Ala-Kul gets most of the attention, and for good reason — but it's also the busiest trail out of Karakol in peak season. The Karakol–Jyrgalan route is the quieter alternative for trekkers who want a similar caliber of scenery with far fewer people on the trail.
A 1-3 day trek to a striking turquoise lake at 3,560m, with well-worn trails, established camps, and — especially in July and August — a steady stream of other trekkers on the same route.
A 4-6 day traverse connecting Karakol to the Jyrgalan valley over a series of high passes. Fewer other trekkers, more genuinely remote camping, and a real sense of covering ground rather than an out-and-back.
If you have 1-3 days and want an easier logistics footprint, Ala-Kul remains the classic choice. If you have closer to a week, have done Ala-Kul before, or specifically want solitude, the Jyrgalan route is worth the extra planning.