The Martingale isn't a trading system: it's a staking (in this context "position-sizing") system.
It's based on a fundamental statistical/mathematical misunderstanding related directed or indirectly to something called the "gambler's fallacy".
It makes no sense at all to use it in trading.
Either a method has a genuine edge or it doesn't: if it doesn't, then it can't safely be given one by increasing the stakes after a loser, and if it does, one doesn't need to anyway.
There's no sense or logic at all in allowing previous results to influence the position-sizing of future trades (other than gently increasing the position-size as the account grows, and/or vice-versa, obviously).
Edited to add: this is quite a good website with sensible things to say about Martingales (its conclusion is "don't waste your money", and its conclusion is correct).
I have used a limited martingale on a roulette wheel, playing red, just for entertainment, if you get a choppy wheel that is going back and forth between red and black you can make some fast money, but if you stay to long a short losing streak can wipe you out.
Closes thing I have seen to a martingale in trading is "Dollar cost averaging" works for long term holds in something like an Spider ETF but not something I would want to try with Forex