Does cutting water before a show make your muscles look sharper?

Short answer

No. Cutting water also drains water from muscle; on hydrated days muscles were 13% thicker. What filled the muscles and thinned the layer under the skin was carbs and low body fat, not cutting water.

Does cutting water before a show make your muscles look sharper?
'Cut water → less water under the skin → sharper muscles' — does this formula hold?
A common belief: drink lots of water in the days before a show, then cut it the day before, and the water under your skin drains so your muscles pop. We checked step by step whether cutting water really drains only the water under the skin.
Most people manipulate water
It is the second most common trick after carbs
In a survey of 81 people, 76 (93.8%) changed something in the final week, and water manipulation was the most common method after carb manipulation. In a survey of 160, 40.6% used water loading.
But cutting water drains muscle water too
For every 1% of body weight lost, muscle water fell 1.2%
When 8 people sweated off 2-6% of their body weight, every 1% drop in body weight cut the water in their blood by 2.4% and the water in their muscles by 1.2%. Water did not leave only from under the skin.
Muscles got thinner
On the day they drank, muscles were 13% thicker
14 people did the same workout once after 24 hours without water and once while drinking normally. On the hydrated day, their muscles were 13% thicker. Cutting water shrank the very muscle they wanted to show on stage.
Flip side: sharper without cutting water
1 case: the layer under the skin got 10% thinner
1 person did not cut water before his show. He drank about 49% more and raised carbs, and was never dehydrated. From 3 days out to show day, his muscles got thicker, the layer under his skin got 10% thinner across 7 sites, and 43% thinner on the back of the arm.
What filled the muscles was not cutting water
Only those who ate carbs looked bigger
Among 24 people measured right before a show, only the 15 who ate lots of carbs gained arm muscle thickness, girth and photo scores. The 9 who did not showed no change. Sugar stored in muscle pulls water in with it.
Cutting water plus drugs turns dangerous
1 man's potassium fell to half of normal
1 man took a diuretic (water pill) and cut water. His potassium fell to 1.8 (normal 3.4-4.5) and his arms and legs were paralyzed. In a study following 10 people, muscle markers still dropped during show week despite diuretics.
Bottom line: cutting water shrank muscle first
Carbs and low body fat create the sharp look
Cutting water drained not just the water under the skin but the water inside muscle, and muscles got thinner. Carbs filled the muscles, and the 1 person who never cut water still got a thinner layer under the skin. Focusing on carbs and body fat, not on cutting water, is what the research supports.