Biceps 20. Triceps 20.

It really depends on your lift. 8 lbs is good, but then try 8 lbs on a bench at 45 degrees and your arms out to the side while doing curls. It will be much harder and better because you’re really isolating your biceps. Also try hammer curls to work different aspects of your arms. You will probably be able to do less.

I've been doing Peloton arms classes, mostly 20 min ones, for about 6 months now and notice a big definition in my arms. Not so much that anyone will confuse me for a bodybuilder btu I notice!
I started with 8 and 10 pound weights for biceps, now can do 15. Still can't lift more than 10 for shoulders or anything overhead.

OP you should join like, I mean I know not everyone is about Peloton, but join Peloton free for 60 days. Just the app on your phone not the bike or anything. You can take tons of arms and light weight and upper body/arms and shoulder classes. They will take you through sets and tell you when to push for heavier weights and talk about form.

If you join for free 60 days and do arms 2-3 times a week then by the end you'll probably have enough info to continue on your own if you don't want to pay the monthly fee, or you will have seen the value and keep going with their classes.

OP here, thank you! So how many times a week should I be doing weight training for upper body? which exercises and how many reps?
thank you so much!

Your goal should be just to increase at the pace that's right for you, not a specific target amount.

One way to increase is to do fewer reps of a higher weight until you can't do anymore and then finish out the set with a lower weight. So see if you can do 2 reps of an exercise with 10 lbs--or even 1 rep--and then do the rest with 8. If you're too exhausted to finish out with 8, switch to 5. You want to get to the point where you really struggle to lift it one more time in good form. If you can easily do a set of 10 with a weight, you'll maintain but not increase strength.

I started at 8 too. Now I'm at 12. Depending on the set, I still drop down to my 8s if I need to. Progress slowly. When you can finish the rep count without fatigue, you've outgrown the weights and time to move up to 10s and then 12s.

Probably no more than 15lbs. Keep lifting 8 and gradually work your way to 10. Maybe focus more on overall reps than trying to increase weight. 8lbs isn't that bad at all.

At this time i can only lift 8 pounds for bicep, tricep curls , what should my goal be to build up to? how many pounds, late 40s female with nl BMI but very low muscle mass and chronic medical issues/ arthritis