Formulation and Evaluation of Pot Marigold (Calendula officinalis) Herbal Soap for Anti‑Acne Activity

Acne vulgaris is a common inflammatory disorder of the pilosebaceous unit, associated with Cutibacterium acnes proliferation, excess sebum production, and inflammation. This study aims to formulate and evaluate a Pot marigold (Calendula officinalis) herbal soap as a safer, plant-based alternative to conventional anti-acne products. Petals rich in flavonoids, carotenoids, and triterpenoids were used as infused oil or hydroalcoholic extract and incorporated into a soap base of olive oil, coconut oil, and palm oil or shea butter using cold-process saponification. The formulated soap was evaluated for physicochemical properties such as appearance, color, pH, hardness, lather quality, and stability during curing. Antimicrobial activity was tested against C. acnes, Staphylococcus aureus, and Staphylococcus epidermidis using agar well diffusion and minimum inhibitory concentration methods. Antioxidant activity (DPPH assay) and anti-inflammatory screening were also performed to support the mechanism of action.1 A preliminary skin tolerability study was conducted on acne-prone volunteers using the soap twice daily for 2–4 weeks, with lesion count and irritation recorded. Results showed that the calendula-based soap exhibited significant antimicrobial activity against acne-related bacteria, along with moderate antioxidant and anti-inflammatory effects. It also demonstrated good acceptability with minimal irritation. These findings suggest that Pot marigold herbal soap has promising potential as a mild and effective topical anti-acne cleansing agent.