Signos Sells a Continuous Glucose Monitor, But Not to Diabetics

Signos is asking customers to pay for the privilege of testing their glucose monitoring system.

You may have seen the commercials for FreeStyle Libre devices. Continuous glucose monitors (CGMs) are intended to help improve management of diabetes in patients whose diabetes is not under good control, and also for patients who hate having to keep pricking their finger for blood tests. A small, wearable sensor samples levels of blood glucose in the interstitial fluid (a proxy for blood glucose levels) at frequent intervals. The results can be read on a smart phone. It can alert patients to spikes or drops in the glucose levels, and it can help patients understand how diet, exercise, stress, sleep, and other factors affect blood glucose levels, so they can make appropriate adjustments to their diet and lifestyle.

Now there’s a new kid on the block, Signos. It sells a system with a continuous glucose monitor and support. But it’s not for diabetes. In fact, if you have diabetes you are ineligible. They are selling it for weight loss! And for energy and general health. They advertise: “Discover how your body responds to what you eat, and make small changes to hit your health goals”.

A prescription is required. Signos will help you get a prescription based on your answers to an online questionnaire. The Signos app will provide suggestions and online support.

Annoying and deceptive marketing practices

There is a button on the home page of their website to “request access.” You must answer a series of personal questions and you are warned that there is a long waiting list.

I answered the questions to see what would happen. I was then asked to choose my plan: 6 months for $149 a month, 3 months for $199 a month, or 1 month for @299 a month (marked down from $499 a month). All plans included “AI-powered weight loss insight, digital telehealth assessment, a best-in-class CGM for the duration, and FREE shipping”. The two longer-commitment plans also offered access to an in-app Nutritionist. When I chose the 6-month option, it said the 6-month subscription was $895 without a promo code. If there was a promo code, I didn’t see it. I didn’t subscribe. Shortly after I answered their questions, I received an email from Signos. It said “You’re in, Harriet! We’ve opened up 500 spots this week, so grab yours now. Your spot will be reserved for 72 hours.” A follow-up email arrived the next day, saying “Remember: We hold your spot for 72 hours. Time is ticking.”

The science behind Signos

A tab promises to reveal the latest scientific studies that show the effectiveness of Signos. It lists some studies that speculate about what they hope will be accomplished by Signos, but no studies that look at the actual effectiveness of the system. I thought the information they provided was deceptive, farcical, and insulting. They don’t have any evidence yet! They readily confess “Signos is in the process of conducting research on the feasibility of CGM use for weight loss”.

What that means is that they are hoping to recruit 20,000 customers to be their guinea pigs for a study that is registered in and is estimated to be completed by November 1, 2026. The stated purpose of the study is “to collect three years of CGM data to show how efficacious the Signos program is in helping people lose weight, improve body composition, and promote overall wellness”. That’s a misstatement. The data may show “IF” the Signos program helps people lose weight. But without an appropriate control group for comparison, it won’t even show that.

According to, “the Signos app will use CGM data to provide recommendations customized to users for promoting general health and wellness”. How can they provide customized recommendations if they don’t even know if the program works?

Conclusion: An untested system

They appear to have great hopes for the Signos program, but marketing Signos now is really jumping the gun. The hopes are not yet supported by any credible evidence, and they have the chutzpah to expect their customers to provide the evidence for them. And to pay for the privilege! I think that’s unconscionable.

This article was originally published in the Science-Based Medicine Blog.

Dr. Hall is a contributing editor to both Skeptic magazine and the Skeptical Inquirer. She is a weekly contributor to the Science-Based Medicine Blog and is one of its editors. She has also contributed to Quackwatch and to a number of other respected journals and publications. She is the author of Women Aren’t Supposed to Fly: The Memoirs of a Female Flight Surgeon and co-author of the textbook, Consumer Health: A Guide to Intelligent Decisions.

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