Former After School member Kahi loses trademark battle over ‘KAHI’ name, but can still use her stage name

Former After School member Kahi has officially lost a trademark dispute against the Korean cosmetics brand KAHI, following a legal battle over the use of the name for dietary supplement products.

However, the court's decision does not prevent the singer from continuing to use Kahi as her stage name in the entertainment industry.

According to legal industry reports on October 19, the trademark dispute between Kahi and the cosmetics company has ended, with the singer's trademark registration for dietary supplements declared invalid.

The legal disagreement began after Kahi applied to register KAHI, the English spelling of her stage name, as a trademark for dietary supplement products in 2021.

Her trademark registration was completed in 2023, allowing her to claim rights to the name for that particular product category.

However, the cosmetics brand KAHI challenged the registration, arguing that the singer's trademark was too similar to its existing brand name.

The company claimed that using the same name for dietary supplements could confuse consumers, particularly because cosmetics and dietary supplements are products that may be marketed to similar customers.

Kahi disagreed with the company's position, explaining that she had been using the name professionally long before the cosmetics brand entered the market.

The singer argued that her established history as an entertainer should be considered when determining whether she could register the name for her own products.

Despite her argument, the Patent Court ruled in favor of the cosmetics company.

The court considered several factors, including the relationship between cosmetics and dietary supplements, as well as the existing brand recognition of the cosmetics company.

Based on those considerations, the court concluded that Kahi's trademark registration for dietary supplements should be invalidated.

Kahi initially appealed the ruling but later withdrew her appeal.

As a result, the decision became final on May 20, 2026, officially invalidating her registered KAHI trademark for dietary supplement products.

While the ruling represents a legal defeat for the singer, its scope is limited to trademark rights involving the disputed product category.

Importantly, the decision does not mean that Kahi has lost the right to use the name she has been known by throughout her entertainment career.

She remains free to continue using Kahi as her professional stage name for singing, television appearances, and other entertainment activities.

The distinction is important because trademark registration for commercial products is a separate legal matter from an entertainer's professional identity.

Kahi made her debut as a member of After School in 2009 and later continued her career as a solo singer and television personality.

Her long-standing use of the stage name was one of the arguments raised during the legal proceedings, although it was not enough to overturn the cosmetics company's challenge to the product trademark.

The final ruling means Kahi cannot rely on the invalidated trademark registration to claim rights to the name for dietary supplements, but her entertainment career and stage name remain unaffected.

The case highlights how trademark disputes can arise when a celebrity's professional name overlaps with an existing commercial brand, particularly when both seek legal protection for related products.