2025-03-01 · fat burners, thermogenics, caffeine, green tea extract, weight loss supplements, supplement safety, synephrine, yohimbine, DMAA

Updated 2026-07-28

Do fat burners actually work?

A little, and only some of them. Meta-analyses of the ingredients that carry a real signal — caffeine at 200–400 mg/day and green tea catechins (EGCG) around 300–500 mg/day — show roughly 1 kg of extra weight loss over placebo across 8–12 week trials, on top of a calorie-controlled diet. That is the ceiling for evidence-supported thermogenics. The extra ingredients that most 'fat burner' products layer on (synephrine, yohimbine, raspberry ketones, forskolin, garcinia cambogia) either add no benefit or add cardiovascular risk. No supplement produces GLP-1 magnitude weight loss, and any product promising rapid, dramatic results is either overselling caffeine or hiding an undeclared pharmaceutical.

Are fat-burner supplements safe?

The evidence-supported ingredients (caffeine at moderate doses, green tea EGCG under 800 mg/day, protein, fiber) are generally safe for healthy adults. The products marketed as 'fat burners' are a different story. Independent testing has repeatedly found that roughly 20–70% of weight-loss supplements in the tested pool contain undeclared drugs — sibutramine, phenolphthalein, fluoxetine, or diuretics — that were pulled from the U.S. market for cardiovascular events, cancer risk, or other harms. Synephrine, yohimbine, and DMAA carry documented cardiovascular events; DNP has caused fatalities. Anyone with hypertension, arrhythmia, anxiety, thyroid disease, or on any prescription should treat over-the-counter fat burners as a real risk category, not a wellness product.

What's the difference between caffeine and a 'fat burner' pill?

Mechanistically, very little. The measured energy-expenditure lift and appetite suppression in most 'thermogenic' blends comes from the caffeine content, sometimes stacked with green tea EGCG for a small additive effect. The other ingredients on the label — synephrine, yohimbine, raspberry ketones, forskolin, capsaicin, garcinia — either add nothing or add side effects. Two problems with the pill format: total caffeine is often 300–500 mg per serving (above the FDA's 400 mg/day general guidance), and proprietary blends hide the actual per-ingredient dose so you cannot compare it to a trial. Coffee delivers the same active ingredient with fiber, polyphenols, and water attached, at a fraction of the cost. See our [coffee and caffeine for weight loss](/weight-loss/coffee-caffeine-weight-loss/) guide for dosing detail.

Can I take fat burners with Ozempic or Wegovy?

Talk to your prescriber before you do, and default to no. GLP-1 medications already reduce appetite and slow gastric emptying, and adding stimulant-heavy fat burners can worsen the nausea, reflux, and constipation that GLP-1s cause, while also stacking cardiovascular risk from the caffeine and any synephrine or yohimbine. Fiber and protein supplements — the two Tier-A ingredients — are actually a reasonable adjunct with a GLP-1 (fiber helps with constipation, protein helps preserve lean mass during rapid weight loss). But 'thermogenic' fat burners are the wrong category to combine with a prescription weight-loss drug, and any 'natural GLP-1' or 'GLP-1 booster' supplement is marketing, not pharmacology.

Is green tea extract effective for weight loss?

Modestly. The Hursel 2009 meta-analysis in the International Journal of Obesity pooled 11 trials and found roughly 1 kg of extra weight loss over placebo with green-tea catechin supplementation, most reliable when combined with caffeine and in a caloric deficit. Below about 500 mg/day of EGCG the safety record is good. Above 800 mg/day of EGCG (a threshold set by the European Food Safety Authority in 2018) there are rare but documented cases of drug-induced liver injury, tracked by the U.S. Drug-Induced Liver Injury Network. Practically: 2–3 cups of brewed green tea per day (about 200–300 mg catechins) is the safest way to get the signal; concentrated 'fat burner' capsules that push EGCG past 800 mg cross into risk territory.

Are appetite suppressants like garcinia cambogia worth trying?

No — garcinia cambogia (hydroxycitric acid, HCA) is Tier C at best. Onakpoya's 2011 systematic review in the Journal of Obesity pooled 12 randomized trials and found the average extra weight loss was under 1 kg — statistically detectable, clinically negligible, and offset by hepatotoxicity case reports that led the FDA to issue warnings about specific garcinia-containing products. Raspberry ketones (Onakpoya 2013) have essentially no human evidence for weight loss at all. If your goal is appetite control, the honest options are glucomannan or psyllium fiber and a daily protein target of 1.6–2.2 g/kg — both covered in our [appetite-suppressant supplements](/weight-loss/appetite-suppressant-supplements/) and [fiber and protein supplements](/weight-loss/fiber-protein-supplements/) guides.

What ingredients should I avoid in a fat burner?

Actively avoid: DMAA (1,3-dimethylamylamine) and DMHA — amphetamine-like stimulants banned by the FDA in supplements but still appearing in pre-workouts and fat burners; DNP (2,4-dinitrophenol) — an industrial chemical marketed as a fat burner that has killed more than 60 people since 2007 by uncoupling mitochondrial energy production; ephedra (ma huang) — banned in the U.S. in 2004 after cardiovascular deaths; synephrine (bitter orange) — the most common ephedra replacement, with documented cardiovascular events; yohimbine at unstandardized doses — an alpha-2 antagonist with variable content that can trigger panic, hypertensive spikes, and arrhythmia; usnic acid — pulled from major brands after severe liver injury; and anything on the FDA's tainted weight-loss products database. Any 'proprietary blend' that hides per-ingredient doses is also a strong caution signal because it prevents you from checking any of these against label.

Do fat burners help you lose belly fat specifically?

No. Spot reduction — losing fat from a specific body region by targeting it with a supplement, exercise, or device — is not a real physiological phenomenon in adults. Fat loss happens in an order set by genetics, hormones, and body-fat distribution, and no ingredient in any fat burner selectively removes visceral or subcutaneous abdominal fat. Products marketing 'belly-fat burners' or 'targeted abdominal fat loss' are trading on a myth. What actually reduces visceral fat is an overall caloric deficit, regular resistance training to preserve lean mass, adequate protein, sleep, and — for people with clinical obesity — [prescription weight-loss medications](/weight-loss/prescription-weight-loss-medications/) or bariatric surgery. The visceral-fat signal from lifestyle change is real; the belly-targeted supplement signal is not.

Fat Burner Supplements: What Works, What Doesn’t, and What’s Dangerous

Fat-burner supplements are over-the-counter pills, powders, and stacks marketed to speed metabolism, suppress appetite, or block fat absorption. The evidence base is uneven: a few ingredients have small documented effects, several have safety concerns, and the FDA does not review supplements for effectiveness before sale — so buyer-beware framing matters more than usual here. This guide sorts the category by evidence tier, flags the ingredients with real cardiovascular or hepatic risk, walks through interactions with prescription weight-loss drugs, and translates third-party testing marks into what they actually cover.

Quick stats — fat-burner supplements

• FDA regulation posture: Supplements are regulated under the Dietary Supplement Health and Education Act of 1994 (DSHEA); the FDA does not review them for safety or effectiveness before market, and it can only pull products after real-world harm surfaces.
• Adulteration rate: Independent testing programs (Cohen 2015, JAMA Internal Medicine; FDA sampling) have repeatedly found undeclared pharmaceuticals in roughly 20–70% of tested “weight-loss” and “fat-burning” supplements, most commonly sibutramine (withdrawn 2010 for cardiovascular events), phenolphthalein (suspected carcinogen), fluoxetine, or diuretics.
• Average measured effect for evidence-supported ingredients: Caffeine plus green-tea catechin stacks lift daily energy expenditure by roughly 50–100 kcal/day and produce about 1 kg of extra weight loss over placebo across 8–12 week trials.
• Stimulant-related ER visits: DAWN (Drug Abuse Warning Network) and FDA MedWatch data attribute thousands of annual emergency-department visits to weight-loss supplements containing high-dose caffeine, synephrine, or undeclared stimulants.
• Fatality-associated ingredient: DNP (2,4-dinitrophenol), sold online as a “fat burner,” has been linked to more than 60 confirmed deaths worldwide since 2007.

Key takeaways

• Only four categories of fat-burner ingredient have consistent, replicated human evidence for a small effect: caffeine, green-tea catechins (EGCG), fiber, and protein.
• Several commonly sold ingredients — synephrine, yohimbine, DMAA, DMHA, DNP, ephedra — carry documented cardiovascular events, seizures, or fatalities and should be actively avoided.
• Adulteration is the defining safety problem of this category: roughly 20–70% of tested products contain undeclared prescription drugs, and the FDA’s tainted-products database lists more than 1,000 individual products.
• The FDA does not review supplements for effectiveness. “Clinically studied” is a marketing phrase, not an FDA designation.
• Third-party testing (USP, NSF, Informed-Sport, ConsumerLab) verifies identity and purity — it does not verify that the product actually causes weight loss.
• If you are on a GLP-1, phentermine, an SSRI, an MAOI, warfarin, thyroid replacement, or a stimulant for ADHD, do not add a fat-burner supplement without a prescriber conversation first.
• What actually moves the needle for fat loss is protein plus strength training plus a manageable caloric deficit plus sleep plus daily movement. Supplements are, at most, a small adjunct.

Who this is for / not for

Good fit if:

• You are considering a fat-burner product and want an evidence-first read before you buy.
• You want to compare a specific ingredient’s likely benefit against its safety record and drug interactions.
• You are already doing the diet and activity work and want to know whether a thermogenic adds a small edge or is a waste of money.
• You are on a GLP-1 or other prescription weight-loss medication and want to know which supplements are safe, which are additive, and which are frankly dangerous to combine.

Not a fit if:

• You have heart disease, uncontrolled hypertension, a history of arrhythmia, or a seizure disorder — stimulant-based fat burners are contraindicated.
• You are pregnant, breastfeeding, or planning pregnancy — most fat-burner ingredients have not been studied in these populations and several are actively contraindicated.
• You have anxiety or panic disorder — stimulant-heavy products commonly worsen symptoms, and yohimbine can trigger panic attacks.
• You are managing complex thyroid, liver, or kidney disease — interactions and hepatotoxicity risk are higher and merit clinician review before starting anything.
• You are looking for a pill that produces GLP-1 magnitude weight loss. It does not exist in this category.

What “fat burner” actually means

There is no regulatory definition of “fat burner.” It is a marketing umbrella that covers at least five distinct product types:

• Thermogenics — stimulant-based blends built around caffeine, often with green tea extract, synephrine, yohimbine, or capsaicin, marketed to raise resting energy expenditure and blunt appetite.
• Appetite suppressants — fiber, protein, glucomannan, 5-HTP, or garcinia cambogia blends marketed to reduce hunger and next-meal intake. Covered in detail in our appetite-suppressant supplements review.
• Carb blockers — white kidney bean extract (phaseolamin) or wheat amylase inhibitors marketed to reduce carbohydrate absorption. Very weak evidence.
• Fat blockers — chitosan and orlistat-adjacent products marketed to reduce dietary fat absorption. Chitosan evidence is weak; prescription orlistat is a different category covered in our prescription weight-loss medications guide.
• “Metabolism boosters” — a catch-all that overlaps thermogenics and often adds L-carnitine, chromium, CLA, raspberry ketones, or forskolin.

Because “fat burner” is a marketing category rather than a pharmacological one, evaluating any product requires reading past the label and looking at the individual ingredients, their doses, and their evidence tier.

The evidence tier framework

The framework below mirrors the tier system used in our weight-loss supplements overview and applies it specifically to fat-burner ingredients. Individual products often mix tiers.

• Tier A — modest but real effect, generally safe: caffeine, green-tea catechins (EGCG), and protein and fiber (satiety-based, covered in the fiber and protein supplements guide).
• Tier B — mixed evidence, generally safe at label doses: capsaicin/cayenne, L-carnitine (with a clean signal only in the specific subset of endurance-trained people).
• Tier C — weak or inconsistent evidence, mostly safe at label doses: CLA (conjugated linoleic acid), raspberry ketones, chromium picolinate, garcinia cambogia (HCA).
• Tier D — no meaningful evidence, safety concerns: synephrine (bitter orange), yohimbine, 7-keto DHEA, forskolin.
• Tier X — avoid: adulteration risk, banned status, or documented fatalities: DMAA, DMHA, DNP, ephedra, any product carrying sibutramine-adulteration risk, and anything on the FDA tainted weight-loss products list.

Treat this as a triage. If an ingredient is Tier D or X, the decision is made. If it is Tier A or B, the next questions are dose, formulation quality, and drug interactions.

Category-by-category evidence table

Deep-dive: the four ingredients with the best evidence

1. Caffeine (Tier A)

Caffeine is the single most-studied thermogenic ingredient. Astrup’s 1990 double-blind trial in The American Journal of Clinical Nutrition showed a 3–4% rise in resting energy expenditure from a single 100–200 mg dose, sustained for several hours. In real-world weight-loss maintenance data, Icken’s 2016 analysis in the European Journal of Clinical Nutrition linked higher habitual caffeine intake to better long-term weight-loss maintenance. The honest limits: the daily energy-expenditure lift from 200–400 mg is roughly 50–100 kcal, tolerance to the appetite and thermogenic effect develops within weeks, and pushing above the FDA’s 400 mg/day guidance produces insomnia, elevated blood pressure, and dependence without additional benefit.

For most people, 2–3 cups of coffee spread through the morning delivers the same 200–400 mg with fiber, water, and polyphenols attached, at a fraction of the cost of a “thermogenic” capsule. The coffee and caffeine for weight loss guide covers dose, tolerance, and coffee-versus-capsule tradeoffs in more depth.

2. Green tea catechins / EGCG (Tier A/B)

Green tea contains catechins — polyphenols dominated by epigallocatechin gallate (EGCG) — that inhibit catechol-O-methyltransferase (COMT), the enzyme that breaks down norepinephrine. The proposed mechanism is that prolonged norepinephrine signaling extends the thermogenic effect of caffeine. Hursel’s 2009 meta-analysis in the International Journal of Obesity pooled 11 randomized trials and found roughly 1 kg of extra weight loss over placebo with green-tea catechin supplementation, most reliable when combined with caffeine and in a caloric deficit. The green tea and EGCG for weight loss guide covers the dose-response curve, matcha and brewed-tea comparisons, and the drug-interaction picture in more depth.

The safety picture is dose-dependent. Below about 500 mg/day of EGCG the record is good. The European Food Safety Authority’s 2018 opinion set 800 mg/day of EGCG from supplements as the threshold above which drug-induced liver injury risk becomes measurable, and the U.S. Drug-Induced Liver Injury Network has tracked concentrated-extract cases at supra-therapeutic doses. Practical read: brewed green tea (2–3 cups/day, roughly 200–300 mg catechins) is the safest way to get the signal.

3. Protein (Tier A)

Protein is not a thermogenic in the fat-burner sense, but it is the highest-satiety macronutrient and it preserves lean mass during a caloric deficit — both critical to durable fat loss. Wycherley’s 2012 meta-analysis of 24 randomized trials showed roughly 0.8 kg more fat loss and 0.7 kg less lean-mass loss on high-protein energy-restricted diets versus standard-protein energy-restricted diets. A protein powder is not magic; it is a convenient way to close a protein gap on days you cannot get 1.6–2.2 g/kg from food. Full formulation, dose, and quality-marker detail is in the fiber and protein supplements guide, and daily targets are covered in protein intake for weight loss.

4. L-carnitine — a narrow win for endurance-trained deficit dieters

L-carnitine is the transporter that moves long-chain fatty acids into mitochondria for beta-oxidation. In the general population, meta-analytic evidence for L-carnitine as a weight-loss supplement is inconsistent (Pooranfar 2014 and later reviews show small, unreliable effects). The specific subset where the signal is more consistent is endurance-trained athletes in a deficit, where L-carnitine has been reported to modestly increase fat oxidation during prolonged exercise. Outside that context, L-carnitine is not a fat-burner. There is also a theoretical cardiovascular concern: gut microbiota metabolize L-carnitine into TMAO (trimethylamine N-oxide), which has been associated with elevated cardiovascular risk in observational data.

Deep-dive: the four ingredients worth avoiding

1. Synephrine (bitter orange, Citrus aurantium) — Tier D–X

Synephrine is the most common ephedra replacement and shows up in most “thermogenic” fat-burner blends. It is a beta-3 and alpha-1 adrenergic agonist that raises heart rate and blood pressure. Stohs’s 2012 review pulled together case reports of ischemic stroke, myocardial infarction, angina, arrhythmia, and QT prolongation associated with synephrine-containing supplements, often in combination with caffeine. The FDA MedWatch and DAWN systems have received adverse-event reports linking synephrine-containing products to emergency department visits for cardiovascular events. Avoid entirely if you have any cardiovascular history, are on MAOIs or SSRIs, or are stacking other stimulants.

2. Yohimbine — Tier D

Yohimbine is an alpha-2 adrenergic antagonist derived from the bark of Pausinystalia yohimbe. The pharmacological effect is real (it can raise catecholamine release and, in some studies, modestly increase fat oxidation), but the practical problems are severe. Cohen’s 2015 analysis of yohimbe supplements found that actual yohimbine content ranged from 23% to 147% of the labeled dose across products — meaning consumers cannot know what they are taking. At effective doses, yohimbine commonly triggers panic attacks, hypertensive spikes, tachycardia, and — in case reports — seizures. Anyone with anxiety or panic disorder, hypertension, or on SSRIs, MAOIs, or tricyclics should avoid it entirely.

3. DNP (2,4-dinitrophenol) — Tier X, fatalities documented

DNP is an industrial chemical marketed illegally online as a fat burner. It works by uncoupling mitochondrial oxidative phosphorylation: energy that would be captured as ATP is released as heat, dramatically raising metabolic rate and body temperature. The mechanism is real, but the therapeutic window is essentially zero — the same dose that produces “fat loss” produces hyperthermia, tachycardia, rhabdomyolysis, and multi-organ failure. The U.K. Food Standards Agency’s DNP surveillance identified more than 60 confirmed DNP-related deaths worldwide since 2007, including young adults in university and fitness communities. DNP is not a supplement; it is a poison sold as one. Never take it, and if a “fat burner” mentions “cellular metabolism uncoupling,” walk away.

4. DMAA (1,3-dimethylamylamine) — Tier X, banned

DMAA is an amphetamine-like stimulant that was widely used in pre-workouts and fat burners in the early 2010s. After multiple deaths, including U.S. military service members, the FDA declared DMAA an adulterated ingredient in 2013 and pursued enforcement against manufacturers. Despite the ban, DMAA — and its close analog DMHA — continue to appear in imported and marketplace-sold “fat burner” products, particularly those advertising extreme energy or focus. The associated adverse events include hypertensive crisis, cardiac arrest, and hemorrhagic stroke. Any product listing DMAA, DMHA, 1,3-dimethylamylamine, 2-aminoisoheptane, or geranium extract as a stimulant should be treated as unsafe.

Interactions with weight-loss medications and other prescriptions

Fat-burner ingredients frequently interact with common prescription medications. The table below covers the highest-yield combinations to raise with a prescriber or pharmacist.

If you are on any prescription for weight loss, thyroid, blood pressure, mental health, blood thinning, transplant, or diabetes management, the safest workflow is to bring the actual bottle to your pharmacist and read the ingredient panel out loud. Broader drug-safety framing is in the weight-loss drug safety guide.

Third-party testing: what each mark covers, what none of them do

Third-party testing is a partial fix for the fact that supplement manufacturing quality is uneven. It is essential in this category — but it verifies purity and identity, not effectiveness.

• USP Verified (United States Pharmacopeia) — the most rigorous of the widely used marks. Verifies ingredient identity, potency (label match), purity (heavy metals, pesticides, microbial contamination), and cGMP compliance. USP-verified products for weight-loss supplements are rare because most manufacturers do not submit to the review.
• NSF Certified / NSF Certified for Sport — verifies identity, potency, and purity, and additionally screens for over 280 substances banned by major sports organizations (including undeclared stimulants and diuretics common in fat-burner adulteration). NSF Certified for Sport is the most useful mark for fat-burner consumers because banned-substance screening captures the adulteration failure mode.
• Informed-Sport / Informed-Choice — batch-tested for banned substances, similar in scope to NSF Certified for Sport. Widely used by athletes.
• ConsumerLab.com — a subscription lab that independently tests and reports on products. Not a certification you look for on the label — you read their reports before buying.

What none of these marks cover: effectiveness. A USP-verified caffeine + garcinia + synephrine blend is a verified-purity version of a mostly-ineffective and partially-dangerous formulation. The mark tells you what is in the bottle; it does not tell you the bottle helps you lose weight.

Red flags in fat-burner marketing

Any single one of these should slow you down. Two or more, put the bottle back on the shelf.

• “Proprietary blend.” The label lists a total milligram number and the ingredients, but not the per-ingredient dose. Almost always used to underdose active ingredients and overdose cheap fillers.
• “Clinically proven” or “clinically studied” without a linked, publicly available trial. A named clinician or a vague “clinical study” is not a citation.
• Before-and-after photos. Federal law prohibits deceptive testimonials in advertising; enforcement is inconsistent.
• Celebrity endorsements — including “as seen on TV” — with no independent research.
• Rapid, dramatic weight-loss promises (“burn 20 lb of belly fat in 30 days,” “melt fat overnight”). Not physiologically possible from a supplement.
• Marketplace-only availability (Amazon third-party sellers, TikTok Shop, eBay, unfamiliar direct-to-consumer sites) with no clinical, pharmacy, or health-store presence. Higher rates of adulteration and counterfeiting.
• Aggressive auto-renew and free-trial-to-subscription mechanics. A signal that the product’s revenue depends on customer inertia rather than repeat purchase.
• Sold only through the manufacturer with no independent retailer carrying it. Reduces both accountability and the pool of independent reviews.

When to talk to a clinician before starting

Do not start a fat-burner supplement without a clinician conversation if any of the following apply:

• Uncontrolled hypertension, cardiac history, arrhythmia, or ischemic heart disease.
• Seizure disorder.
• Anxiety, panic disorder, or a history of PTSD.
• Pregnancy, breastfeeding, or planning pregnancy.
• Thyroid disease or take levothyroxine.
• Kidney or liver disease.
• On any prescription weight-loss medication (GLP-1s, phentermine, naltrexone-bupropion, orlistat).
• On an antidepressant, especially an MAOI or SSRI.
• On a stimulant for ADHD.
• Under 18.

Bring the actual bottle to the visit and read the ingredient panel out loud. Your pharmacist is often a better resource for interaction screening than the primary-care visit.

What actually moves the needle instead

Honest paragraph: the interventions that produce sustained fat loss are not on a supplement shelf. They are:

• A protein-forward diet with adequate daily intake (1.6–2.2 g/kg during a deficit) to preserve lean mass and blunt hunger — see protein intake for weight loss.
• Resistance training two to four times per week to preserve or build the muscle that keeps resting metabolic rate up during weight loss — see strength training for weight loss.
• A moderate, manageable caloric deficit — the calorie-restricted diets guide covers realistic deficits and how to sustain them.
• Daily walking — the highest-adherence movement pattern for most people and a durable driver of energy balance. Covered in walking for weight loss.
• Sleep — chronic short sleep raises appetite hormones (ghrelin, leptin dysregulation), which no fat burner reverses.

For people with clinical obesity, prescription weight-loss medications — particularly GLP-1s — produce 15–20% body-weight loss magnitudes that no supplement approaches. Supplements are, at most, a small adjunct to that foundation.

Sources at a glance

1. Astrup A, Toubro S, Cannon S, Hein P, Breum L, Madsen J. Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers. The American Journal of Clinical Nutrition 1990.
2. Hursel R, Viechtbauer W, Westerterp-Plantenga MS. The effects of green tea on weight loss and weight maintenance: a meta-analysis. International Journal of Obesity 2009.
3. Onakpoya I, Hung SK, Perry R, Wider B, Ernst E. The use of Garcinia extract (hydroxycitric acid) as a weight loss supplement: a systematic review and meta-analysis of randomised clinical trials. Journal of Obesity 2011.
4. Onakpoya I, Terry R, Ernst E. The use of raspberry ketones as a weight-loss supplement: a systematic review of clinical trials. Journal of Ethnopharmacology 2013.
5. Cohen PA, Bloszies C, Yee C, Gerona R. An amphetamine isomer whose efficacy and safety in humans has never been studied, β-methylphenylethylamine (BMPEA), is found in multiple dietary supplements. JAMA Internal Medicine 2015 (supplement adulteration).
6. Stohs SJ, Preuss HG, Shara M. A review of the human clinical studies involving Citrus aurantium (bitter orange) extract and its primary protoalkaloid p-synephrine. International Journal of Medical Sciences 2012.
7. Bui LT, Nguyen DT, Ambrose PJ. Blood pressure and heart rate effects following a single dose of bitter orange. Annals of Pharmacotherapy 2006; and Haller CA, Benowitz NL. Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. NEJM 2000 (ephedra safety history).
8. U.S. Food and Drug Administration. Tainted weight-loss products database (ongoing) and MedWatch adverse event reporting; European Food Safety Authority. Scientific opinion on the safety of green tea catechins 2018 (EGCG hepatic threshold).

Related on WeightFAQ

• Weight-loss supplements overview — the tier-A/B/C/D/X framework across all weight-loss supplement categories.
• Appetite-suppressant supplements — glucomannan, protein, and 5-HTP-based hunger-control options.
• Coffee and caffeine for weight loss — dose, tolerance, and coffee-versus-capsule tradeoffs.
• Fiber and protein supplements — the two Tier-A satiety categories in more depth.
• Prescription weight-loss medications — the GLP-1, phentermine, and orlistat category and how it compares.
• Weight-loss drug safety — how to evaluate any weight-loss product for safety and adulteration risk.