There’s no shortage of weight-loss supplements on the market claiming to make dieting a snap.

The problem is, supplement companies have a tendency to overstate—and occasionally downright lie about—how effective their supplements for weight loss are.

The truth is, there are many weight-loss supplements that actually work, but these are the exception, rather than the rule.

In this article you’ll learn the seven best supplements for weight loss, and three common weight-loss supplements you should definitely avoid.

You’ll also learn more about the best weight loss supplement for men and women, PCOS weight-loss supplements, weight loss supplements for menopause, and more.

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The 7 Best Supplements for Weight Loss

1. Caffeine

What is it?: Caffeine is a natural central nervous system (CNS) stimulant and is the most widely taken psychoactive drug in the world. 

Caffeine is most commonly sourced from coffee beans, but can also be found naturally in certain types of tea and cacao beans. 

How does it work?: When you consume caffeine, adrenaline is released by the body. This causes an increase in metabolic rate, which can speed up weight loss.

If you use caffeine regularly, however, this increase in metabolic rate lessens in intensity (you become tolerant to caffeine’s effects), which is why it’s not advisable to use caffeine continuously for multiple weeks if you want to use it as a supplement for weight-loss.

To maximize caffeine’s weight-loss benefits, use up to 500 milligrams once a week on your most difficult workout days, or 100-to-200 milligrams per day for one-to-two weeks at a time before stopping caffeine usage for an equal amount of time.

Is it safe?: Caffeine consumption is generally considered to be safe.

That said, if you consume too much caffeine you may experience side effects such as insomnia, upset stomach, fluctuating energy levels, heart palpitations or increased heart rate, anxiety, tremors, and headaches.

2. Yohimbine

What is it?: Yohimbine is a naturally occurring substance that’s found in several types of plants native to central and western Africa, including the bark of the yohimbe tree.

How does it work?: The details of how yohimbine speeds up fat loss are rather technical, but the gist is it “deactivates” a mechanism in fat cells that prevents them from being burned.

In a sense, yohimbine helps “take the brakes off” of fat loss so your body’s natural fat-burning chemicals can work more effectively.

(Or for the more scientifically-minded of you out there, it blocks alpha-adrenergic receptors then releases adrenaline from neurons.)

The cumulative effect of this is yohimbine increases fat-burning and thus aids weight loss.

Is it safe?: When taken in higher doses, yohimbine may contribute to anxiety or impulsivity. Thus, yohimbine is not recommended for people with anxiety or panic disorders.

Since research also shows it can increase blood pressure at high dosages, yohimbine is contraindicated for people with heart conditions.

For the rest of us, though, research shows that moderate doses of yohimbine are generally well tolerated.

3. Thai Ginseng

What is it?: Thai ginseng, also known as Kaempferia parviflora, is an herb native to Thailand that has traditionally been used to improve virility and physical performance and support weight management.

How does it work?: Thai ginseng works as a natural weight-loss supplement because it contains several active compounds known as methoxyflavones which . . .

  • Increase energy expenditure by causing an effect in fat cells known as uncoupling
  • Decrease fat storage by influencing a receptor known as PPARy

Is it safe?: One review study of Thai ginseng found you can use up to 1.35 grams per day without experiencing any adverse effects. This is significantly higher than the clinically effective dose of between 90 and 180 milligrams per day found in most safe weight-loss supplements.

4. Grains of Paradise

What is it?: Grains of Paradise is the common name for the plant Aframomum melegueta, which is a herb in the ginger family that’s commonly used as a spice.

How does it work?: It contains various compounds like 6-gingerol and 6-paradol that can increase the metabolic rate by influencing receptors on fat cells involved in energy regulation and perception of temperature.

That’s why research shows that supplementation with Grains of Paradise increases energy expenditure (to the tune of about 100 calories per day) and reduces visceral fat levels.

Is it safe?: Research shows that Grains of Paradise is safe to use as a healthy weight-loss supplement unless you take doses that far exceed the clinically effective dose of around 30 milligrams.

5. Forskolin

What is it?: Forskolin is a substance found in the Indian herb Coleus forskohlii, which has long been used in Ayurvedic medicine to treat heart and respiratory disorders.

How does it work?: Supplementation with forskolin increases blood plasma and intracellular levels of a molecule known as cAMP (cyclic adenosine monophosphate), which stimulates the production of cellular energy.

This is why research shows that supplementation with forskolin accelerates fat loss and appears to increase testosterone levels as well.

Is it safe?: Most studies show that forskolin is very safe to take. That said, in some rare cases people supplementing with forskolin have reported experiencing side effects such as diarrhea, nausea and vomiting, constipation, headache, and fatigue.

6. Fucoxanthin

What is it?: Fucoxanthin is a vitamin A-like molecule known as a carotenoid that’s found in seaweed (and that gives brown seaweed it’s color)

How does it work?: Fucoxanthin enters fat cells and produces an effect known as uncoupling. This increases the amount of energy that mitochondria burn which can accelerate weight loss.

Additionally, studies show that it can also hinder fat storage by inhibiting the absorption of glucose into fat cells and increasing its uptake into muscle cells.

(Funny side note: it was once thought that fucoxanthin could convert white fat into brown fat but researchers had simply forgotten that fucoxanthin was just a brown pigment making it look different.)

Is it safe?: Several studies show that fucoxanthin is safe to use and has no adverse side effects.

7. 5-HTP

What is it?: 5-HTP is a compound produced by the metabolism of the amino acid tryptophan, which is found in foods like milk, meat, potatoes, pumpkin, and various greens.

It’s converted into serotonin in the brain, which is one of the principal neurotransmitters involved in feelings of happiness.

How does it work?: When you diet to lose weight, your body produces hormones that make you feel hungry.

5-HTP makes this list of top weight-loss supplements because it helps to nullify these hormones, which increases feelings of fullness, helps control food intake, and curbs cravings for carbohydrates, all of which help you lose weight. 

Is it safe?: 5-HTP is safe to take for most people, though if you take very large doses (600 milligrams per day or more) some may experience side effects including nausea, insomnia, diarrhea, stomach pain, and amenorrhea.

It’s also recommended that you steer clear of 5-HTP if you are taking medication that increases serotonin levels (such as antidepressants or prescription painkillers) as this can make the serotonin levels in your body dangerously high.

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The 3 Worst Supplements for Weight Loss

1. Hoodia

Hoodia is a cactus-like plant that grows in Africa’s Kalahari Desert. Historically, the San Bushmen ate hoodia when food and water were scarce to mitigate thirst and hunger pangs.

Several studies show, however, that hoodia is not only an ineffective supplement for weight loss, in many cases it’s dangerous.

Hoodia gordonii is a top three fat loss failure since it actively harms you and, despite that, doesn’t even have the common courtesy to help you lose fat.

2. Conjugated Linoleic Acid (CLA)

Conjugated linoleic acid (CLA) is a fatty acid found in meat and dairy.

Research shows that CLA may . . .

 . . . and yes, you read that right—despite having tons of data to work with, no one really knows what effect CLA will have on you until you take it.

And that’s why it makes it to our top three worst supplements for weight loss. It’s unreliable and inconsistent in its effects (and most data shows it’s a dud).

3. Garcinia Cambogia

Garcinia cambogia is a small yellow fruit that’s widely used in natural weight-loss supplements.

The reason it’s on this rogue’s gallery of supplements for weight loss is there isn’t enough convincing evidence that it helps you lose weight (and that’s kind of a prerequisite for being included in the best weight-loss supplements section).

That is, for every study that shows it can help you lose weight, there’s another that shows it’s not worth a plugged nickel.

Don’t waste your money gambling on something that may or may not help you reach your weight-loss goals—stick to one of the top weight-loss supplements listed above instead.

FAQ #1: What are the best weight-loss supplements for women?

Many supplement companies sell weight-loss supplements that they claim are designed specifically for the female body.

This, however, is utter bunk. 

The underlying mechanism of fat loss is the same for men and women, which means the supplements that speed up the process are the same whether you’re male or female.

As such, the supplements discussed in this article are the best weight-loss supplements for women (and the best weight-loss supplements for men, too).

If you’re looking for a medically-proven weight-loss supplement that combines clinically effective doses of many of the ingredients above, then check out Legion’s 100% natural fat burner, Phoenix.

(Or if you aren’t sure if Phoenix is right for you or if another supplement might be a better fit for your budget, circumstances, and goals, then take the Legion Supplement Finder Quiz! In less than a minute, it’ll tell you exactly what supplements are right for you. Click here to check it out.)

FAQ #2: What are the best weight-loss supplements for men?

Many supplement companies sell weight-loss supplements that they claim are designed specifically for the male body.

This, however, is complete tosh. 

The underlying mechanism of fat loss is the same for men and women, which means the supplements that rev the process in men are the same as those that speed up fat loss in women.

As such, the supplements discussed in this article are the best weight-loss supplements for men (and the best weight-loss supplements for women, too).

FAQ #3: What are the best PCOS weight-loss supplements?

Polycystic ovary syndrome (PCOS) is a condition that causes a woman’s ovaries or adrenal glands to produce higher-than-normal amounts of male hormones. It also causes cysts to grow on the ovaries. 

One of the most common symptoms of PCOS is weight gain, and one of the best ways to improve all PCOS symptoms is to lose weight

This leads many women with PCOS to seek out quick weight-loss supplements that will help them get their condition under control. 

Unfortunately, no amount of weight loss pills and powders are going to magically improve the symptoms of PCOS. The good news, however, is that if you know how to eat and train to drive fat loss, certain supplements can help.

Aside from the supplements already discussed in this article, some supplements that may help women with PCOS lose weight are:

  • Inositol: Inositol, also known as myo-inositol, is a carbocyclic sugar that is found in tissues throughout the body. Several studies show that inositol is effective at improving insulin sensitivity and lowering blood pressure in women with PCOS, which may aid weight loss.
  • Omega-3 Fatty Acids: Omega-3 fatty acids are a type of fat found in foods such as fish and flaxseed, and in dietary supplements such as fish oil. Research shows that omega-3 fatty acids may help to improve insulin sensitivity in women with PCOS which should make losing weight easier. 

(And if you’d like to try a high-potency, molecularly distilled fish oil with added vitamin E and lemon oil to prevent oxidation, rancidity, and “fish oil burps,” try Legion’s fish oil supplement, Triton.)

  • Protein powder: Studies show that women with PCOS who eat a high-protein diet are better able to manage their weight than those who eat a low-protein diet. While you should get most of your daily protein from nutritious foods, protein powder is a convenient and practical way to boost your protein intake that may help you lose weight as part of a calorie-controlled diet. 

(And if you want a clean, all-natural, delicious tasting whey protein isolate that’s naturally sweetened and flavored and free of chemicals, GMOs, and hormones, then you want WHEY+.)

Finally, if you’d like specific advice about what diet to follow to reach your fitness goals, take the Legion Diet Quiz.

FAQ #4: What are the best weight-loss supplements for menopause?

It’s common for women to gain weight around the time of the menopause.

This is mainly due to the changes that take place in the body at this time, such as hormonal fluctuations, decreased muscle mass, and increased insulin resistance.

Sadly, no supplement can make you lose weight during or after menopause on its own. To lose weight and maintain your health during menopause—or any stage of life for that matter—the best things to do are:

  1. Use an aggressive (but not reckless) calorie deficit of 20-to-25%.
  2. Eat a high-protein diet.
  3. Do resistance training

Assuming you have these in place, though, taking proven weight-loss supplements can help speed up the fat loss process.

FAQ #5: Can I take weight-loss supplements while breastfeeding?

I wouldn’t recommend it.

There’s very little research on whether it’s safe to take weight-loss supplements while breastfeeding. Thus, as a precaution, it’s best to avoid them until you’ve finished nursing.

+ Scientific References