Raspberry Pi Max current with GPIO for LED

Note: withdrawing more current(~15mA) from GPIO can affect the Rpi
https://raspberrypi.stackexchange.com/questions/9298/what-is-the-maximum-current-the-gpio-pins-can-output

• Use 5V Pin (2,4)
• Use GPIO as Negative volt
• Max current withdrawn was 23mA for my use case

import RPi.GPIO as GPIO
from time import sleep 
import sys

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(21, GPIO.OUT, initial=GPIO.HIGH)

if sys.argv[1] == "on":
    GPIO.output(21, GPIO.LOW)
    #print("on")
    exit()

Fore More brightness:

• Add multiple GPIO as GROUND
• After adding GPIO20 as ground it was taking ~18mA from GPIO20
• And Overall of ~36mA from both GPIO 20 and 21