Extended release describes a formulation designed to release its active compound over an extended period of time rather than as an immediate bolus on dissolution. The intent is usually a flatter exposure curve, fewer doses per day, or both. Format choices interact with dose interpretation and with the route of administration, so an extended-release tablet or capsule is a meaningfully different dose form from an immediate-release one even at the same milligram total.
How extended release works
Common approaches include matrix tablets that release as the surrounding material erodes or hydrates, multi-layer tablets that stage two or more releases, and capsules filled with coated beads that dissolve at different rates. Some products use pH-sensitive coatings so that release begins further down the GI tract. Each method produces a different release curve, and two products both labeled "extended release" are not necessarily equivalent.
Why splitting or crushing changes the dose
Cutting, crushing, or chewing an extended-release product can destroy the release mechanism and convert the daily dose into an immediate-release spike. For some ingredients that spike is uncomfortable; for others, it raises a safety concern. As a default, extended-release products should be swallowed whole unless a clinician has approved a different practice for a specific product.
What this means for the log
The same milligram value can behave differently in an extended-release product than in an immediate-release product. The intended pattern is a slower onset and a longer release curve, not a simple one-to-one match with the immediate-release form. A user who switches between formats at the same milligram total has changed exposure even though the number on the bottle did not move. Recording the format alongside the dose preserves that distinction and supports the single-variable change discussed in understanding dose windows and cycles.
Where it commonly appears in supplements
Magnesium products sometimes use extended-release formats. Some caffeine products are sold as timed-release or sustained-release for users who want a flatter morning curve. Niacin products also appear in extended-release formats because of the well-known flushing pattern of immediate-release nicotinic acid. The labels for these vary in how clearly the release pattern is described.
Uncertainty and limits
Evidence is limited on the magnitude of plasma differences between extended- and immediate-release versions of the same supplement across populations. Evidence is limited on whether label terms like "sustained release," "timed release," and "extended release" describe identical mechanisms across brands.
How this appears in Unfair
Unfair stores release format on library entries and treats it as a distinct field from milligram dose, so a switch between an extended- and immediate-release version of the same ingredient is recorded as a format change.
Clinical safety note
Do not split, crush, or chew an extended-release product without confirming with a clinician or pharmacist; if a swallowed product produces an unusually strong or short response, the release mechanism may have been compromised and the product should be paused.