scraping, allowing you to treat the affected skin at home over the course of several weeks.
What Are Actinic Keratoses?
Actinic keratoses (AKs) are small, rough spots that develop on skin that has had significant sun exposure over time. They’re most common on the face, scalp, ears, neck, forearms, and backs of the hands. The patches often feel like sandpaper and may be pink, red, or skin-colored. They’re especially common in fair-skinned adults over 40, though anyone with a history of sun exposure or tanning bed use can develop them.
While most individual AKs won’t become cancerous, there’s no reliable way to predict which ones will progress. Dermatologists generally recommend treating them rather than watching and waiting, particularly when multiple lesions are present in one area. Diclofenac sodium 3% gel is one of several topical options for this purpose.
How the Gel Works
Diclofenac belongs to the NSAID (non-steroidal anti-inflammatory drug) family, the same class as ibuprofen. But its effect on precancerous skin goes beyond simple inflammation control. The gel triggers abnormal cells to self-destruct through a process called apoptosis, while also disrupting how those cells fuel their growth. Research published in Frontiers in Oncology found that diclofenac reduces the ability of precancerous cells to take in glucose and produce energy, essentially starving them.
The gel also appears to boost the skin’s own immune defense. In responding lesions, treatment led to an increase in a type of immune cell (CD8+ T cells) that targets abnormal cells, along with markers of improved immune function. This dual action, cutting off the cells’ energy supply while ramping up the immune response, helps explain why the gel can clear lesions that have been building for years.
How Effective It Is
In the clinical trial that led to FDA approval, 47% of patients using diclofenac sodium 3% gel achieved complete clearance of their lesions at a 30-day follow-up after treatment, compared to 19% of patients using a placebo gel. Lesions on the head and neck responded best, with a 52% complete clearance rate versus 26% for placebo. Lesions on the hands and forearms cleared completely in about 40% of patients.
For patients whose lesions did clear, the average time to full resolution was roughly 74 days. Even when complete clearance didn’t occur, many patients saw a significant reduction in the number and size of their lesions. These numbers make diclofenac 3% gel a moderate-strength option. It tends to be better tolerated than some alternatives like fluorouracil cream, though those stronger treatments often have higher clearance rates.
How to Apply It
The standard regimen is applying the gel to affected skin areas twice daily. Treatment typically continues for 60 to 90 days, and sticking with the full course matters even if you don’t see visible changes early on. The gel works gradually, and stopping early reduces your chances of clearing the lesions.
After applying the gel, let the area dry completely before putting on clothing, sunscreen, or any other topical product. Avoid showering or bathing for at least one hour after application. The gel should not be applied to open wounds, infected skin, or areas with peeling dermatitis. It is also not approved for use in children.
Common Side Effects
Most side effects are localized to the skin where you apply the gel. Redness, dryness, scaling, and mild itching or irritation at the application site are the most frequently reported reactions. Some people notice a rash or mild dermatitis in the treated area. These effects are generally manageable and tend to resolve after treatment ends.
Because the gel is applied to the skin rather than taken by mouth, very little of the drug reaches your bloodstream. Studies show that only about 10% of the applied dose is absorbed systemically, even on compromised skin. That’s substantially less than what you’d absorb from an oral NSAID pill, which makes serious systemic side effects uncommon. Still, the medication carries the same class-wide NSAID warnings.
Who Should Avoid This Gel
You should not use diclofenac sodium 3% gel if you have a known allergy to diclofenac or any of the gel’s inactive ingredients. People who have had allergic reactions to other NSAIDs (such as aspirin or ibuprofen) should also avoid it.
The gel carries specific cautions for people with cardiovascular concerns. It should not be used shortly after coronary artery bypass surgery, and people with a recent heart attack or severe heart failure should use it only when the benefit clearly justifies the risk. Those with active stomach or intestinal ulcers, serious kidney problems, or significant liver disease should use the gel with caution.
Pregnant women should avoid it from about 20 weeks of gestation onward. Later in pregnancy (around 30 weeks and beyond), NSAIDs including this gel can cause premature closure of a critical blood vessel in the fetus and may impair fetal kidney function.
How It Compares to Other AK Treatments
Diclofenac 3% gel is one of several topical treatments for actinic keratoses. Its main advantage is tolerability. The skin irritation it causes is typically milder than what patients experience with stronger topical options, which can produce intense redness, crusting, and discomfort for weeks. The tradeoff is a longer treatment period (two to three months versus a few weeks for some alternatives) and somewhat lower clearance rates.
For people with scattered individual lesions, spot treatments like cryotherapy (freezing) remain common. Topical options like diclofenac gel are particularly useful for “field treatment,” where an entire area of sun-damaged skin contains multiple lesions or early changes that aren’t yet visible. By treating the whole field, you address both the spots you can see and the underlying damage you can’t.