When a biochemical corporation manufactures implants that help millions live longer, they go from pariah to savior. But a longstanding critic remains unconvinced, and must battle the corporation and its backers to uncover the shocking secret behind the technology.

Thanks all, as usual the feedback has greatly helped to clarify my thinking. I agree that the weakness of the original logline was not coming to the key conflict/story until the second sentence - the first sentence really gave backstory. So agree with a reworking along the lines Tor set out. Here's an attempt, let me know any further thoughts, thanks:

"An outsider scientist uncovers a shocking secret behind a biochemical implant that helps millions live longer and now must expose his findings before the corporation silences him.?

This sounds really good. It needs to have a little more conflict though. What stands in his way? Just investigating a biochemical company is interesting but you have to make it interesting enough for people to pay money to see it.

p.s.

In the example I provided, you could replace "corporation" for "manufacturer".

"A (weakness & occupation)** uncovers a shocking secret behind a biochemical implant that help millions live longer and now must expose his findings before the corporation silences (him//her)**."

Hope this helps :D

As I am reading more log lines, I find that is is very important to get your point across in as fewer words as possible. From an outside view, I believe that is possible with what you have already written here.