Whoop got into hot water with the US Food and Drug Administration (FDA) in July over its latest blood-related feature, Blood Pressure Insights (BPI). The FDA sent it a warning letter to stop advertising its watches as blood pressure monitors without approval. "The FDA has not authorized BPI for any use, including for the measurement or estimation of a user's blood pressure," the letter reads. Whoop is still in talks with the FDA over the blood pressure feature. The Trump administration seems to acknowledge wearables as legitimate health devices.