Who We Are


“We want to create timeless, yet trendy garments; beautiful, yet ethical.”



About COSSAC & Agata

What began as an infatuation with the glamorous side of fashion quickly turned into a full blown love affair that enabled Agata Natalia Kozak to not only carve an industrious career in fashion design, but would lead her to pioneer industry change towards eco fashion. 

Agatka was born and raised in Poland, later moving to Barcelona to complete fashion study at ESDi and then to Istanbul to attend the prestigious Mimar Sinan. After successfully graduating from her fashion education, she moved to London, a city recognised as one of the world’s fashion epicentres.

In 2014, after working for both high end and high street labels and with some distinguished designers for LFW, and witnessing fast fashion’s destructive influence in the industry she loves, Agata decided to launch her ECO-HOT label, COSSAC. 

COSSAC promotes the minimalistic concept of Capsule Wardrobes, and offers a curated selection of contemporary threads and redefined basics with a sass edge. Sustainably designed and ethically produced, each quality garment is intended to be transeasonal, with the aim of minimising wastefulness and maximising usefulness.

An emerging eco fashion brand, COSSAC — and in fact, Agata herself — has already gained support from conscious fashion advocates and received mainstream coverage from publications including Vogue, Elle (Netherland), Glamour (Germany), C-Heads Magazine, Self Control Mag and Nylon.

As of February 2022, COSSAC partners with 52 passionate stockists globally, all of whom support the brand’s mission to create fashion with aesthetics and ethics.


Our Ethos

We are committed to slow fashion and sustainable design. Transparency, sustainability and social well-being is at the core of our business. We reject the mainstream practices of fast fashion that produces cheap, low-quality and disposable trend items by exploiting workers. COSSAC exists to offer women design-led conscious fashion to help drive awareness of the negative social and environmental impacts of the fashion industry and make it easy for women to make better choices.

We think sustainable fashion that no one wants to buy or wear is 100% wasteful. That’s why we design clothing that customers actually want to wear. The designs are contemporary with a sassy twist making them relevant to the modern woman. The silhouette celebrates the feminine form but is classic enough so that our garments are worn and cherished beyond the current season. Our production runs are limited to minimise waste and deadstock.

To help customers be part of the fashion revolution we’ve created a dictionary filled with useful terms which you can access here.


Business Practices

We make every effort to incorporate sustainability into every aspect of our business. All online store receipts, purchases and delivery details are communicated via email to reduce paper waste. All packaging and labelling is kept to an absolute minimum during deliveries. Our business cards, swing-tags and boxes are made from recycled paper and are 100% recyclable. We aim to leave no trace apart from the statement our customers make in our garments.

While we take the concepts of sustainability and the ethical treatment of garment workers seriously, we deal with all the heavy stuff so you won’t have to.