Buyer's checklist
How to Choose a Weight-Loss Supplement
Read the label before the ad. Check that every ingredient has a known amount, compare those amounts with research doses, and walk away from any promise of fast loss without diet or exercise. Look for a named maker and real test reports, and show the bottle to your pharmacist. Most products, Slim Metrix included, fail at least one check.
Written by the Slim Metrix editorial teamUpdated
The checklist
How do you choose a weight-loss supplement?
Ask ten questions before you pay. We answered them for Slim Metrix to show the checklist on a real product.
| Question | Why it matters | Slim Metrix |
|---|---|---|
| 1. Does it promise fast loss without diet or exercise? | The FTC says that claim is always false (FTC: Gut Check on false weight-loss claims) | No such promise on the label; the sales page gives a 60-90 day timeline with no study behind it |
| 2. Is the product itself tested in a human trial? | Claims need competent and reliable evidence (FTC: Health Products Compliance Guidance) | No trial of the product |
| 3. Does every ingredient have an amount? | A blend hides single doses (FDA: labeling guide (proprietary blends)) | Only zinc and chromium; 8 ingredients share 276 mg |
| 4. Do the amounts match research doses? | Too little may do nothing; too much may harm | Berberine cannot reach study doses; chromium is about 143% of today's DV |
| 5. Is the %DV up to date? | Old reference values make amounts look smaller | Chromium printed 41.67%, based on an old DV |
| 6. Is a maker or distributor named? | Someone must answer for safety and the label (FDA: questions and answers on dietary supplements) | None named |
| 7. Is there a lab report for your batch? | Some products hide prescription drugs (NIH ODS: weight-loss supplements (consumer fact sheet)) | A reference code only; no report published |
| 8. Are the reviews checkable? | Fake reviews are banned (FTC: final rule banning fake reviews) | No verified reviews yet; we show none |
| 9. Is it safe with your medicines? | Supplements can interact (NCCIH: using dietary supplements wisely) | Several interactions; see the side effects page |
| 10. Can you get your money back? | A refund limits the cost of a test run | 60 days; containers must be mailed back at your cost |
FTC Gut Check
Which weight-loss supplement claims are always false?
The FTC names seven weight-loss claims that are always false. Among them: losing two or more pounds a week for a month without diet or exercise, and losing a lot of weight no matter what you eat (FTC: Gut Check on false weight-loss claims).
Two more: no product causes weight loss that stays off after you stop it, and none works for every user. If an ad says any of these, stop reading.
The FTC also says health claims need competent and reliable scientific evidence, generally randomized controlled trials in people, and that customer testimonials are never enough (FTC: Health Products Compliance Guidance). A sales-page badge about studied ingredients does not meet that bar unless the product, at its own doses, was tested.
FDA warning signs
What are the FDA's warning signs of a health-fraud product?
FDA lists six tip-offs. Two or more is a reason to walk away.
One product does it all
It claims to fix weight, blood sugar, energy and mood at once.
Personal success stories
Testimonials stand in for evidence. They are easy to invent.
Quick fixes
Results in days, with no change in eating or activity.
"All natural"
Some "natural" products have secretly contained prescription drugs.
Too-good-to-be-true words
Talk of a secret formula or amazing, effortless results.
Conspiracy theories
Claims that doctors or drug companies are hiding the answer.
Source: FDA's six tip-offs to health-fraud scams (FDA: 6 tip-offs to health-fraud scams). Our red flags article shows each one in real ads.
Label reading
How do you read a proprietary blend on a supplement label?
Look at the total weight and the order. A blend label must give the total weight of its ingredients and list them from most to least by weight, but it does not have to give single amounts (FDA: labeling guide (proprietary blends)).
Slim Metrix is a good example. Its 276 mg blend holds eight ingredients, starting with alpha lipoic acid and ending with banaba (Slim Metrix label graphic). If split equally, each would be about 34.5 mg; the real split is not published. The first ingredient is the largest share and the last is the smallest.
Ingredients with a Daily Value, such as zinc and chromium, must be listed on their own with amounts. See every line on the Supplement Facts page.
Amounts vs research
How do you compare a supplement's doses with research?
Put the label amount next to the dose studies used. These bars do that for the four Slim Metrix amounts we can check.
Also check the %DV column. Slim Metrix prints 41.67% for chromium, which matches an old 120 mcg reference. Today's Daily Value is 35 mcg, so 50 mcg is about 143% (NIH ODS: chromium fact sheet).
Ad pictures
Can you trust the ingredient photos in supplement ads?
Not on their own. A photo shows what a designer chose, not what is in the capsule. Always check the picture against the label.
The Slim Metrix brand art has a clear example. One image file named for berberine shows turmeric, and turmeric is not in the formula. Another, named for cinnamon, shows matcha green tea; cinnamon is not an ingredient either. A scene photo surrounds the bottle with fruit, garcinia and green coffee beans, and only green tea from that scene is on the label.
Reviews
How can you tell if weight-loss supplement reviews are fake?
Often you cannot, which is why reviews should never decide a health purchase. The FTC says telling real reviews from fake ones can be nearly impossible (FTC: how to evaluate online reviews).
Check several sources, be wary of a burst of reviews in a short time, and look at a reviewer's history. Since 2024, an FTC rule bans fake and AI-written reviews, bought positive reviews and hidden insider reviews (FTC: final rule banning fake reviews).
The Slim Metrix sales page shows a star score, review counts and named testimonials that we cannot verify, so we do not repeat them. Our reviews page stays empty until reviews are matched to real orders.
Last check
How do you check a weight-loss supplement is safe with your medicines?
Take the bottle, not the ad, to your pharmacist. Ask about every ingredient on the label, including the ones the ad leaves out.
- Diabetes medicines: chromium may add to insulin or metformin (NIH ODS: chromium fact sheet).
- Transplant drugs and many common drugs: berberine may raise cyclosporine and tacrolimus levels and slowed three drug enzymes in people (MSK About Herbs: berberine).
- Liver history: green tea extract is a rare, known cause of liver injury (LiverTox: green tea).
- Pregnancy or breastfeeding: skip products with berberine (NCCIH: goldenseal and berberine).
The full list for Slim Metrix is on the side effects page. For the bigger picture on what works, read our weight-loss guide.
FAQ
Questions about choosing a weight-loss supplement
What should I look for in a weight-loss supplement?
Clear amounts for every ingredient, doses that match research, a named maker, a lab report for your batch and no promises of fast or effortless loss. Then check it with your pharmacist. Few products pass all of these; Slim Metrix fails on blend amounts, a named maker and test reports.
What is a proprietary blend?
A group of ingredients listed under one total weight, without single amounts. The label must list blend ingredients from most to least by weight (FDA: labeling guide (proprietary blends)). In Slim Metrix, eight ingredients share 276 mg, so no one can tell how much of each is in a capsule.
Are weight-loss supplements regulated by the FDA?
Only loosely. FDA does not approve supplements for safety or effectiveness before sale (FDA: what FDA does and doesn't approve). Makers and distributors are responsible for safety and truthful labels (FDA: questions and answers on dietary supplements). That is why the checks on this page fall to you and your pharmacist.
Is a natural weight-loss supplement always safe?
No. Natural does not always mean safe, and supplements can interact with medicines (NCCIH: using dietary supplements wisely). Green tea extract, a natural ingredient, is a well-established cause of rare liver injury (LiverTox: green tea). Some natural products have also hidden prescription drugs (FDA: 6 tip-offs to health-fraud scams).
What does an out-of-date %DV on a label mean?
The label uses an old reference amount, so the percentage is wrong for today. Slim Metrix prints 41.67% for 50 mcg of chromium, which matches an old 120 mcg value. Against today's 35 mcg Daily Value, it is about 143% (NIH ODS: chromium fact sheet).
Should I buy a supplement that says it works like a GLP-1 drug?
No. No supplement is a GLP-1 drug, and Slim Metrix is not one either. FDA warns that unapproved GLP-1 products are not reviewed for safety, effectiveness or quality (FDA: concerns about unapproved GLP-1 drugs). If you are interested in that medicine, talk with your doctor.
Who wrote this
Written and reviewed by
Plain-language pages built from the brand's label graphic, the sales page and linked medical sources.
Last updated . Read our editorial standards and how we check reviews. This website is run by a U.S. stocking partner for Slim Metrix, not by the manufacturer. We earn money when you buy through our order links.
Keep reading
More about Slim Metrix
Weight-loss guide
What works for weight loss, ranked by evidence, with a safe pace and where a supplement fits.
Read more
Supplement Facts
Every line of the Slim Metrix label typed out, with the chromium DV fix and what the label leaves out.
Read more
Reviews
Why no star score is shown yet, how each review is matched to a real order, and how to spot fake ones.
Read moreU.S. stocking partner for Slim Metrix
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