Over 600 people on five continents have received talactoferrin. Oral doses of up to 15 grams/day have been administered, and some patients have taken talactoferrin for over two years and consumed over 3,000 grams in the course of their treatment. Despite the high-doses and long-term administration of talactoferrin, the drug has been well tolerated with no dose limiting toxicities.

Talactoferrin safety has been tested in mice and monkeys. In Good Laboratory Practice (GLP) toxicity studies in mice, oral talactoferrin was given as a single dose up to 5,000 mg/kg, and as a 30-day repeat dose up to 1,000 mg/kg/day. A 6-month toxicity study was also performed in Cynomolgus monkeys at doses up to 1,000 mg/kg/day. No drug-related toxicities were observed in any of these studies.

Talactoferrin was shown to be non-mutagenic in bacterial mutagenicity assays (Ames), non-clastogenic in an in vitro cytogenetic assay, and non-allergenic in mice.