teak oil
I have asked the same question to our Sailing club member that is a retired wood shop teacher. He was telling me that many of the teak oils on the market are too watered down to do a good job. He told me to use Pure Tung Oil. you start by sanding off the weathered area of the Teak wood and wiping on the Pure Tung Oil. Let this first coat soak in (few days) and apply another coat. The Tung Oil I have is Behlen Master Pure Tung Oil (China Wood Oil), this oil contains no dryers or thinners. I hope that you are able to find this oil. Good sailing.
