Semglee or Rezvoglar vs. Lantus Insulin Pens

Those of you using either Semglee or Rezvoglar long-acting insulin, what have been your experiences?
Compared to Lantus?? I may have to switch from my tried-and-true Lantus SoloStar pen due to supply shortage, and wonder which would be the best alternative…

I don’t have any experience with either Semglee or Rezvoglar but your post has taught me a new word in FDA regulation of insulin: interchangeable.

The Semglee website contained this note:

According to the FDA, an interchangeable product is a biological product that is approved based on data demonstrating that it is highly similar to an FDA-approved reference product and that there are no clinically meaningful differences between the products.

While I don’t discourage your continued due diligence, if it were me, I’d be tempted to just try one of these products and see what happens. Good luck! Please let us know what happens.

Edited to add: Doing a quick search for product reviews revealed a possible reason why you posted. The reviews are poor, to say the least. Sometimes the internet skews things as review sites are dominated by the bad reviews and the happy users are enjoying life and don’t post. Is there any way that you could get a sample from your doctor?

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There are certainly people who post all kinds of misinformation on the internet, including that generic medications of whatever type are different. I have never found it to be the case, and happily just switched from Novolog to generic Insulin Aspart.

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We are in a new era of biosimilar and biointerchangable insulin. This issue is being felt in many different disease communities, and insulin will be the next but not likely the last biosimilar product.

So, let me start by saying I have advocated biosimilar medications. I have done this in inflammatory arthritis. I am not paid and have fully divested my stock in all pharma.

Ok, so what are biosimilars? Insulin, like all biologic-based medications, is not merely a group of chemicals put together for an outcome. It is instead a living biologic compound. It is made in labs, much like dough made in the kitchen. It starts with living yeast; one adds the right ingredients, and at a certain point, you have dough.

It is a similar process to human insulin. No, it does not start with yeast; rather, it begins with living material that produces a compound that today we call insulin.

Biosimilar insulin is the mixing of similar compounds together in a similar process that produces a similar effect.

So why are these new compounds called generic medications? Because they are not exactly the same. Nor could they ever be. Remember, these are living compounds. Recognizing this, the FDA and the European Union agreed to call them a new class of medication. They are called Biosimilar and Biointerchangable. All insulin products are biosimilar, so I will focus on them for the time being.

What do biosimilars do? They should produce the same impact similarly and hopefully for less money. The promise of less money caused me to embrace the products.

How long have they been around? These products have been used in Europe for over 12 years. Insulin was not the first medication to be done, and it will not be the last.

So why now? Manufacturers kept biosimilar medications out of the US by making minor refinements to the reference product. (The reference product is name brand).

So, are biosimilars the same as the reference? No, but they are functionally equivalent. To come to market, they have to prove they act in the same manner as the reference product.

Who makes biosimilars? Lilly makes Rezvoglar. Other big names in the market are Pfizer, Johnson and Johnson, and other big manufacturers. But also subsidies. Unilever owns Biocon, which makes Semglee. Again, these are not fly-by-night companies.

In the future, almost all biologic medications will be made similar. While these medications are not generic, they are substantially the same.

Check out more at

Note that in 2021, I asked to switch to a biosimilar to treat RA. I did so despite advice from my rheumatologist because I feel so strongly that it is important to support biosimilar development.