How to Read a Supplement Label: A Checklist for Men Over 50

The front of a supplement bottle is advertising. The back is where the information lives. In the United States, the Food and Drug Administration sets rules for what a supplement label must show, and once you know where to look, you can size up almost any product in about two minutes.

Here is what to read, in the order we read it.

1. The Supplement Facts panel

Every dietary supplement sold in the U.S. must carry a "Supplement Facts" panel. It lists the serving size, the number of servings in the container, and each ingredient with the amount per serving. For vitamins and minerals, it also shows a percentage of the Daily Value.

Two things to check here:

• Serving size. Amounts are listed per serving, not per capsule. If a serving is three capsules, the numbers you see take three capsules to reach.
• Servings per container. Divide the price by the number of servings and you have the real daily cost, which is the only fair way to compare products.

2. Proprietary blends

Some labels group several ingredients under a single name, a "proprietary blend", and give one total weight for the group. That's legal. It also means you can't see how much of each ingredient you're getting. A blend isn't a reason to walk away by itself, but a product that is open about its amounts makes your homework easier and tells you something about the company.

3. The other ingredients

Below the panel you'll find "other ingredients": capsule material, fillers, colors and flow agents. This is where to check for anything you avoid, such as gelatin, gluten, soy or dairy, and for allergen statements.

4. The claims, and the line that comes with them

Supplement makers may describe how an ingredient supports the normal structure or function of the body. They may not present a supplement as a medicine for any disease. When a label makes a structure-or-function statement, it must carry this sentence:

"These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."

Seeing that line is normal. What should make you cautious is the opposite: language on a label, a website or an ad that sounds like a medical promise.

5. Who makes it, and how to reach them

The label must name the manufacturer, packer or distributor, with an address. Look for a working phone number or website as well. A company that is easy to contact is a company you can hold to its guarantee.

6. Quality seals

The FDA doesn't approve supplements before they go on sale. Some makers pay independent organizations to test their products for identity, strength and contaminants and print a seal when they pass. A seal is a plus, not a requirement, and you can check most seals on the certifier's own website.

Questions to ask your doctor or pharmacist

If you take prescription medication, bring the bottle, or a photo of the label, to your next appointment or to the pharmacy counter. Ask:

1. Does anything here interact with what I already take?
2. Is there a reason to avoid any of these ingredients with my history?
3. Is the amount per serving sensible for someone my age?

Pharmacists answer these questions every day, and it costs nothing to ask.