Sweat is a breeding ground for odor-causing bacteria. You can usually hand-wash synthetic gloves gently in lukewarm water with a bit of mild soap. However, leather gloves must never be soaked or thrown in the washing machine! If you do, the leather will dry rock-hard and crack. Just wipe leather down with a damp cloth, and always let your gloves air out thoroughly in a well-ventilated space after every workout (never on a hot radiator).
Leather gloves are the ultimate symbol of durability. They will survive years of heavy abuse and offer superb protection, though they are less breathable. Synthetic (neoprene or fabric) gloves, on the other hand, are extremely lightweight, vent sweat fantastically, and often feature an anti-slip silicone print on the palm. If you lift seriously heavy weights, choose leather; if you prefer dynamic cross-training and maximum breathability, go with synthetic.
These models are absolutely brilliant for heavy pressing exercises (bench press, overhead shoulder press). You wrap the long band of stiff fabric tightly around your wrist, locking it into a straight, neutral position. This protects your joints from dangerously bending backward under a heavy barbell. However, if you mostly train with lighter weights or do pull-ups, a classic, shorter glove will be completely sufficient.
It's very simple. Take a tailor's measuring tape and measure the circumference of your palm at its widest point (just above the thumb, across the knuckles), keeping your hand slightly bent as if gripping a bar. Simply compare the resulting centimeters/inches with the product's sizing chart. Keep in mind that leather gloves will stretch slightly and mold to your hand after a few workouts.
Gloves are an absolute guarantee if you want to keep your palms soft and free from painful calluses and torn blisters. They also perfectly prevent the barbell from slipping out of sweaty hands. However, it is true that during extremely heavy deadlifts, a thick layer of leather on your palm can slightly hinder your grip strength (lifting straps are better for that). But for 95% of standard machine and dumbbell workouts, gloves are an invaluable tool for your comfort.
