TEMPO.CO, Jakarta - A team of students from IPB University in Indonesia successfully utilized red onion skin, which is usually discarded, as the main ingredient for eco-friendly anti-acne sunscreen combined with seaweed.

The team consisted of Sinta Dewi Putri from the Department of Chemistry (as the head), Zahra Salsabila Hananingsih, Zahwa Sheillazara Fadhilah Ardi, Viola Andini Ferdian Putri, and Unzila Nisa Sajdah from the Department of Biochemistry. All five are students of the Faculty of Mathematics and Natural Sciences (FMIPA) participating in the Student Creativity Program (PKM) under the guidance of Syaefudin.

Sinta stated that red onion skin and seaweed are rich in bioactive compounds beneficial for skin health. These natural active compounds can work as antibacterial agents against Propionibacterium acnes, the cause of acne, while also providing antioxidant and anti-inflammatory effects.

"Red onion skin and seaweed contain phytochemical compounds such as flavonoids (quercetin, anthocyanin), tannins, as well as phenolic compounds that act as antioxidants and antibacterials," she said in a written statement on Wednesday, October 14, 2025.

Seaweed, in particular, is rich in bioactive compounds such as polysaccharides (alginate, carrageenan, agar), vitamins, minerals, as well as phenolic and terpenoid compounds that have proven antioxidant, anti-inflammatory, and antibacterial activities," she added.

The sunscreen product produced has several advantages compared to commercial products made from synthetic ingredients. In addition to utilizing organic waste from onion skin, the natural ingredients used are more environmentally friendly and have minimal side effects. "We are trying to offer a natural alternative, minimal side effects, and potentially safer for sensitive skin," said Sinta.

She mentioned that the combination of red onion skin and seaweed extracts has a synergistic effect. Based on literature, red onion extract can inhibit Propionibacterium acnes bacteria by 60-80 percent, while seaweed can do so by 40-70 percent, depending on the type and concentration of the extract. "If these two ingredients are combined, their effectiveness has the potential to exceed 80 percent," she stated.

In addition to being an antibacterial agent against acne, she explained that their bioactive contents also function as antioxidants to combat free radicals, as anti-inflammatories to reduce inflammation, while also maintaining skin moisture. This potential opens up significant opportunities for the use of local ingredients as the basis for multifunctional natural cosmetics.

"This product is suitable as a trend in green cosmetics because it is made from natural ingredients, environmentally friendly, and has a very wide market, especially among teenagers and young adults. Additionally, it has the potential to be developed as halal, organic, and local cosmetics," she added.

With this innovation, according to Sinta, her team has not only created added value from onion skin waste but has also presented a sustainable solution that supports the green cosmetic trend in Indonesia.

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