I wonder if it's patent law that's keeping them secretive. There's a good chance they're trying to reverse engineer the insulin and concerned they may be infringing on manufacturing process patents etc. Once they've got a working formula it'd be easier to change it up to avoid these patents. Big pharma is notoriously litigious and I can see them taking any opportunity to nip this in the bud.

> I wonder if it's patent law that's keeping them secretive

Many insulin forms are no longer patented. Last year patents (at least in Europe) expired from some quick acting insulin variants and as a result insurers here are forcing everyone to cheaper generics. Side effect: Not all have the same solutions, though the insulin is the same. Despite what the insurers say, YMMV if you switch due to different solutions being present.

So I do not think patents on the product is a real issue. Maybe patents on the production method.

> cheaper generics

Interestingly, they're really not much cheaper, either. On the order of 10% cheaper, I believe.

There's a research exemption to patent law in the US, but that might not apply if they're publishing the details with a how-to manual.