Procedures (methods): Participants will be sequentially assigned to enroll in a dosing arm, beginning with maraviroc, then dolutegravir, and ending with tenofovir/emtricitabine. All participants will take a single observed dose of study product in Phase 1, with blood and hair samples obtained on Days 3, 7, 14, 21 and 28 days post-dose. In Phase 2, all participants take 28 days straight of daily dosing, observed, of the same study product. Blood and hair samples obtained on the same days post-dose. In Phase 3, participants will be randomized to stop their drug, or decrease dosing to one or three doses weekly. Hair and blood samples will again be obtained on the same days post-dose. All participants will complete a follow-up safety visit with 14 days of completing study sampling.