Supplements are not medicines
Dietary supplements are not medicines. In the United States they are regulated as food rather than drugs, which means the FDA does not review them for safety or effectiveness before they go on sale, and manufacturers cannot legally claim a supplement treats, cures, or prevents any disease. Nothing on this page is a substitute for prescription treatment, and no supplement described here has been shown to produce the weight loss seen with semaglutide or tirzepatide. If you are considering a supplement — particularly alongside prescription medication — talk to a doctor or pharmacist first, because interactions are real and some ingredients are not appropriate for everyone.
The Checklist
1. Find the Supplement Facts panel — not the marketing copy
The panel is the regulated part. Everything else on the box is advertising. Read the panel first, then read the marketing and notice the gap between them.
2. Look for per-ingredient amounts
Every active ingredient should have a number next to it. If several ingredients are grouped under a “proprietary blend” with one combined weight, you cannot evaluate the product against research and neither can anyone else.
A practical heuristic: if the dose were impressive, it would be on the front of the box. Hidden amounts are usually hidden for a reason.
3. Compare the amount to the research dose
This is the step most people skip, and it is the one that decides whether a product can work.
| Ingredient | Typical research dose |
|---|---|
| Berberine | 900–2,000 mg/day, divided into 3–4 doses with meals |
| Dihydroberberine | 100–200 mg once daily |
| Supplemental fiber | 5–15 g/day |
| Psyllium | Several grams, dosed before meals in satiety research |
If a capsule contains berberine plus five other actives, arithmetic tells you it is not delivering 900 mg of anything.
4. For probiotics, check for CFU or AFU counts
Organism count is the dose. A probiotic that does not publish one is asking you to buy on trust. Also look for strain-level identification — genus and species at minimum, ideally the strain designation, because probiotic effects are strain-specific.
5. Look for third-party testing
NSF, USP, or a named independent laboratory program. This verifies identity, potency, and absence of specified contaminants. It does not verify efficacy. Given documented potency variability in some ingredients — berberine among them — it matters.
6. Read the “other ingredients” line
Capsule material (hypromellose is vegetarian, gelatin is not), fillers, flow agents, and any allergen statement. If you have significant allergies, the absence of an allergen statement is itself information.
7. Check the warnings
A thorough contraindication list is a good sign, not a bad one. It suggests the company thought about who should not take the product. A label with no warnings at all on a product containing live bacteria or botanical extracts is doing you a disservice.
Phrases That Mean Less Than They Appear To
- "FDA registered facility" — the site is on a list. Says nothing about the product.
- "Clinically studied ingredients" — a study exists on an ingredient somewhere, possibly at a dose this product does not contain.
- "Doctor formulated" — unregulated phrase, no standard behind it.
- "Natural" — legally near-meaningless, and not a synonym for safe. Berberine is natural and interacts with statins.
- "Proprietary blend" — you are not being told the doses.
- "Supports" — the legally required hedge. It is not a claim of effect.
The two-question test
How much of the active ingredient is in a serving? If the label will not say, put it down.
Is that amount within the range used in published research? If not, the research does not apply to what you are holding, however impressive the ingredient sounds.
Frequently Asked Questions
What is a proprietary blend and why does it matter?
A proprietary blend lists several ingredients with only a combined total weight, so you cannot tell how much of each you are getting. It is legal, and it is the most common way to make a formula look impressive without committing to a dose. If a product uses one for its key active ingredients, you cannot compare it against any research.
What do NSF and USP marks mean?
They indicate independent third-party verification that the product contains what the label says and is free of specified contaminants. They do not verify that the product works. In a category the FDA does not pre-screen, they are one of the few available quality signals.
Does "FDA registered facility" mean the FDA approved it?
No. Facility registration means the manufacturing site is on an FDA list. It says nothing about the product, its ingredients, or whether it works. It is one of the most commonly misread phrases in supplement marketing.
What claims are red flags?
Anything about treating, curing, or preventing a disease — those are illegal for supplements. Specific weight-loss figures. Before-and-after photos. "Nature\u2019s [drug name]" framing. And any claim of a guaranteed result, which no honest supplement can offer.
Related Reading
- Best GLP-1 supplements — our ranking, with the commercial disclosure
- Full supplement comparison
- All supplement reviews
- What GLP-1 medications actually cost
Medical Disclaimer
We're not doctors, and this article is for education only — it isn't medical advice. GLP-1 medications are prescription-only and require evaluation by a licensed healthcare provider. Individual results vary widely, and only a clinician who knows your history can determine what is safe and appropriate for you. See our full medical disclaimer.
Keep Comparing
Every provider we've researched, with published pricing, medication type, and what's actually included.
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