Green Tea Extract and Tea Seed Oil

There are plenty of things that evoke Kyoto in people's minds, but very few of them can actually go into a cosmetic product.

Among them, KOTOSHINA turned its attention to "Uji tea."

Tea has long been familiar to people not just as something to drink, but as something genuinely good for the body — already used in things like soap and face masks — making it something people would readily accept.

That idea became the starting point for KOTOSHINA's tea-based product development.

● Why Tea Seed Oil Is So Rare

Oil is an essential ingredient in cosmetics.

"Tea seed oil" is extracted from the seeds of the tea plant, harvested after the tea flowers have bloomed.

A tea farm's main job is growing high-quality tea leaves, but when tea flowers and seeds form, nutrients get diverted toward them, making it harder for nutrients to reach the leaves themselves. Tea plants are also typically propagated through cuttings rather than seeds, so farms have no real need to collect them. For these reasons, tea flowers and seeds have traditionally been considered unnecessary by-products for tea farms.

What's more, a double handful of tea seeds yields only a few drops of oil. To turn tea seed oil into an actual product, we needed the tea farm to specially produce a much larger quantity of tea seeds than usual.

For KOTOSHINA's skincare products, we were determined to use this organically grown tea seed specifically. We wanted this exceptional oil to deliver both a sense of Kyoto and genuine peace of mind.

The first step toward that goal was finding a tea farm willing to work with us.

Uji, Kyoto, a renowned tea-producing region, has many tea farms — but few of them practice organic cultivation and are also willing to collaborate on cosmetic development.

After visiting numerous farms, we finally found one certified under Japan's organic JAS standards, dedicated to producing safe, trustworthy tea without pesticides or chemical fertilizers.

KOTOSHINA's tea seed oil is a rare organic oil, born from that very commitment.

● Developing Organic Cosmetics Around Tea Seed Oil

The "green tea ingredients" and "tea seed oil" used by KOTOSHINA are grown in natural soil that has, as a general rule, been free of pesticides and chemical fertilizers for at least three years. The tea leaves are grown slowly over four to five years, resulting in green tea ingredients and tea seed oil rich in natural nutrients and vitality.

While "tea seed oil" isn't widely known, it turned out to be a remarkably excellent ingredient — almost as if it were made specifically for beauty and health.

● The Benefits of Tea Seed Oil — Wonderful Whether Eaten or Applied

While tea seed oil isn't widely known in Japan, in neighboring Taiwan it's called "cha-yu" and is a beloved, healthy cooking oil. Its defining feature is an oleic acid content of over 80%.

Given that olive oil typically contains around 50–80% oleic acid, tea seed oil actually contains even more. It's also rich in other beneficial components, including catechins (well known for their presence in green tea), coenzyme Q10, and vitamin E — all valued for beauty and health. And just like camellia oil, it offers excellent moisturizing power.