66, fit, slender. Would Co2 help with sun damage and muscle loss on upper arms?

I am very fit, always slender. Extensive sun damage from tanning 3 decades ago. This year, i have lost alor of muscle although I am avid outdoors hiker, biker, climber etc. My arms and legs have become scrawny and especiall my arms from inner srmpit arear to shortly south of elbow are very crepey, arms of 80+ woman. Can CO2 treatments help? There is no fat on my arms