Lilly Diabetes – Making Insulin

VialPackagingLineI can cross “tour an insulin manufacturing facility” off my bucket list.

It was absolutely mind-blowing.

There is a lot of science involved, much of which I am not quite bright enough to understand. But the basic idea is that they start with some E. coli bacteria that is modified to produce insulin as it grows, then it is harvested, the insulin is stripped out, purified, packaged up and delivered to us.

One of the best places I could find that talks about how cells work actually used insulin as an example of biotechnology. From an article at

To create insulin inexpensively, the gene that produces human insulin was added to the genes in a normal E. coli bacteria. Once the gene was in place, the normal cellular machinery produced it just like any other enzyme. By culturing large quantities of the modified bacteria and then killing and opening them, the insulin could be extracted, purified and used very inexpensively.

That makes it sound so simple, and I find it ironic that they used the word “inexpensively” more than once. There was nothing inexpensive about what I saw. Maybe it’s a relative term? Comparing it to the process of killing cows and pigs and harvesting insulin from their pancreases? On that note, I had trouble picturing the land we were visiting being a large slaughterhouse no more than thirty years ago.

I also learned that the first insulin made using this method of inserting human genetic instructions into a bacterium at Lilly was made possible through a partnership with Genentech (now owned by Roche).

Big and Small

I couldn’t wrap my brain around the quantities involved, so I’m going to describe it using  very general ideas.

InsulinHexamerImagine growing grass on a field the size of a few football fields. You start with nothing but space. You get the soil and prepare it, plant the proper seeds, then nurture the growing seeds until they’ve grown up into tall stalks of grass. But only a tiny portion of that grass stalk is the part you need. Imagine the entire grass stalk representing 100%, but you only need the 33% piece and 35% piece. The rest is useless to you (but you wouldn’t have those two specific parts without the whole).
Now you harvest each blade of grass and separate the parts you need from the parts you don’t. Then within that 33% piece and 35% piece there are impurities which need to be stripped off and discarded, but that purification process costs you some expensive chemicals and a ton of time.
After a couple of months and three football fields of grass, you end up with a finished batch of product that can fit in your briefcase.
You can run the whole process again, but don’t forget that your soil is only good for a limited number of growths before it too needs to be discarded and replaced.
It’s an incredibly complicated and expensive process. Getting us to appreciate the cost and complexity was surely the main idea behind the tour.
I’m convinced. I appreciate it.

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8 Comments on "Lilly Diabetes – Making Insulin"

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Tavia Vital

Nice post and subsequent comments. I sometimes find it devastating the cost of meds for diabetes. This post helps us understand part of the “why”.
Did you know that Eli Lily sent a letter in the early days of insulin production apologizing for the increases in pricing? I find that thought touching.

Richard Vaughn

There is a company that has produced an injectable form of c-peptide. Read about it below. It has been shown to be effective in trials with human subjects. I hope it will eventually become available to type 1 diabetics.


Fascinating stuff Scott – thanks for posting all this information.

Thanks Scott. My post on the insulin production topic is in the process of fermenting, i.e. I need to go re-read it. I think you are far more sophisticated in your piece here than I will be. Thanks for that since I compare making insulin to brewing beer. C-peptide, as Scott mentioned, was a topic of a side conversation with David Kendall, MD, Medical Affairs, Lilly Diabetes (his card also says, “Distinguished Medical Fellow”), Scott, George and I. Before getting into this too deeply it is important for me to point out that I am not a Dr., a biologist,… Read more »
Scott E

Wow, Scott… thanks for your easy-to-comprehend (yet oh, so difficult to understand) description! I always wondered how they mass-produce this stuff; it’s not like growing just one unit of insulin in a petri dish in a lab!