Adverse effects, although rare and of short duration[3] are limited to anxiety, insomnia, drowsiness and agitation. It may be safe for up to 18 months in humans at doses of 3.2g daily[49] with one year-long study in ambulatory patients with Alzheimer's using 8g daily reporting no side effects.[45] Piracetam also appears to have clinical usage (and a lack of side effects) when used in youth for the purpose of Breath Holding Spells at oral doses of 50-100mg/kg bodyweight in children aged 5-60 months.[68][67][66]

In animal models (rodents, dogs, and marmoset), an LD50 failed to be established at the dosage of 8-10g/kg bodyweight in those three species.[25][108]

Piracetam appears to be quite non-toxic at common doses used, and a few studies exceeding recommended dose (4.8g daily) fail to find toxicity associated with Piracetam
In general, racetams (usually referring to Class I racetams; Pi-, Ani-, and Oxi-) are said to have little side effects and low toxicity rates at commonly used dosages and up to 12g for up to 8 weeks.[25][109][110] However, a possibility for adverse drug-drug interactions persists for Piracetam due to it interacting with blood in an anti-clotting manner (and such, caution should be taken when pairing Piracetam with pharmaceutical blood thinning agents such as Warfarin or potent nutraceutical options).