Increases in pubertal hormones such as estrogen, thyroid hormones, growth hormone, insulin, and insulin-like growth factor-1 promote vasodilatation and decrease blood volume. Very interesting article about the imbalance of hormones in women especially high estrogen that causes orthostatic hypo.. User RepulsiveAd4500, in the Postural Orthostatic Tachycardia Syndrome (P.O.T.S.) subreddit, 30 Aug 2021