What supplement claims really promise, and what they don't

On nearly every supplement that promises to support something, there's a sentence in small type: "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."

Most eyes skip right over it. It's one of the most informative lines on the bottle, because it tells you what kind of claim you're reading. Here are the most common beliefs about supplement marketing, and the facts behind them.

Myth: If it's on a store shelf, the FDA approved it

Fact: Supplements don't go through FDA approval before they're sold. The FDA regulates their quality, safety and labeling, and the Federal Trade Commission monitors advertising, but a public health review described large enforcement challenges and oversight that falls short (Starr, 2015).

Many people don't realize this. In an experiment with 262 college students, participants weren't very knowledgeable about the FDA's role. When they were told directly that the FDA hadn't approved a supplement, they rated it as less safe, but not as less effective (Dodge and Kaufman, 2007).

Myth: "Supports digestive health" means it was shown to improve digestion

Fact: Words like "supports," "promotes," "maintains" and "helps" signal a structure/function claim. Companies are responsible for having evidence that the claim is truthful, but the FDA doesn't review that evidence before the product is sold. That's exactly what the small-print statement is telling you.

Supplements aren't allowed to make disease claims, such as treating IBS or curing bloating caused by a condition. If you see one, treat it as a warning sign about the company, not a bonus.

Interestingly, the same experiment found that the structure/function disclaimer lowered how effective people thought a supplement was, without changing how safe they thought it was (Dodge and Kaufman, 2007). So reading it does shift perception, just not in the direction many people expect.

Myth: "Clinically proven" means this product was tested

Fact: Sometimes it does. Often it refers to a study on one ingredient, at a different dose, in a different group of people or in a different form. "Clinically studied ingredients" is an even looser phrase. The useful question is always: which study, which ingredient, how much, and in whom?

Picture a trial that tested one probiotic strain at a set dose for eight weeks in adults with IBS. A product that contains the same strain at a fraction of that dose, mixed with five others, can still say it contains a clinically studied ingredient. Nothing on the label is false, yet the study says little about that bottle.

Myth: Natural means safe

Fact: Plants and natural compounds can be powerful, which is the reason people take them. In a US network that studies drug-induced liver injury, the share of cases attributed to herbal and dietary supplements rose from 7% to 20% between 2004 and 2013. Injury from supplements not used for bodybuilding occurred mostly in middle-aged women and led to death or liver transplant more often than injury from medications, 13% versus 3% (Navarro et al., 2014).

These cases came from specialized referral centers, so they don't show how common the problem is. They do show that "natural" and "harmless" aren't the same word.

Myth: A doctor's name or a wall of five-star reviews proves it works

Fact: "Doctor formulated" has no standard behind the phrase. It can mean one physician consulted on the formula, sometimes as a paid advisor. It doesn't mean the medical community endorses the product, and it isn't a substitute for evidence.

Reviews tell you how people feel, and feelings about supplements run strong. In national surveys, many users said they would keep taking supplements even if scientific studies showed them to be ineffective (Blendon et al., 2001). A review can't separate the product from a placebo effect, a symptom that was improving anyway or another change the person made at the same time.

A quick translation guide

• "Supports," "promotes," "maintains": a structure/function claim not reviewed by the FDA.
• "Clinically studied ingredient": look for the study, the dose and whether the product matches.
• "Pharmaceutical grade": not an FDA-defined category for supplements.
• "Detox" or "cleanse": no defined meaning, and rarely a specific toxin named.
• "Fast relief" for chronic symptoms: a reason for extra skepticism.

When a claim shouldn't replace a checkup

If a product promises to fix bloating that has become new and frequent, especially with early fullness, pelvic pain or urinary urgency, see a doctor before buying anything. The same goes for blood in your stool, unexplained weight loss or anemia. No label claim applies to those.

Sources

1. Starr RR. Too little, too late: ineffective regulation of dietary supplements in the United States. Am J Public Health. 2015;105(3):478-85. PMID 25602879
2. Dodge T, Kaufman A. What makes consumers think dietary supplements are safe and effective? The role of disclaimers and FDA approval. Health Psychol. 2007;26(4):513-7. PMID 17605572
3. Navarro VJ, Barnhart H, Bonkovsky HL, et al. Liver injury from herbals and dietary supplements in the U.S. Drug-Induced Liver Injury Network. Hepatology. 2014;60(4):1399-408. PMID 25043597
4. Blendon RJ, DesRoches CM, Benson JM, Brodie M, Altman DE. Americans' views on the use and regulation of dietary supplements. Arch Intern Med. 2001;161(6):805-10. PMID 11268222

This article is for general information and isn't medical advice. Talk to your healthcare provider or pharmacist before starting a supplement, especially if you have liver disease or take prescription medication.