Hi i am 18 and 5'10" and i am taking calcium for height increase.is it helpful?please i need some advice . my friends in same age are 6'1"and higher.

Calcium doesn't help: to increase your height, 5'10" is very reasonable, ultimate height depends on many factors, the most common of which is constitutional: your natural built, if you are really that concerned visit an endocrinologist (glands doctor), goodluck

You are likely done: If you entered puberty the same time as your friends and your bone maturity is that of a 18 yo there is little you can do to increase your height.A single x-ray of your left hand can be assessed for bone maturity.If 18, you are done growing, if bony maturity is more like 15 you might grow an additional couple of inches.If your growth centers r closed you are done.

Won't help: 5'10 is a fine height for a guy. A little taller than average. At age 18, you're almost certainly reached your maximum. Shorter men are more agile, and it's a plus for several sports, famously gymnastics and climbing. A man seeking a friend is likely to choose a shorter guy, and you can be wiser and funnier without being disliked. Your fitness / musculature overrides height & you control it.