Generally speaking, the recommendation for dosage on most supplement labels are for a 150 pound adult. Knowing this can help you adjust the dosage depending upon your personal needs.

That being said, nobody really knows exactly how many vitamins, minerals, and other nutrients we need on a moment-to-moment basis. Many nutritional practitioners feel that the government guidelines are too low in the first place, and will compensate for that in their recommendations. Our needs are constantly changing and the best we can do is have general guidelines. For instance, if you feel a little run-down, you might want to increase vitamin C and other antioxidants. Or if your muscles cramp in the middle of the night, you might think to drink some magnesium powder in your water.

So what might be a good rule-of-thumb for you? Here’s what I do:
Eat the best you can – the highest nutrient-dense, organic, locally sourced food as possible.Take some high-quality foundational nutritional supplements like whole-food based multiple vitamin/minerals, fish oil, digestive enzyme, probiotic, etc. Adjust the dosage for your body weight.
Increase your intake if you are under excess stress at certain times.
Contact a health care practitioner who knows nutrition if you have questions.