Despite being banned and reformulated twice, Hydroxycut regained its spot among the most popular weight loss supplements. Newer formulas proclaim added benefits, such as boosting energy and mental focus. Although the ingredients previously linked to serious adverse effects have been removed, the resulting products are still not side-effect free. We explore the ingredients behind Hydroxycut so you know what to expect.
What Is Hydroxycut?
Hydroxycut is a popular brand of dietary supplements for weight loss. In 2008, they sold 9 million products in the US alone. The company that originally developed Hydroxycut (MuscleTech) was bought by Iovate Health Sciences and incorporated as a brand [R].
As a supplement, Hydroxycut is subject to looser regulations. Since the effectiveness and safety of supplements doesn’t need to be determined before marketing, the FDA can ban them only if they turn out to be unsafe. Hydroxycut has been banned and changed twice, after being associated with an increased risk of heart disease in 2004 and liver damage in 2009 [R+, R+, R, R].
Currently, the main active compound in this product is caffeine. Iovate Health Sciences sells 15 different Hydroxycut products for weight loss and sports performance enhancement. Some claim added benefits such as boosting mental focus (Hydroxycut HD), supporting hair, skin, and nail health (Hydroxycut Max! For Women), or improving digestion (Hydroxycut Platinum).
Evolution of Hydroxycut Components
The original Hydroxycut formulation contained [R+]:
- Hydroxagen (a blend with hydroxycitric acid from Garcinia Cambogia, Gymnema, soy lecithin, and Rhodiola)
- Guarana extract (with caffeine)
- Ephedra extract, now banned in the US*
- Willow bark extract
- Chromium picolinate
*In a study of 140 severe intoxication cases caused by dietary supplements, 62% were due to ephedra. Ephedra contains the stimulants ephedrine and pseudoephedrine. The most common adverse effects included [R]:
- High blood pressure (20%)
- Irregular heart rate (15%)
- Stroke (11.5%)
- Seizures (8%)
Of these, 15% resulted in permanent disability and 10% in death. This caused the FDA to ban a dietary supplement ingredient (ephedra) in 2004, for the first time in its history [R].
Hydroxycut was reformulated shortly after and launched onto the market again. The new version contained [R]:
- Calcium and potassium hydroxycitrate
- Chromium polynicotinate
- Plant extracts (Garcinia cambogia, Gymnema, and Rhodiola)
- Soy phospholipids
- Green, white, and oolong tea
For this reason, the FDA warned consumers to stop using Hydroxycut in 2009 but the manufacturer decided to give reformulation another go.
In the new Hydroxycut formulations, Arabica and Robusta coffee extracts are the main ingredients. Arabica coffee is rich in caffeine, while robusta coffee also provides chlorogenic acids.
All other ingredients are allegedly completely new and greatly vary among different Hydroxycut products. The compounds found in some but not all products include:
- Yohimbe bark extract
- Apple cider vinegar
- Ashwagandha leaf and root extract
- Various fruit and herbal extracts (such as Ginger, Cinnamon, Banaba, Griffonia, Raspberry Ketones, Quercetin)
- Alpha lipoic acid
- Soy Phospholipids
- Amino acids
Snapshot of Hydroxycut
- Several ingredients have proven weight-loss and energy-boosting effects
- Easy to take
- Most products are enriched with vitamins and amino acids
- More effective for weight loss in lean than overweight people
- Should be avoided by people sensitive to caffeine
- The effects of caffeine decline after long-term intake
- The amounts of many ingredients are not disclosed
- Multiple adverse effects described
How Does Hydroxycut Work?
Adenosine induces sleepiness while caffeine blocks adenosine receptors, preventing the activation of an enzyme that breaks down cAMP (phosphodiesterase). Increased cAMP enhances fat breakdown and the fight-or-flight response. However, long-term caffeine intake triggers increased production of adenosine receptors, eventually causing tolerance [R+, R+, R, R].
Green coffee is very rich in a class of polyphenols called chlorogenic acids. They increase fatty acid breakdown, reduce fat production, uptake, and digestion, and lower blood sugar and fats (triglycerides, cholesterol, free fatty acids, and LDL-cholesterol) [R, R, R, R, R, R+, R+].
Yohimbine is the active compound of yohimbe bark extract. Yohimbine increases adrenaline and dopamine while reducing serotonin levels (by blocking alpha-1 and alpha-2 adrenoreceptors). In addition to lowering blood sugar and increasing blood pressure, this promotes fat burning [R, R+, R].
Health Benefits of Hydroxycut
There are no studies directly testing Hydroxycut products. However, several studies investigated the effects of its main ingredients and similar supplements.
1) Hydroxycut May Help Lose Weight
Hydroxycut’s main active ingredient is caffeine, a well-known metabolic booster. In 12 clinical trials on 135 people, caffeine (100 – 600 mg/day) increased energy use and fat burning. Paradoxically, the effects were more pronounced in lean than in overweight people [R+, R, R, R, R, R, R, R, R].
The effect of caffeine on food intake is more controversial. Caffeine reduced food intake in 3 clinical trials on 65 people but not in 2 on 28 people. Caffeine didn’t help 33 women lose weight, but partially prevented weight regain by increasing carb over fat intake. On the contrary, caffeinated drinks (110 mg/L) increased the intake of sugary drinks in another 123 people [R+, R, R, R, R, R, R].
A decaffeinated green coffee extract supplement rich in chlorogenic acids enhanced the effects of a low-calorie diet in a clinical trial on 50 people and increased fat breakdown in cells. Similarly, decaf coffee enriched with chlorogenic acids reduced sugar absorption in the gut, enhancing weight loss in 2 trials on 24 people [R+, R, R].
Chlorogenic acids purified from green coffee (400 mg 3x/day) reduced weight, blood fats, and sugar intolerance in a trial on 30 pre-diabetic people. In obese mice, they prevented fat buildup and weight gain [R, R].
To sum it up, caffeine, chlorogenic acids, and Yohimbine in Hydroxycut may enhance weight loss, but the evidence is not convincing.
2) Hydroxycut May Boost Energy
Caffeine is the only component in Hydroxycut that may boost energy levels.
In clinical trials on over 100 people, all caffeine doses (3 – 13 mg/kg) enhanced aerobic exercise, such as cycling, running, rowing, and skiing. Caffeine acts by reducing the perception of fatigue and muscle pain, but the effects are less marked in people used to it (meta-analysis of 21 studies and trials on >89 people) [R, R, R, R, R, R, R, R, R, R, R, R, R, R, R, R+].
3) Hydroxycut May Enhance Strength Performance
In clinical trials on 67 men, caffeine improved strength performance (weight lifting and muscle extension/flexion). Moderate doses (3 mg/kg) were sufficient to boost high-speed exercise with low weights, but higher weights required high doses of up to 9 mg/kg in a trial on 13 men [R, R, R, R, R, R].
4) Hydroxycut May Increase Cognitition
Although Hydroxycut is primarily used for weight loss, some of its ingredients may also enhance cognition. In fact, some Hydroxycut products are specifically formulated to give a nootropic boost. Two ingredients potentially carry these effects: caffeine and ashwagandha.
Caffeine is one of the oldest known and most (ab)used cognitive enhancers. In clinical trials on almost 100 people, caffeine (100 – 400 mg) improved attention, alertness, reaction time, and perception. It may also improve passive learning on tasks that modestly rely on short-term, working memory [R, R, R, R, R].
Caffeine may partially compensate for the detrimental effects of sleep deprivation on brain function. In 3 clinical trials on 90 sleep-deprived people, caffeine (100 – 800 mg) preserved attention, alertness, reaction time, and logical reasoning better than placebo. Obviously, it acts only as a short-term band-aid solution in such cases [R, R, R].
Ashwagandha extract is an ingredient of some Hydroxycut products that may also enhance brain function. In 2 clinical trials on 70 people, ashwagandha root and leaf extract (600 – 1,000 mg/day) improved reaction time, attention, alertness, information processing, and memory [R, R].
In rare cases, the new Hydroxycut formulations have been reported to cause:
- Heart attacks and increased heart rate [R, R, R]
- Liver damage and failure [R, R+, R]
- Inflammatory bowel disease [R, R]
- Muscle breakdown (rhabdomyolysis) [R]
- Mania [R+]
- Reversible narrowing of brain arteries [R]
As the main active ingredient of Hydroxycut, caffeine is responsible for the majority of potential side effects, such as [R+]:
- Insomnia, anxiety, nervousness, and restlessness
- Increased heart and breathing rate
- Increased blood pressure and reduced blood vessel elasticity
- Diarrhea, vomiting, and stomach irritation
- Increased urination
- Muscle twitching
Caffeine reduces insulin sensitivity in healthy, obese, and diabetic people, which can lead to high blood sugar levels. Chlorogenic acids have the opposite effect and may reduce this risk in people taking Hydroxycut products that contain both [R, R, R, R, R, R, R].
Importantly, most of the desired effects of caffeine decrease in people consuming high amounts. This may cause people to gradually increase caffeine intake as they gain tolerance to its effects, triggering addiction. In people addicted to caffeine, drastically reducing caffeine consumption may cause withdrawal symptoms such as [R]:
- Decreased focus and alertness
- Anxiety and irritability
- Digestive issues
The amount of caffeine in Hydroxycut products is relatively high (most of them contain 200 – 270 mg per serving = ~3 cups of coffee), so long-term use or high doses may cause both side effects and withdrawal symptoms.
Chlorogenic acids seem to be relatively safe and caused no side effects in a clinical trial on 26 people taking green coffee extract (140 mg/day chlorogenic acids) to reduce blood pressure [R].
High chlorogenic acids (5.5 mmol) raised blood homocysteine (a risk factor for heart disease) in a trial on 20 people. However, Hydroxycut products contain chlorogenic acids in much lower amounts (approximately 0.25 – 0.5 mmol) [R].
Yohimbine must be used with caution (recommended dose 5.4 mg 3x/day) because high doses can be toxic to the brain (over 200 mg) and megadoses deadly (over 5,000 mg). Side effects of yohimbine intoxication include [R, R+]:
- High blood pressure and heart rate
- Anxiety and restlessness
- Drowsiness and confusion
- Increased urination
- Nausea, diarrhea, and lack of appetite
- Tremors and seizures
- Prolonged erections
- Unconsciousness and even death
Due to their potential for toxicity, yohimbine-containing supplements are banned in Canada, Australia, the Netherlands, and the United Kingdom [R+].
Among Hydroxycut products, Hydroxycut Hardcore Elite contains the highest amount of yohimbine (3.38 mg per serving). Since the dose is still very low, serious yohimbine adverse effects are unlikely in people taking this product.
Limitations and Caveats
Although multiple studies looked into the effects of different active compounds (especially caffeine), most of them were very small. Trials with larger populations are required to validate the results.
Studies on the effects of caffeine on exercise performance either used only men or didn’t distinguish between men and women, so data on sex-specific responses are lacking.
The studies investigating the effects of caffeine on food intake and yohimbine on weight loss had conflicting results.
The studies using other commercial supplements similar to Hydroxycut usually included employees of the manufacturing company among the authors, indicating a high risk of bias.
The potential drug interactions between caffeine and other drugs are complex. Consult your doctor if you plan to take Hydroxycut and take prescription medication (especially antibiotics).
- Antibiotics (enoxacin, pefloxacin, ciprofloxacin)
- Antidepressants (fluvoxamine, fluoxetine, paroxetine)
- Antifungal drugs (terbinafine, ketoconazole, fluconazole)
- Antipsychotics (clozapine, olanzapine)
- Bronchodilators (furafylline, theophylline)
- Drugs for irregular heart rate (mexiletine, propafenone, verapamil)
- Drugs for skin conditions/psoriasis (methoxsalen, methoxypsoralen)
- Drugs for heartburn (cimetidine)
- Muscle relaxants (idrocilamide)
- Birth control pills (ethinylestradiol, estradiol)
Although caffeine has slight antibacterial activity itself, it can reduce the effect of some antibiotics (chloramphenicol, tetracycline, benzylpenicillin, ciprofloxacin, nalidixic acid, erythromycin, metronidazole) and may increase the effect others (carbenicillin, ceftizoxime, gentamicin, kanamycin) [R+, R+].
Additionally, caffeine may enhance the effect of the following drugs by decreasing their elimination [R+]:
- Clozapine, an antipsychotic
- Riluzole, used to treat amyotrophic lateral sclerosis
Caffeine may enhance the action of some drugs with similar effects, such as:
- Stimulants (ephedrine, amphetamines, cocaine, phenylpropanolamine, tranylcypromine) [R, R, R, R, R+]
- Blood thinners (warfarin, clopidogrel, dalteparin, aspirin) [R, R, R]
In turn, caffeine may reduce the effects of:
- Sleeping pills (triazolam, midazolam, zopiclone, diazepam, and pentobarbital but NOT zolpidem) [R, R, R+, R, R]
- Antidiabetic drugs (insulin, glimepiride, metformin, rosiglitazone) [R+]
Both caffeine and alcohol compete for blocking adenosine receptors. Although this combination may reduce some unwanted effects of alcohol and caffeine, it can cause people to take higher amounts to achieve the wanted effects, increasing the risk of addiction. Caffeine also enhances the addictive potential of alcohol (by blocking A2A receptors) [R].
Chlorogenic acids may enhance the blood sugar-lowering effects of antidiabetic drugs such as metformin and thiazolidinedione. Although their concentration in Hydroxycut products is very low, diabetic people should consult their doctor before taking these supplements [R, R].
Yohimbine may enhance the action or side effects of some drugs such as:
- Stimulants (atomoxetine, amphetamines) [R, R]
- Some antidepressants (duloxetine, fluoxetine, tranylcypromine) [R, R+]
- Drugs for opioid overdose (naloxone) [R]
In turn, it may reduce the effects of:
- Anti-anxiety drugs (diazepam, ondansetron) [R]
- Some antidepressants (amitriptyline, imipramine) [R]
- Sedatives (xylazine) [R]
- Drugs for high blood pressure (amiloride, clonidine, guanabenz) [R, R]
Although the yohimbe bark extract content in Hydroxycut products is very low, people taking any of these medications and planning to use Hydroxycut supplements should consult their doctors.
Forms of Supplementation
Most Hydroxycut products come as capsules:
- Slow-release: Hydroxycut Ultra Lean, Hydroxycut Hardcore Elite Sports, Pro Clinical Hydroxycut Non-Stimulant, Slay, and Hydroxycut HD
- Rapid-release: Pro Clinical Hydroxycut, Hydroxycut Platinum, Hydroxycut Hardcore, Hydroxycut Max! For Women, Hydroxycut Black, Hydroxycut Hardcore Elite, and Hydroxycut Hardcore CLA Elite
Other forms of supplementation include:
- Rapid-release tablets (Hydroxycut Organic)
- Powder packets (Hydroxycut Drink Mix)
- Gummies (Hydroxycut Gummies)
Iovate Health Sciences recommends a dose of 2x/day for all Hydroxycut supplements. Depending on the product, this supplies 200 – 270 mg caffeine, 90 – 180 mg chlorogenic acids, and 1.2 – 3.38 mg yohimbine per day.
Although the official Hydroxycut website only shows positive reviews, those from independent websites include similar proportions of satisfied and unsatisfied customers.
Satisfied users reported weight loss and increased energy levels. They normally combined Hydroxycut with lifestyle changes such as doing more exercise or eating a low-calorie diet, so it’s difficult to estimate Hydroxycut’s contribution to the effects reported.
Some users stopped taking Hydroxycut after not noticing any effects and one even reported having gained weight. However, the main reason why some users gave Hydroxycut bad rating were the numerous side effects. Among them, the most common were stomach cramps, diarrhea, nausea, headache, jitters, tiredness, weakness, anxiety, and insomnia.
We at SelfHacked think there is much more to weight loss than multi-ingredient weight loss supplements. Learn more about various ways to lose weight here.
Although several ingredients in the new Hydroxycut formula offer weight loss and strength-building benefits, the evidence to support their use is not convincing. All in all, the new formulations probably do carry fewer risks. Their benefits are harder to tease apart, though, especially since many different nutrients and extracts of unknown quantities go into the final product.
The main active ingredient in the current products is caffeine, a well-known cognitive enhancer that doesn’t come without unwanted effects. Since the dose of caffeine in a serving of these products is equivalent to 3 cups of coffee, the caffeine alone is enough to give you a surge of energy. For this same reason, people sensitive to the effects of caffeine, or those with anxiety or heart disease, should avoid Hydroxycut. Caffeine-free formulas are also available.
When it comes to weight loss, we consider that a well-rounded exercise program and a healthy diet are the best way to go. Supplements can be beneficial for some people, but picking a couple of well-researched synergistic compounds will usually be more effective than to-be-established multi-ingredient formulas.