Total weekly volume matters more than how many times a week you train
It's easy to assume that training 5 times a week is by definition more effective than 3 — more sessions should mean more progress. But studies that equalize total weekly training volume (total sets per muscle group) between groups training at different frequencies usually find similar gains in strength and muscle mass regardless of whether that volume is spread across 3 or 5 sessions — as long as the total number of sets per muscle group matches.
That doesn't mean training frequency doesn't matter at all — it has its own benefits unrelated directly to muscle growth: more frequent, shorter sessions are easier to fit into a busy schedule, they reduce fatigue accumulation within a single session, and they help maintain higher-quality technique on each individual set instead of fading focus toward the end of a long workout.
Practical takeaway: if choosing between hitting the gym 3 times a week with a bigger volume per session versus 5 times with less volume per session at the same total weekly sets per muscle group, the choice of frequency should come down to schedule convenience and personal preference — not the assumption that more sessions automatically means more progress.