- In a UK study of 57,975 adults on semaglutide or tirzepatide, people who engaged with the program's app lost 11.53% of their weight by month 5, vs 8% for those who didn't.1 That gap is where the "44% more" claim seen in several apps comes from.
- A 2026 Australian study of 6,113 adults found that, of all app features, only progress logging was consistently linked to faster weight loss.2
- All of these studies are observational and were run with, or by, the companies involved. They show a link, not proof that the app caused the extra loss.
Why this question matters
Keeping a record of what you eat, how you move and what you weigh is the oldest tool in weight management. A 2011 systematic review of 22 studies found a significant link between self-monitoring and weight loss in every type it looked at: diet, exercise and self-weighing. It also rated the evidence as weak, because most studies relied on self-report and enrolled mostly white women.4
GLP-1 medicines changed the picture. They lower appetite directly, so it is fair to ask whether tracking still adds anything. Three recent studies looked at exactly that in people taking semaglutide or tirzepatide through online weight-loss services.
Study 1: 57,975 people in the UK (2025)
Researchers analyzed adults aged 18 to 75 who started semaglutide or tirzepatide through Voy, a UK digital weight-loss service, between February 2023 and August 2024. Everyone had a BMI of at least 30, or at least 27.5 with a weight-related condition.1 People counted as "engaged" if they attended coaching, used the app often and tracked their weight regularly. About 54% met that bar.
Engaged people were also more likely to reach 5%, 10% and 15% weight loss at each time point.1 Note that "engaged" bundled coaching, app use and weighing together, so the study cannot say which of those mattered. Three of the six authors work for the company.
Study 2: 6,113 people in Australia (2026)
Published on November 3, 2026, this study followed adults in a direct-to-consumer program who received semaglutide or tirzepatide, with an optional smartphone app and clinician support.2 It compared people who used the app with people on medication only, and adjusted for medicine, age, gender, ethnicity and starting BMI.
| Weight-loss threshold | App users vs medication only (adjusted odds) |
|---|---|
| At least 5% | 1.38 to 2.22 times as likely, across days 60, 120 and 180 |
| At least 10% | 1.67 to 1.97 times as likely, by days 120 and 180 |
| At least 15% | 1.99 times as likely, by day 180 |
The more useful finding is about features. Of everything in the app, only progress logging was consistently linked to a faster weight-loss trajectory: about 0.26 percentage points more weight lost per 30 days. No other feature showed a consistent link.2 The authors describe the overall differences in trajectory as modest and say the results are not causal. The company that ran the program provided the data.
Study 3: 9,470 people on tirzepatide in the UK (2026)
This study grouped people by how they used a British digital weight-loss service: app logins, messages to a health coach, messages to an automated assistant, and weight tracking.3 It only included people who stayed on tirzepatide and reported a 6-month weight, out of 39,220 who started.
| Engagement pattern | Extra weight loss at 6 months vs low engagement |
|---|---|
| High health coach messaging | 4.60 percentage points |
| High automated assistant messaging | 4.69 percentage points |
| Passive self-trackers | 3.71 percentage points |
The authors say plainly that the design rules out causal conclusions. Two authors are paid by the company that runs the service.
What these studies can and can't tell you
- They show a link, not a cause. People who choose to log may already be more motivated, have fewer side effects or stay on their medicine longer. Each study adjusted for some of this, but not all of it can be measured.
- They studied full programs. The apps came with prescribers and, often, coaching. A standalone tracker you download yourself has not been studied in the same way.
- The companies were involved. All three used company data, and two have company staff as authors. That doesn't make them wrong, but it is worth knowing.
- There is no randomized trial yet of a tracking app added to GLP-1 treatment. Until there is, "trackers lose 44% more" is a correlation, not a promise.
What the evidence does support is modest and practical. Regularly recording your weight goes with better results, in older diet research and in people on GLP-1 medicines. Logging doses and side effects has other uses that don't depend on weight: not missing a dose, seeing whether nausea follows a dose increase, and bringing real numbers to appointments. Protein matters too while you lose weight; see how much protein on a GLP-1.
If you are choosing an app, our comparison of GLP-1 tracker apps lists what each one offers and what it costs.
Common questions
Where does the "trackers lose 44% more" claim come from?
From a 2025 study of 57,975 UK adults on semaglutide or tirzepatide in the Voy program. At month 5, engaged users had lost 11.53% of their weight and non-engaged users 8%. 11.53 is about 44% more than 8. The study was observational and run by the company.
Does using a GLP-1 app cause more weight loss?
Not proven. Every GLP-1 study so far is observational: people who chose to engage lost more, but they may differ in other ways. No randomized trial has tested a tracking app alongside these medicines.
What is the most useful thing to log on a GLP-1 medicine?
In a 2026 study of 6,113 adults, progress logging was the only app feature consistently linked to faster weight loss. Doses, side effects and protein matter for other reasons: reminders, spotting patterns and talking to your care team.
Sources
- Johnson H, Huang D, Liu V, et al. Impact of Digital Engagement on Weight Loss Outcomes in Obesity Management Among Individuals Using GLP-1 and Dual GLP-1/GIP Receptor Agonist Therapy: Retrospective Cohort Service Evaluation Study. J Med Internet Res. 2025;27:e69466. PubMed · Full text (PMC)
- Davey B, Dabash O, Khanna R, et al. Digital Augmentation of Glucagon-Like Peptide-1 for Obesity Management: Retrospective Study. J Med Internet Res. 2026;28:e100728. PubMed · Full text (PMC)
- Talay L, Xu C, Hom J, et al. Digital Engagement Phenotypes and 6-Month Weight Loss in a Tirzepatide-Supported Digital Weight-Loss Program: A Retrospective Cohort Study. Medicina (Kaunas). 2026;62(9):1647. PubMed · Full text (PMC)
- Burke LE, Wang J, Sevick MA. Self-monitoring in weight loss: a systematic review of the literature. J Am Diet Assoc. 2011;111(1):92-102. PubMed · Full text (PMC)
