Truvada for PrEP is generally safe and well tolerated. Most people on PrEP report experiencing no side effects, but some side effects were reported in clinical trials. Participants in the iPrEx study reported side effects that fall into four main categories (ordered here as most to least common):

  • Nausea:¬†9% of those who received Truvada reported nausea in the first month, compared with 5% of those who received placebo. After the first month, there was no difference in reported rates of nausea among those who received Truvada and those who received placebo.
  • Headaches: 4.5% of participants who received Truvada reported headaches, compared with 3.3% of those who received placebo.
  • Weight loss: 2.2% of those who received Truvada reported unintentional weight loss of more than 5%, compared with 1.1% of placebo users
  • Small increases in serum creatinine:¬†Truvada is known to cause small increases in serum creatinine, a naturally occurring molecule filtered by the kidneys. In this study, 0.3% of those who received Truvada experienced mild increases in serum creatinine that persisted until the next test. Creatinine levels went back down once these participants stopped taking PrEP. Four of the five participants restarted PrEP without recurrence of the creatinine increase. Investigators monitored kidney function throughout the study and found no serious problems.

For most people, these side effects went away on their own after the first few weeks of taking Truvada, or when the medication was stopped.