Review · Weight and metabolism

Metabo Drops review: can one drop in your coffee carry the research?

Metabo Drops is a liquid supplement you add to your morning coffee. The seller names six ingredients and lists 43 references. We checked the references, the serving size and the price. The serving size turned out to be the biggest question.

By Grant Whitaker, Editor · Updated October 23, 2026 · 20 studies checked on PubMed

Disclosure: this is an independent review. Stark Verve is paid a commission if you buy through our links. That does not change our scores.

What Metabo Drops is

Metabo Drops is a liquid dietary supplement sold through ClickBank on metabodrops.com. The bottle shown on the site reads "1 fl oz (30 mL)". The seller's FAQ says to mix "a single drop" into your coffee each morning, and calls the formula a "proprietary, patent-pending" serum that is tasteless and dissolves instantly. The site does not name the company behind it beyond the brand.

The sales page headline promises that one tasteless drop in coffee burns fat around the clock. Its story is that most Americans inherited a slow metabolism and that coffee, paired with "the right metabolic nutrients," can wake it up. The page addresses "women and men", and two of the three short testimonials shown are from women, but nothing in the formula is sex-specific.

If the ingredient list looks familiar, it is. The named ingredients match almost exactly those of FitSpresso, a coffee-timed capsule we reviewed earlier: chlorogenic acid, green tea, chromium, L-carnitine and L-theanine. Our FitSpresso review covers that product. The difference here is the delivery format, and that difference matters a great deal.

The label problem, and the size of a drop

We found no Supplement Facts panel anywhere on the sales page, the FAQ or the checkout pages. The page lists six "super-nutrients" and gives no amounts. The sixth, a "vitamin complex," is not broken down into individual vitamins. Without a label, nobody outside the company can check doses.

What we can do is simple arithmetic. A standard pharmacy dropper delivers drops of roughly 0.05 mL, about twenty drops per milliliter. Even if every bit of that drop were active ingredient, it would weigh somewhere around 50 milligrams. In reality a liquid supplement is mostly water, glycerin or another carrier, so the active content would be smaller still.

That ceiling explains most of our score. Here is what the trials behind these ingredients used each day:

There is a second puzzle. A 30 mL bottle at about twenty drops per milliliter holds around 600 drops. At one drop a day that would last well over a year, yet the packages are sold as if each bottle is a monthly supply (the old FAQ talks about "90 day" and "180 day" packages). Either the real serving is larger than one drop, or a bottle lasts far longer than the pricing implies. The sales page does not resolve this, and we would want the label to answer it before buying.

The ingredients next to the research

Chlorogenic acid: the best case, at coffee-sized amounts

Chlorogenic acids are polyphenols that coffee already contains. The most useful trial for this product gave 150 overweight Japanese adults instant coffee with either 369 mg or 35 mg of chlorogenic acids once a day for 12 weeks. The high-dose group lost more abdominal fat on CT scans (visceral fat area down 9.0 cm² versus 1.0 cm²) and slightly more weight ^[1]. Two small crossover trials in healthy men, using about 329 mg a day for four weeks, found higher fat use after meals ^{[2] [3]}. All three were run or funded by Kao, the company that makes the enriched coffee.

An older 30-person trial of an enriched instant coffee reported 5.4 kg versus 1.7 kg lost over 12 weeks ^[4], but a systematic review grading that era of green coffee research found all of the included trials at high risk of bias and called the evidence promising but of poor quality ^[5]. The pattern is consistent: modest effects at a few hundred milligrams a day. Ordinary coffee supplies some chlorogenic acid on its own, so the question is how much a single drop could add on top. We cannot know without a label, and the arithmetic above says not much.

L-carnitine: a real but small effect at gram doses

L-carnitine helps carry fatty acids into cells for energy. A meta-analysis of 37 randomized trials (2,292 adults) found about 1.2 kg more weight loss than control, with the largest effect near 2,000 mg a day ^[6]. A second meta-analysis of 43 trials found a similar 1.1 kg, mainly in people who were already overweight, and no change in waist size ^[7]. Those are gram-level doses. A drop-sized serving would be a tiny fraction.

Green tea (Camellia sinensis): small to no effect on weight

A respiratory chamber study in ten healthy men found that green tea extract with 90 mg EGCG and 50 mg caffeine, taken three times a day, raised 24-hour energy expenditure by 4% ^[11]. A cold-exposure study in eight young men used 1,600 mg EGCG with 600 mg caffeine ^[12]. Over longer periods, the Cochrane review of green tea preparations found that six trials outside Japan produced an average weight difference of 0.04 kg versus control, which the authors judged not clinically important ^[10].

Chromium: the one ingredient a drop could hold

Chromium is a trace mineral, so trial doses are in micrograms and could fit in a liquid drop. The evidence for weight is thin. A Cochrane review of nine trials (622 overweight adults) found about 1.1 kg more weight loss than placebo after 12 to 16 weeks, graded low quality, of debatable clinical relevance, and with no clear dose response ^[13]. We do not know the chromium form or amount in Metabo Drops.

L-theanine and the vitamin complex

L-theanine, an amino acid from tea, is studied for mood and focus alongside caffeine. In one crossover trial, 250 mg of L-theanine combined with 150 mg of caffeine improved several attention measures and alertness ratings compared with placebo ^[14]. A small trial that put 200 mg into a food found no change in blood pressure or heart rate ^[15]. Neither measured body weight. The "vitamin complex" is not itemized, so there is nothing to compare.

What the marketing claims, and what we could verify

"Metabolic inequality." The sales page says scientists coined this term in 2023 after analyzing 170 years of research, and that up to 80% of Americans inherited a slower metabolism. We searched PubMed for the exact phrase in titles and abstracts and found no match. We could not trace the 80% figure either.

The reference list. To its credit, the seller publishes 43 numbered references, which few products in this category do. Reading them on PubMed changes the picture, though. Reference 5 is a study of overweight cats ^[8]. Reference 7 is a study of mice on a high-fat diet ^[9]. Reference 12 tested 1,600 mg of EGCG in eight young men sitting in a cooling suit ^[12]. Several others, by their titles, studied people with diagnosed conditions rather than healthy adults. None of the 43 tests Metabo Drops itself.

"Faster absorption" and "patent-pending." The FAQ says the liquid absorbs better than powders and that the formula is patent-pending. We found no published comparison for this product and no patent number on the page. A pending application, if one exists, is not evidence that a formula works.

"Zero side effects reported" and "FDA approved facility." The FDA does not approve supplement facilities. It registers them and inspects against manufacturing rules, so we treat that wording with caution. A claim of zero side effects cannot be checked from outside.

Price, packages and refund policy

The order section on the main sales page offers three packages, each a one-time payment:

• 10 bottles: $29 each ($290 total), free shipping.
• 4 bottles: $49 each ($196 total), shipping shown at checkout.
• 2 bottles: $79 each ($158 total), shipping shown at checkout.

The page does not say how long a bottle lasts. Our package cards assume 30 days per bottle, based on the seller's own FAQ, but as noted above that sits oddly with a one-drop serving. The FAQ describes a 60-day money-back guarantee, while the site's terms say returned items and return shipping costs are the buyer's responsibility and the sales page refund note excludes shipping and handling. There is no smaller option than two bottles, so the minimum spend is $158 plus shipping.

Safety

Because the doses are unknown, safety can only be judged by ingredient. Green tea extract is the main one to watch. A systematic review of 159 human studies linked concentrated catechin products to liver problems in a dose-dependent way, mostly when taken as large bolus doses ^[16], and a United States Pharmacopeia review recommends taking green tea extract with food and stopping if signs of liver trouble appear, such as dark urine, abdominal pain or yellowing skin ^[17]. At drop-sized amounts the risk is likely low, but it is the same reason to avoid stacking several green tea products.

Medication interactions we verified on PubMed:

• Beta-blockers: in healthy volunteers, regular green tea cut blood levels of the beta-blocker nadolol by about 85% and weakened its effect on blood pressure ^[18].
• Thyroid medication: chromium picolinate reduced absorption of levothyroxine when taken together; the authors advise separating them by several hours ^[19].
• Blood thinners: a published case report described an interaction between L-carnitine and the anticoagulant acenocoumarol ^[20]. If you take warfarin or a similar drug, ask your doctor before adding carnitine.
• Diabetes medication: chromium and chlorogenic acid are sold for blood sugar support, so tell your doctor if you take glucose-lowering drugs.

Coffee itself adds caffeine, which can affect sleep, heart rhythm and blood pressure. Results vary from person to person. Talk to your doctor before starting any supplement if you take prescription medication, and get medical advice for unexplained weight gain or loss, which can have causes that need care.

What we liked and what gave us pause

Frequently asked questions

Where is Metabo Drops sold?

On the seller's website, through ClickBank. The affiliate terms forbid promotion on Amazon, eBay and similar marketplaces, so listings there may not be genuine or covered by the refund policy.

How much of each ingredient is in a drop?

The seller does not say. We could not find a Supplement Facts panel. If you buy, check the label on the bottle when it arrives and compare it with the trial amounts in our table.

Is Metabo Drops the same as FitSpresso?

The named ingredients are nearly identical, but one is a liquid drop and the other a capsule, and neither publishes doses. We cannot say whether the amounts match. See our FitSpresso review for that product.

Will it work for men over 50?

None of the trials we reviewed focused on men over 50, and none tested this product. The modest effects seen in the chlorogenic acid and carnitine research came from much larger amounts than a drop can hold. Results vary, and diet, activity and sleep matter more than any coffee additive.

Is it a subscription?

No. The seller's FAQ says every order is a one-time payment.

How we reviewed Metabo Drops

We read the sales page, its FAQ, the seller's 43-item reference list and the affiliate terms on metabodrops.com, and checked the checkout pages for each package. We found no Supplement Facts label, so we compared the named ingredients with human trials and systematic reviews we opened on PubMed, and estimated what a single drop can physically hold. We did not test the product on people, and nobody at Stark Verve is a medical professional. Read our editorial policy to learn how we choose and update reviews. Stark Verve earns a commission if you buy through our links; that never changes what we write about the evidence.