Tool / wearable

Continuous Glucose Monitors (Stelo, Libre, Dexcom)

Last updated Sat May 30 2026 00:00:00 GMT+0000 (Coordinated Universal Time)

How they work

A small filament under the skin measures glucose in interstitial fluid every 1–5 minutes. The sensor lasts 10–15 days. Data flows to a smartphone app showing real-time values, trends, and time-in-range.

A ~10–15-minute lag exists between interstitial and blood glucose, which matters mainly during rapid changes (post-meal spikes, hypos).

Diabetes use

CGM has transformed type-1 diabetes management and increasingly type-2 diabetes (especially insulin-treated). Time-in-range (70–180 mg/dL) is now a primary outcome metric alongside HbA1c.

Non-diabetic / wellness use

The 2024 launch of OTC consumer CGMs (Stelo, Lingo) opened the market without prescription. Reasonable use cases:

Pre-diabetic adults wanting feedback on lifestyle changes.
Short-term n=1 experimentation with specific foods.
Pregnancy considerations.
Investigating unexplained energy/mood swings.

Less reasonable: indefinite continuous wear in metabolically healthy adults, who naturally see large normal glycaemic excursions that aren’t disease.

What matters operationally

Trend more useful than single values.
Pair with food/exercise notes for actionable n=1 data.
Don’t over-interpret single spikes.
Aim for stable mean and low variability rather than chasing flat curves.