Experts question the promise of digital menstrual tracking
Menstrual tracking apps and the broader category of "femtech" products are marketed aggressively to women and girls, both through social media promotion and by technology companies themselves. These tools often claim to analyze personal data scientifically in order to improve health, well-being and physical performance based on where a user sits in her menstrual cycle. But a newly published analysis in The BMJ argues that the evidence underpinning those promises is far weaker than the marketing suggests — and that the risks may outweigh whatever benefits exist.
The commentary comes from Katharine Lee and colleagues, who contend that digital menstrual tracking, along with the increasingly popular practice known as cycle syncing, requires "critical interrogation and resistance." Their central claim is straightforward: neither menstrual tracking nor cycle syncing has been convincingly shown to improve health outcomes or measures of performance. The BMJ, a peer-reviewed medical journal, published the analysis as part of its ongoing coverage of women's health research.
What cycle syncing actually claims
Cycle syncing refers to the practice of adjusting diet, exercise and daily habits according to the phases of the menstrual cycle. Proponents present it as a way to work with the body's natural hormonal rhythms rather than against them, and the idea has spread widely through wellness content online. The authors acknowledge that the concept is appealing — it offers a personalized-sounding framework for nutrition and training — but they argue that the scientific support is thin.
According to the analysis, research on phase-based dietary interventions, whether aimed at reducing menstrual symptoms or boosting performance, is generally inconclusive. Where findings do exist, they tend to be highly individualized or speculative. In other words, any signal that appears in the data is not strong or consistent enough to justify the confident claims made by app developers, coaches and influencers who promote the practice.
Decades of sports science point the other way
The commentary leans heavily on sports science research accumulated over many decades, which the authors say shows no overall effect of menstrual cycle phase on athletic performance, injury risk or general health. Any effects that researchers have identified are described as trivial and highly individualized, meaning they vary enormously from one person to the next rather than following a predictable pattern that could be applied across a population.
That distinction matters. A population-level trend that is essentially absent cannot easily be translated into individual guidance, and the authors suggest that the small, person-specific variations that do show up are precisely the kind of thing that generic digital tools are poorly equipped to capture. The result is a gap between what the science supports and what the products promise.
The prediction problem
Even if menstrual phase did correspond to meaningful fluctuations in health, performance or vulnerability to injury for a given individual, the authors explain that simple digital tracking technologies cannot reliably predict such variation. The reasoning is that tracking tools depend on self-reported data, estimates and algorithms that do not have the resolution or the validation needed to forecast a person's physiological state on a given day.
This is a critical point in the argument. Many apps present their insights as scientific analysis of personal data, a framing that implies a level of precision the underlying methods may not deliver. When users act on those insights — changing training loads, altering nutrition, or interpreting symptoms through the lens of a predicted phase — they may be responding to patterns that were never firmly established in the first place.
Beyond weak evidence: the risks of tracking
The authors are careful to note that their concerns extend past the shaky evidence base. Digital cycle tracking technologies, they write, also carry serious risks of their own. Among the harms identified in the analysis:
- Wasted time and labor, as users invest effort in logging, interpreting and acting on data of uncertain value
- Unwanted surveillance, including the possibility that tracking data is accessed or used by parties the user never intended
- Threats to the privacy of sensitive reproductive health data, which is among the most personal information a person can generate
- Distraction from — or even outright threats to — broader efforts to advance women's health, as resources and attention flow toward commercial products with unproven benefits
The privacy concern is especially notable given how intimate the data is. Menstrual and reproductive information can reveal a great deal about a person's body and life circumstances, and once that information leaves a user's device, control over it becomes difficult to recover. The authors frame these vulnerabilities as a structural feature of the consumer technology landscape rather than an unfortunate side effect.
The stakes for women's health
In the analysis, Lee and colleagues warn that the scale of adoption makes these issues consequential. "These apps have the potential for widespread impact on the well-being of women and girls," they write, adding that the evidence these digital tools can actually help manage menstrual conditions, boost health, or provide meaningful insight into exercise and nutritional needs is lacking.
That combination — enormous reach paired with limited proof — is what makes the marketing so important to examine. When products are promoted directly to young users through social platforms, the persuasive power of polished interfaces and confident health claims can outpace the underlying science. The authors argue that this dynamic deserves resistance, not passive acceptance, from researchers, clinicians and consumers alike.
What the experts recommend
Rather than simply cataloguing problems, the commentary outlines steps that could reduce the risks associated with digital menstrual tracking. These suggestions include:
- Strengthening legal and regulatory protections for consumer and employee data, so that reproductive health information is not easily exploited or exposed
- Improving user awareness of how tracking data is collected, shared and used, giving people a clearer picture of what they are handing over
- Guiding clinicians on how and when to recommend apps to patients, so that medical advice does not default to commercial tools with uncertain evidence
The through-line across these recommendations is transparency and caution. Users should know what they are signing up for, employers and platforms should face firmer limits on how they handle sensitive data, and health professionals should be equipped to distinguish between well-supported interventions and products that are simply well marketed.
A call for skepticism, not dismissal
The analysis does not claim that every tracking tool is worthless or that cycle awareness has no place in health care. Instead, it argues that the burden of proof has not been met, and that the enthusiasm surrounding femtech has run ahead of the evidence. Menstrual cycle research remains an underfunded area, and the authors suggest that genuine progress in women's health is more likely to come from rigorous study than from subscription features.
For now, the practical takeaway for consumers is a familiar one: a sleek interface and a scientific-sounding claim are not substitutes for demonstrated benefit. The authors' call for scrutiny is aimed at everyone in the chain — developers who design the algorithms, platforms that host the advertising, regulators who set the rules, and clinicians who field questions from patients — because the potential consequences touch the daily lives of a very large population of women and girls.
This article is based on reporting by Medical Xpress. Read the original article.
Originally published on medicalxpress.com
