Welcome to my Dragon Ball Super theory on Super Saiyan Red (god) vs Super Saiyan Blue. There is no official statement from anyone on what form is more powerful.
The only statement we have was from Akira Toriyama about a year before the blue form was even known about in which he states this:
“Simply put, it’s because [the red hair] looks so strong,” said Toriyama. “The color yellow has already been used, and blue isn’t really that strong looking, so visually, red is easy to understand.”
Most fans would make assumption that Super Saiyan Blue is stronger than Super Saiyan Red, because Blue form is the last form to be used by Goku and Vegeta after Super Saiyan Red.
Saiyan prince, Vegeta was able to achieve Super Saiyan Red as well and access it at will, just like Goku. They both also succeeded in achieving Super Saiyan Blue, which is next transformation of Super Saiyan Red.
Even though Blue form is after Red form, there is a good reason for this debate if Super Saiyan Red is stronger than Super Saiyan Blue or not.
The Red form has more stamina, more speed but less power compared to Blue form, not by a lot but a little. In Dragon Ball Z: Battle of Gods, Beerus said he was using 70% of his power against the Red Super Saiyan God form. However, in Revival of F movie Whis tells Goku and Vegeta that they could only beat Beerus if they fought together, and that was when they achieved Super Saiyan Blue form.
The thing here is Red form held it’s own against Beerus in Battle of Gods, and was able to push Beerus to 70% of his power. Blue form is supposed to be stronger than Beerus, but it’s not. Allow me to explain.
The Blue form is indeed stronger than Red form(don’t get mad, sit tight and read), because when Vegeta uses Super Saiyan God Red form against Goku Black, this is what Goku Black says “You must be out of your mind, using a lower form to beat me?”. The main point here is, Vegeta figured out how Super Saiyan Blue and Super Saiyan Red works.
Which Goku later explains it as well. While fighting Goku Black, Vegeta was switching between Super Saiyan Red and Blue in an instant. While moving Vegeta was using Super Saiyan Red but while attacking, he was using Super Saiyan Blue. There’s a reason behind this, Super Saiyan Blue uses so much Stamina and is slower than Red form, while on the other hand Super Saiyan Red gives more stamina and is faster than Blue form, but less power compared Blue.
Vegeta was using Super Super Saiyan Red to supplement Super Saiyan Blue, as I mentioned above, by switching forms in an instant, Vegeta was able to keep up his stamina much easier than Goku Black, and you know what happened in their fight.
Conclusion: Super Saiyan Blue is stronger than Super Saiyan Red, however Blue form eats up a lot Stamina and is slower than Red form, on the other hand Super Saiyan Red is faster than Blue and uses less Stamina. Super Saiyan Blue has a time-limit, Super Saiyan Red doesn’t.
This was my theory on Dragon Ball Super, I hope you like it, leave comments below and let me know what you think.