I made the rookie mistake of starting Tongkat Ali at 600mg because someone on a bodybuilding forum said that "400mg is for beginners" and that "real results start at 600mg." This was dumb.
Day 1: Took 600mg with breakfast. Within 2 hours I felt uncomfortably warm — not like a fever, but like my internal thermostat had been cranked up. Sweating more than usual at my desk job.
Day 2: Same warmth, plus nausea that lasted about 3 hours after dosing. Took it with food but it did not help much. That night I could not fall asleep until 1am despite going to bed at my usual 10:30pm. Just lying there with my mind racing and my body feeling wired.
Day 3-5: Nausea persisted. I was irritable. My resting heart rate was up about 8 bpm according to my Apple Watch. Sleep continued to be disrupted — not total insomnia, but taking 45+ minutes to fall asleep when I normally fall asleep in 10.
Day 6: Dropped to 200mg. Everything resolved within 48 hours. Nausea gone, sleep normalized, heart rate back to baseline.
I stayed at 200mg for a month, then moved to 400mg. At 400mg I had zero side effects and started noticing the subtle energy and mood improvements people describe. The lesson: Tongkat Ali has a real dose-response curve for side effects, and jumping to a high dose is counterproductive. Start low. There is absolutely no reason to take 600mg unless you have tried 400mg for months and want to experiment cautiously.
Also worth noting: the nausea at 600mg was bad enough that I would have quit entirely if I had not read other reports about dose-dependent side effects and known to reduce the dose rather than just stop.