Brooks Glycerin 23 vs Brooks Glycerin GTS 23:
Which to Choose

Underfoot these two are close cousins: the same DNA Tuned dual-cell midsole (soft, larger heel cells for cushioned landings, smaller firmer forefoot cells for a hint of push), the same plateless, comfort-tuned character, and near-identical proportions — the neutral Glycerin sits on roughly a 37 mm heel / 29 mm forefoot stack at about 303 g, the GTS on 38 mm / 28 mm at about 306 g. That 3 g difference is negligible, so this isn't a case of one being meaningfully lighter or more cushioned; the plushness and the "happy at conversational pace, vague if you force it" ride carry over to both. The two genuine differences are guidance and geometry. The GTS 23 adds GuideRails support and a wider, more sidewalled base, pushing its stability from the standard Glycerin's already-planted-but-neutral feel up to a firmly supportive one that gently reins in a collapsing stride without feeling corrective or clunky. It also rides on a slightly steeper 10 mm measured drop versus the Glycerin's 8 mm, a touch more heel-forward geometry that eases the calves and Achilles. The GTS reads as marginally more responsive at toe-off thanks to that support structure, but neither is a snappy shoe. One practical consequence: the neutral Glycerin's best-distance range stretches to the marathon at relaxed effort, while the GTS is happiest capping out around the half — both are strongest as steady daily and long-run trainers, not tempo tools.