Glucose monitors are the new wellness accessory. 23 studies ask who actually benefits.
A meta-analysis of continuous glucose monitors in people without diabetes found a real effect on blood sugar — but only in those with prediabetes. In healthy users, the evidence for a metabolic benefit was not there.
Continuous glucose monitors, once a tool reserved for people with diabetes, are now sold directly to anyone curious about their blood sugar between meals. A systematic review and meta-analysis published in the European Journal of Medical Research this year set out to check what the evidence actually supports when a CGM is worn by someone who doesn't have diabetes — and it found the answer depends heavily on who's wearing it [s1].
What the review looked at
The researchers pooled 23 studies covering 1,074 participants across 11 countries who did not have diabetes: seven randomized controlled trials, one cohort study, seven prospective observational studies, four cross-sectional studies, and four additional clinical trials [s1]. The search covered the PubMed, Cochrane, Web of Science, and Embase databases for studies published through December 2025 [s1]. Most of the studies were aimed at one or more of four goals: optimizing glycemic control (39% of studies), managing weight (39%), modifying dietary behavior (52%), or improving adherence to a health intervention (22%) [s1].
The finding: it depends on baseline metabolic health
Pooled across all participants, CGM use was associated with a statistically significant improvement in mean blood glucose compared with people using conventional monitoring or no monitoring (standardized mean difference of -0.54, 95% confidence interval -1.02 to -0.07, P = 0.03) [s1]. But the review's more specific finding is the one that matters for the wellness-wearable pitch: CGM meaningfully improved glycemic control specifically in people with prediabetes, while no appreciable glycemic benefit showed up in people who were already healthy and normoglycemic [s1].
On two other measures commonly implied by marketing around these devices, the evidence was thinner. There was no significant difference in body mass index between CGM users and controls (SMD -0.25, 95% CI -0.63 to 0.12, P = 0.19) [s1]. And on measurement accuracy — how closely CGM readings track a reference blood glucose measurement — there was no significant difference reported either (mean difference -3.90 mg/dL, P = 0.40) [s1].
Where the review did find a consistent signal was behavioral: CGM use was associated with higher adherence to whatever intervention it was paired with, and with specific changes in dietary behavior, though the review describes the effect on broader glycemic variability metrics as "context-dependent" rather than uniform [s1].
What this means for the healthy person wearing one
The pitch behind consumer CGM products — patches that let anyone watch a real-time glucose graph on their phone — generally implies that seeing your own glucose curve will translate into better metabolic health, whatever your starting point. This review is a caution against that implied leap. The people who benefited from CGM in the pooled data were the ones who had a metabolic problem to correct: those with prediabetes. For someone who is already normoglycemic, the review found no appreciable glycemic benefit, and no significant effect on weight [s1].
That doesn't mean CGM is useless for the metabolically healthy — the review notes real value on the behavioral side, where wearing a monitor and seeing the data seemed to help people stick with a dietary or lifestyle change more consistently than they otherwise might [s1]. Whether that adherence effect, on its own, justifies wearing a monitor with no metabolic disease to manage is a judgment call the evidence doesn't settle either way.
The limits of what's known
The review's own dataset is modest — 1,074 total participants across 23 studies, most of them short trials rather than long-term follow-ups. The authors are explicit that evidence on hard, longer-term outcomes remains limited, and they call for larger, longer trials before CGM-guided lifestyle interventions in non-diabetic populations can be considered a settled, cost-effective strategy [s1]. For now, the honest summary is narrower than the marketing: a real signal in people who already have abnormal glucose regulation, and an open question for everyone else.
Sources
- Continuous glucose monitoring in non-diabetic populations: a systematic review of observational and interventional studies with meta-analysis — European Journal of Medical Research , January 26, 2026
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