Yes, this is absolutely a normal amount. I'm an amateur/hobbyist marathon runner, and I usually take about 300mg pre-race in the form of coffee, and top up anot

Yes, this is absolutely a normal amount. I'm an amateur/hobbyist marathon runner, and I usually take about 300mg pre-race in the form of coffee, and top up another 100mg in the form of a gel about once per hour. This is roughly in line with the amounts that are recommended by most race-day nutrition plans.