Do cold showers really make your skin tighter?
Cold showers do not make your skin tighter; frequent showering can actually damage the skin barrier and cause dry skin, regardless of the water temperature.
Cold showers do not make your skin tighter. The two available studies say something quite different: frequent showering can actually damage the fatty layer and moisturising substances in the outermost layer of the skin. That is more likely to lead to dry, flaky skin than to a firmer or tighter appearance.
Cold weather is also cited in the same research as a factor contributing to dry skin. The combination of cold air and regular showering can deplete the skin barrier further. No direct mechanism by which cold showers would tighten the skin is described anywhere in the available studies.
The only source in this review that mentions 'skin becoming tighter' concerns a serious disease in which the body produces excessive connective tissue. That is an entirely different situation and in no way comparable to what people mean when they say that a cold shower tightens the skin.
In short: the idea that cold showers structurally tighten your skin is not supported by this research. If you want to protect your skin, it is wiser not to shower too frequently or for too long, regardless of the water temperature.
Two observational sources on dry skin as a result of showering and cold weather; one case report on skin tightening as a disease manifestation. No RCTs, no mechanistic skin research specifically into cold showers.