Dexcom Stelo vs Oura Ring Gen 4
Two devices, the same questions: what does it actually measure, how good is the data, what does it cost to keep using, and who is it for.
Dexcom Stelo
The first over-the-counter continuous glucose monitor in the US. A 15-day skin-worn sensor that turns a black-box variable — your glucose response to food, stress and sleep — into a graph you can act on.
Full review →Oura Ring Gen 4
The best-in-class passive sleep and HRV tracker. A titanium ring you forget you're wearing that produces some of the most defensible sleep-stage and readiness data on the consumer market.
Full review →| Spec | Dexcom Stelo | Oura Ring Gen 4 |
|---|---|---|
| Price | Not sold in the UK — Abbott Lingo is the equivalent here, around £120/month | Around £350, plus roughly £6/month membership |
| Subscription | None (device is single-use) | Required after 1-month trial for full metrics |
| Form factor | Skin-worn sensor, upper arm, 15 days per sensor | Titanium ring, 7 sizes |
| Battery life | Sensor lifespan 15 days | 7 days |
| Water resistance | Yes (shower/swim) | 100 m |
| Platforms | iOS, Android | Same |
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| Metrics tracked |
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| Data quality | MARD (mean absolute relative difference) in the ~10% range vs venous blood glucose — best-in-class for consumer CGM. Interstitial lag makes rapid spikes appear ~5 minutes late. | Sleep-stage agreement with polysomnography is in the 79–80% range for prior generations — better than most wrist wearables. HRV and RHR trends are highly reliable when compared over weeks. Absolute values are calibrated to personal baselines, so cross-device comparisons are less meaningful than trend. |
| Ecosystem | Native Stelo app; data export to Apple Health and Google Health Connect. Third-party integrations via Dexcom API and platforms like Levels, Nutrisense and Signos. | Native app on iOS and Android. Exports to Apple Health and Google Health Connect. Third-party integrations via Zapier and the Oura API for developers. |
| Privacy | Glucose data stored in Dexcom cloud; can be exported as CSV. HIPAA-aligned handling. | Data stored on Oura servers with pseudonymised IDs; GDPR/HIPAA options available. Users can request full data export and account deletion. |
Dexcom Stelo
- Otc — no prescription needed for non-diabetics in the US
- 15-day wear, waterproof, minimally invasive
- Turns diet and exercise into an immediate feedback loop
- Best-in-class sensor accuracy in the CGM space
- Not intended for insulin-dependent diabetics (see G7 for that)
- 15-minute readings vs 1-minute on G7 — smoother, less real-time
- Interstitial fluid lags blood glucose by 5–10 minutes
- Metabolic-optimisation users identifying personal glycaemic responses
- Anyone with pre-diabetes or a family history of type 2 diabetes
- People chasing zone-2 fitness or GLP-1 protocol optimisation
- Type 1 diabetics needing dosing decisions from the device
- Users unwilling to wear a visible sensor on the arm
Oura Ring Gen 4
- Sleep-stage classification validated against polysomnography with reasonable agreement
- Passive, comfortable form factor — high adherence over months
- Excellent HRV trend data and readiness scoring
- Long-term temperature baseline detects illness onset early
- Membership is mandatory for full data — the ring alone is limited
- Poor for high-intensity exercise tracking (no GPS, no chest-strap accuracy)
- Screen-free — you must open the app to see anything
- Anyone whose primary goal is sleep and recovery optimisation
- Users who dislike wrist wearables or want a discreet device
- Longevity tracking of resting HR and HRV trends over months to years
- Serious endurance athletes needing real-time pace/GPS
- People unwilling to pay a monthly subscription
The lowest-friction way to turn glucose into an actionable metric. Non-diabetics should treat it as a 15–30 day learning tool, not a permanent wear.
If sleep and recovery are the metrics you care about most and you'll wear the device consistently, the Gen 4 remains the benchmark. Skip it only if you refuse subscriptions or need one device to also do serious training analytics.
Other comparisons
Scores reflect our own testing criteria — data quality, what the device measures that matters for healthspan, and total cost of ownership including subscription. Prices are manufacturer list prices and change often; check before buying. Some links are affiliate links, which never affect a score — see our affiliate disclosure.