Medically reviewed by: Liudmila Zhaunova
Digital tools are playing an increasingly prominent role in how people manage their health, with nearly 50% of adults in the United States reporting the use of at least one health-related app. With more than 350,000 health apps available globally, these tools now play a significant role in how individuals monitor their symptoms, access health information, and support their overall well-being.
Despite this widespread uptake, the level of scientific evidence supporting many health and wellness apps varies considerably. To better understand the current evaluation landscape, Flo’s science team conducted a scoping review of published studies assessing the effectiveness of consumer health apps. The review identified substantial variation in study design and a marked lack of demographic diversity among research participants, highlighting the absence of standardized approaches to evaluating digital health interventions.
These findings, published in BMC Digital Health, contribute to the growing discussion around evidence requirements and best practices for assessing consumer-facing digital health tools.
Most consumer health and wellness apps, including those focused on fitness, nutrition, mental well-being, and sleep, are not subject to regulatory oversight by health authorities such as the United States Food and Drug Administration (FDA). Only apps developed for medical purposes require approval and regulation by the FDA and other health authorities in their respective countries.
In the absence of a formal regulatory framework, the level of scientific evidence generated by developers varies considerably. While clinical care is guided by evidence-based standards, there are currently no equivalent requirements for the majority of consumer digital health applications. This contributes to a heterogeneous evidence landscape, in which evaluation methods, outcome measures, and reporting practices are often inconsistent.
“There are hundreds of thousands of health apps on the market — whether you’re using a wellness app to track your fitness or nutrition or an app to manage a health condition — but only a tiny fraction of these have actually been proven to work in scientific studies,” Liudmila Zhaunova, PhD, director of science at Flo, commented on the team’s research.
To better understand this landscape, Flo’s science team conducted a scoping review of published evaluations of mobile health apps. The initial search identified 2,799 publications, of which 739 were screened in detail. These studies represented a range of app types (both consumer-facing and clinician-facing) and a variety of research methodologies.
Focusing specifically on studies evaluating apps with at least 50,000 downloads and assessing health or well-being outcomes, the team identified 47 relevant studies published in scientific journals over the past five years. Although this represents a small fraction of the overall market, it demonstrates that meaningful and rigorous research is feasible in the consumer digital health space.
It was also encouraging to see that companies at various stages of development were conducting scientific studies, including start-ups and scale-ups that had undertaken scientific evaluations of their products. This suggests a growing recognition within the sector of the importance of generating robust evidence to support digital health interventions.
Of the 47 studies, 30 were randomized controlled trials (RCTs), the most robust approach for determining whether an intervention produces measurable benefit. The existence of multiple RCTs indicates that some developers are investing in high-quality evaluation, despite the lack of regulatory requirements mandating this level of evidence.
“RCTs are the gold standard of testing how well an intervention works, whether that’s a new drug, vaccine, or a health app. We were pleasantly surprised to find that among the studies testing health apps in the past five years, there were quite a few RCTs,” Carley Prentice, MPH, lead study author, explained.
“This is encouraging, as it shows that developers who do put their apps to the test are willing to use rigorous and high-standard study designs,” Carley continued.
Flo’s science team has also undertaken an RCT evaluation to assess our app’s impact. You can read more about what we found here.
Next, our team examined the demographic characteristics of participants in the scientific trials. Here, we found that 29 of the 47 studies were conducted in the United States, while the remainder were conducted in 14 other countries worldwide.
Ethnicity was only reported in 27 of the 47 studies. Of these, four apps were designed for specific populations. Across the remaining studies, participant representation was limited, with average distributions of:
These findings highlight a significant lack of demographic diversity in many evaluations of consumer health apps, raising concerns about the generalizability of results to broader populations.
“It’s important that scientists who investigate how well an app works recruit a diverse group of participants for their studies. Diversity in recruitment is a challenge in many studies, but it’s something that we need to actively work toward,” Liudmila pointed out. “Inclusivity and equitable access to health apps should be everyone’s goal, and research needs to reflect this.”
The findings from this review underscore what the authors describe as an emerging “evaluation crisis”: the majority of consumer health and wellness apps are released with limited evidence to demonstrate meaningful benefit. This gap underscores the need for more consistent and rigorous evaluation approaches to digital health tools before they are introduced to the public.
“Looking at the evidence, we see that it is, in fact, possible for health and wellness app companies to run RCTs, even with smaller sample sizes and shorter durations. However, for developers looking for a simpler and more cost-effective approach, pre/post studies offer a solid starting point that still provides valuable insights,” Carley said.
In light of the lack of guidelines and standardized best practices for wellness health app developers, the team also hopes to provide the beginnings of a blueprint for other companies to incorporate robust science into their product development.
At Flo, we’re committed to evidence-based care. Discover the studies and data that inform our app’s development at Flo Science and Research.