What type of Calcium supplement should I take? I'm 81, on Prolia.

I prefer calcium citrate to calcium carbonate. Harvard Health says it's easier for our bodies to absorb, an important point as we get older. I find the petites to be easier to swallow. I take three of the petites at a time, to get to the 600 mg. But you should discuss how much that you need to take with your doctor.

According to National Institute of Health, it's better to use smaller calcium supplements. Taking a single 1000 mg pill is not productive. You're better off taking two smaller pills at different times of the day.

"The percentage of calcium absorbed from supplements, as with that from foods, depends not only on the source of calcium but also on the total amount of elemental calcium consumed at one time; as the amount increases, the percentage absorbed decreases. Absorption from supplements is highest with doses of 500 mg or less. For example, the body absorbs about 36% of a 300 mg calcium dose and 28% of a 1,000 mg dose."

I wouldn't disagree with that. But as we get older, we cannot absorb as much, for various reasons. Considering my age, my doctor [endo] has asked that I take more. That is why I suggested that an 80+ year old should talk to their doctor.

Here is an article from our sponsor that covers it well.
https://newsnetwork.mayoclinic.org/discussion/calcium-intake-for-adults-over-age-55/
My wife and I I take BoneUp by Jarrow 1000mg and contains Vit.C, Vit D2, Elemental Calcium, magnesium, zinc, cooper,manganese and potassium plus Bit K2 necessary to absorb the calcium. They sell a does requiring 1 tablet 3x a day and a dose requiring 2 tablets 3x a day. If you have swallowing difficulties buy the 2 tablets size. I’m also on Alendronate 75mg