Beginner’s Guide to Shopping for Dietary Supplements

(Wikimedia commons)

Learn what supplements can do, and which ones are right for you


December 10, 2018 Updated: December 10, 2018

It’s no secret that dietary supplements are popular. In fact, according to a report conducted by Grand View Research, the global supplements market was valued at $133.1 billion in 2016 and is projected to rise annually by 9.6 percent between now and 2024. But not all dietary supplements are created equal. While some supplements possess positive health benefits and provide desired results, others can prove to be the opposite of what your body—or wallet—needs. And while choosing the wrong supplement can result in wasting money on a product that simply doesn’t work, a more serious complication can be an adverse reaction to one or more of the listed ingredients. In short, it’s vital to understand what it is that you’re purchasing and why. If you’re interested in learning more about how to incorporate dietary supplements into your diet, here is a beginner’s guide on what to keep in mind when shopping—from figuring out what works best for you, to safety and efficacy.

Differences Between Dietary Supplements and Prescription Drugs

Dietary supplements, according to the FDA, are “products taken by mouth that contain a ‘dietary ingredient,’” and can include “vitamins, minerals, amino acids, and herbs or botanicals.”

They’re designed to increase dietary intake rather than treat, diagnose, prevent, or cure diseases. Even though they’re not meant to be used this way, people still use them this way in hopes of improving their health and to self-treat many conditions, ranging from arthritis and headaches to heart disease.

It’s important to remember, however, that dietary supplements are regulated much differently than drugs.

“Supplements usually do not require ‘pre-market’ approval before they are sold in stores,” explains pharmacist Philip Gregory.

“As a result, individual ingredients or specific combinations of ingredients do not need to be proven safe and effective before they are sold.”

It’s important to keep in mind that supplements don’t have an approval process like prescription drugs do. For this reason, it can be hard to know how beneficial a supplement might be, how safe it is, or what side effects it might cause.

Dietary supplements

Claims made by supplement brands may not always be supported by reliable evidence. Some supplements can interact with prescriptions or over-the-counter medications, while others might not be safe if you have certain conditions.

For these reasons, its vital that you do your research before adding a new supplement to your routine.

What to Consider Before Choosing to Take a Supplement

Before you decide to stock up on a specific supplement, Gregory suggests that the first question you should ask yourself is: Why am I taking this?

“Is it for general health or a specific health or medical issue? If the reason for taking it is clear, it’s easier to determine if the supplement is a good choice.”

Once you’ve clearly identified your reason for choosing a specific supplement, your next step is to check the ingredients.

Here are a few things to consider:

• What are each of the ingredients?
• Are the ingredients generally safe?
• Will the ingredients interact with any prescriptions or over-the-counter medications and supplements you’re already taking?
• Are the ingredients likely to cause unwanted side effects?
• Will any of the ingredients trigger allergic reactions, including those used for the pill’s coating or coloring?
• Are the ingredients listed actually beneficial for a specific purpose?
• Is the product itself known to be high quality?

How Can You Tell If a Supplement Is Safe?

Just because a dietary supplement is sold in a pharmacy or health food store, or claims to be “all-natural,” doesn’t mean it’s safe or free of side effects.

Moreover, while supplements are sold without a prescription, they can still have both negative and positive drug-like effects, as well as side effects from interacting with medications and other herbs. Consequently, they should be taken with similar precautions.

“The big question is whether the supplement does more good than bad—is it more helpful than harmful when taken in a therapeutic dose?” said Dr. Gregory.

There are a few things to remember when determining whether a supplement is safe. These include:

• Check whether it’s been scientifically tested on people, rather than on animals or not at all. Also note whether the tests provided favorable results.
• Remember that testimonials on a manufacturer’s website may be inaccurate or not supported by scientific research. For this reason, it’s best to consult an unaffiliated source.
• Consult the National Institute of Health’s Office of Dietary Supplements for reliable information and research that includes fact sheets for individual supplements, advice for consumers, recommendations, and studies. Other websites, including MedlinePlus and Memorial Sloan Kettering’s About Herbs section are also quality resources.
• Be wary of supplement brands that make promises about the results that seem unrealistic or too good to be true.

Stay in the Know

Supplements designed for bodybuilding, weight loss, or sexual enhancement are most likely contaminated with other substances like drugs, especially when bought online. Only buy supplements from reputable sources.

While a supplement needs to be safe for the general public, it also needs to be safe for you.

Supplements can cause negative side effects when combined with other supplements or medications, and when taken after specific medical procedures, during pregnancy, or while breastfeeding.

For those on medication, talk to your doctor or pharmacist before taking a new supplement to ensure that they’re not known to cause unwanted side effects when taken alongside your current drug regimen.

Some of the more common supplements and their interactions include:

St. John’s wort. This has the potential to decrease the effectiveness of birth control pills, cancer chemotherapy, and other medications.
Valerian. Taking this herb with medications that cause drowsiness can increase your risk of excessive tiredness or fatigue.
Goldenseal. Taking this supplement can increase your risk of side effects from drugs that are substrates of cytochrome P450.
Calcium. This supplement may reduce absorption of certain antibiotics, zinc, iron, or magnesium as well as drugs for an underactive thyroid.
Ginkgo. This herbal supplement increases the risk of spontaneous bleeding for those on warfarin or other blood thinners.
Ginger. This increases your risk of bleeding when taken with warfarin or other blood thinners, as well as nonsteroidal anti-inflammatory drugs (NSAIDs).
Garcinia. Taking this supplement with antidepressants and some other medications can raise serotonin in your body to dangerous levels, potentially leading to serotonin syndrome.

How Can You Tell If a Supplement Is Effective?

Much like determining a supplement’s safety, its efficacy can also be verified through doing your research using reputable sources.

Again, check whether clinical studies of the supplement as a whole—and the ingredients on their own—were performed on humans rather than only on animals or in test tubes.

Specifically, look to see if the supplement has been scientifically tested to correspond with your intended use. For example, if you’re taking a probiotic to reduce the risk of a cold, double check that there’s substantial evidence to support this purpose.

Dietary supplements

Also, watch out for claims based on traditional uses that may not be backed up with scientific evidence.

“Traditional uses often have some basis in fact, but not always,” adds Gregory.

How to Determine the Quality of a Product

To determine the quality of a product, you can look to third-party testing programs such as the United States Pharmacopeia and National Science Foundation (NSF). These programs determine whether the supplement contains the ingredients that the label states and nothing more, nothing less.

For a supplement to receive the United States Pharmacopeia Verified Mark, it must:

• contain the ingredients listed on the label in their stated potency
• not contain harmful levels of contaminants, such as lead and mercury
• break down and release into the body for absorption
• be made in accordance to the FDA’s Current Good Manufacturing Practices (CGMP)

Meanwhile, the NSF has multiple testing services to determine quality and CGMP compliance. NSF Certification refers to the adherence of quality control standards, and compliance to regulatory and purchase specifications.

To be certified, a product must go through yearly testing and the manufacturing facility must undergo annual inspection.

Dosing for Supplements

Supplements are labeled with dosage recommendations, however it’s best to do your own research to determine the right amount for you.

When taking vitamins and minerals, it’s important to know whether your diet already includes the same ingredients as the supplements themselves. By not keeping track of this, you may be giving your body more than it needs or can even digest.

Taking too much of a certain supplement can cause negative side effects. Dosing suggestions can vary based on weight, gender, diet, and age, among other factors. Moreover, dosing recommendations on labels may not correspond with what scientific studies have proven to be an appropriate amount for what you’re using the supplement for.

It’s also worth noting that recommended dosages are not usually tested on children, or women who are pregnant or breastfeeding.

Even dosages for the same type of herbal product can differ from manufacturer to manufacturer based on how the plants are grown, prepared, and extracted. As there are no “generic” equivalents of plant-based supplements, quality, safety, and efficacy can vary even if the bottle label advertises the same herb.

There are several ways you can find sources for dosing information. These include:

• traditional medicinal practices
• your doctor
• scientific studies
• manufacturer websites
• product labels

Tips for Finding Reliable Supplement Information

When seeking out sources, look for ones without commercial ties to the supplement market. These commercial ties can include manufacturer websites, vitamin store sales reps, in-home sales reps, or anyone else that may have a bias.

Instead, use sources like MedlinePlus, Office of Dietary Supplements,, and the Memorial Sloan Ketter Cancer Center’s About Herbs.

Dietary supplements can be a beneficial addition to your diet if you need to fill in some nutritional nooks and crannies. Herbal products may claim to be remedies for your aches and pains. Neither are risk-free.

Before purchasing a new supplement, herbal product, or vitamin, do your research or consult your doctor, pharmacist, or dietitian to determine whether it’s the best choice for you.

This article was originally published on