Duac Once Daily Gel is a prescription-only combination treatment for acne containing two active ingredients: clindamycin 1% (a topical antibiotic) and benzoyl peroxide 5%. It is one of the most commonly prescribed topical acne treatments in the UK.
How Does Duac Work?
The two ingredients work together through complementary mechanisms:
- Clindamycin kills C. acnes bacteria and reduces inflammation within the pore.
- Benzoyl peroxide provides additional antibacterial action and — crucially — prevents the bacteria from developing resistance to clindamycin.
This combination is more effective than either ingredient used alone and addresses the NICE guideline requirement that topical antibiotics should never be used as monotherapy.
How to Use Duac Gel
- Apply a thin layer once daily in the evening to clean, dry skin.
- Cover the entire acne-affected area, not just individual spots.
- Wash your hands thoroughly after application.
- Allow the gel to dry before applying moisturiser or going to bed.
- Store Duac in the fridge — it must be kept between 2°C and 8°C and used within two months of opening.
Important Precautions
- Duac contains benzoyl peroxide, which bleaches fabrics. Use white bedding and towels.
- Avoid excessive sun exposure and use SPF 30+ during the day.
- Do not combine with other topical antibiotics (e.g., topical erythromycin).
How Long Does Treatment Last?
A typical course of Duac is 12 weeks. Improvement is usually noticeable after 4–6 weeks. After the course ends, your prescriber may switch you to a maintenance treatment such as adapalene or benzoyl peroxide alone to keep acne at bay.
Side Effects
The most common side effects are dryness, peeling, and mild stinging at the application site. These typically ease after the first two weeks. If irritation is severe, try applying every other night initially, or use a gentle moisturiser before application to buffer the effect.
Duac is an effective, well-established treatment. If your GP or pharmacist prescribes it, follow the instructions carefully and give it the full 12 weeks to work.