In early 2023, Viking started a Phase 1 clinical study on the oral formulation of VK2735. The 28-day study showed that taking oral VK2735 led to noticeable weight loss. Participants who took VK2735 lost up to 5.3% of their body weight. Compared to those who took a placebo (a pill with no medicine), VK2735 users lost up to 3.3% more weight. Even after stopping the medicine, the weight loss effect continued for six more days, with participants losing up to 3.6% more than those on placebo. About 57% of people taking VK2735 lost at least 5% of their body weight in 28 days, while no one in the placebo group did. Viking believes that taking VK2735 for more than 28 days could lead to even more weight loss.

VK2735 also showed good safety and tolerability over the 28 days of daily dosing. Most side effects were mild, with 76% being mild and 24% moderate. For stomach-related side effects, 79% were mild. Some people (14%) had mild nausea, but no one vomited. One person had diarrhea, compared to two people in the placebo group. Overall, there were no significant differences in stomach problems between those taking VK2735 and the placebo. No serious side effects have been reported.