Coffee/ tea/ energy drinks are all the same thing, Caffeine.
From my toxicology notes a caffeine hit, will take effect after 5 minutes, and will peak after 30 minutes. It will have a half life of 4 hours (about 1 % is passed in urine), which means half of it will be gone in 4 hours, meaning in 12 hours 6% will remain. It is metabolized in the liver, and smokers will feel a slightly stronger hit than non-smokers.
The important thing for your health is that it can build up in your system. Going off caffeine can have withdrawal side effects even at low levels of intake [Anxiety, irritability, drowsiness, headache]. Sleep will be shortened, and lighter when on caffeine. Caffeinism (overdose, 500-600 mg) occurs with a daily dose of around 10 cups of tea/ instant coffee (as little as 3 cups of strong coffee) [Anxiety, headaches, dizziness, diarrhoea, irritability, hands shaking, and cardiovascular problems].
As you can see by the side affects of heavy intake or withdrawal will have implications for how you behave/ who you are on cam. If you cam close to sleep time, keep your intake lower to avoid interrupted sleep (something like chocolate will give a lower dose). Other than that use your intake carefully, and in a well timed fashion, always being mindful of how long it takes your system to remove it.
Alternatives to caffeine include the correct use of light (use of darkness for that matter) and controlling your melatonin levels. Proper sleep and a healthy lifestyle are critical to not feeling reliant on caffeine to stay alert.
Models work in a bright environment, this also can affect your health. One suggestion for a small boost in alertness is to take breaks in darkness, bright light will then create a mini biological morning. Explore how different light/ darkness situations affect your mood to find the right one for you.
Finally try apples. Apparently apples can keep you awake.