The 6 Best Weight Loss Supplements
Finding the best weight loss supplements can be challenging. Many food supplements in the United Kingdom aren’t classified as “medicinal products” and, therefore, aren’t regulated by the Medicines and Healthcare products Regulatory Agency (MHRA).
What’s more, many weight loss supplements have questionable science behind them.
Having said that, some supplements show promise, including magnesium, caffeine, green tea, protein, fibre, and vitamin B12.
We’ll discuss the best weight loss supplements, science-backed alternatives to consider, and what to look for when buying supplements.
What Are the Best Weight Loss Supplements?
Lots of weight loss supplements should be avoided. However, a few dietary supplements show potential. Here’s what might help.
1. Magnesium
Magnesium has important jobs in the body. It creates new proteins, regulates blood pressure, and helps keep blood sugar balanced, among other things.
Magnesium deficiency can lead to chronic low-grade inflammation, which is linked to:
Obesity
Diabetes
Sleep disorders
Depressive symptoms
Cardiovascular diseases
A 2023 study with 1,000 participants found that blood magnesium levels were inversely associated with fat mass. In other words, the lower the magnesium levels, the higher the fat mass.
This link was more pronounced for those who got enough sleep and didn’t have chronic health conditions like diabetes, depression, and high blood pressure.
Magnesium deficiency was common in the study, too. More than half of the participants had suboptimal magnesium concentrations.
So, magnesium supplements may help in your weight loss journey.
A 2020 systematic review and meta-analysis looked at 32 studies on magnesium supplements. The studies were varied. They lasted six to 24 weeks and compared doses of 48 to 450 milligrams (mg) a day.
The results found that magnesium supplements caused a “great reduction in BMI” — or body mass index. Supplements were found to be more useful for certain groups than others, though.
Overall, there wasn’t a significant change in body weight, waist circumference, waist-to-hip ratio, or body fat percentage. But in certain subgroups, there was a significant change in body weight and waist circumference for:
Participants with obesity
Those with high blood pressure
Participants with insulin resistance-related disorders
Those who were deficient in magnesium at the start of the experiment
Women
Magnesium supplementation may be especially crucial in women because they might need more magnesium during pregnancy. Also, certain conditions affecting women, like polycystic ovary syndrome (PCOS), can impair magnesium absorption.
Pros:
Magnesium deficiency is common and largely undiagnosed.
Sleep disorders and depressive disorders are linked to obesity and magnesium deficiency, so magnesium supplements may support weight loss in more than one way. More research is needed on this, though.
There’s some promising science behind magnesium supplements as a weight loss aid.
Cons:
Magnesium supplements may not be as beneficial for those without obesity, a magnesium deficiency, or certain health conditions.
Best for: Women and people with a magnesium deficiency or those with obesity, sleep disorders, depressive symptoms, or certain health conditions like diabetes and high blood pressure.
Final verdict: Magnesium supplements have been linked to reduced BMI, body weight, and waist circumference in women and those with obesity.
2. Caffeine
Can an extra cup of coffee in the morning help with your weight loss efforts?
Caffeine can act as an appetite suppressant and a thermogenic (something that increases heat production). It can also increase fat oxidation (when the body breaks down fats).
A 2018 systematic review and meta-analysis of 13 randomised controlled trials looked at more than 600 participants. The paper concluded that “caffeine intake might promote weight, BMI and body fat reduction.”
However, there aren’t many clinical trials on caffeine supplements for weight loss. More research is needed, especially since caffeine can range from a cup of coffee to supplements like green coffee bean extract or kola nuts.
Pros:
Caffeine intake has been linked to weight loss and a reduction in BMI and body fat.
It’s not just caffeine pills and coffee. Green tea has been linked to weight loss too.
Cons:
Side effects include nervousness, jitteriness, vomiting, and tachycardia (increased heart rate). And we all know what happens when you have caffeine too close to bedtime…hello, sleepless night.
Your body can develop a tolerance to the weight loss effects of caffeine.
While there’s some promising research, studies on caffeine for weight loss are short and use a combination of products, making it hard to compare results.
Best for: Those who don’t experience sleep problems or caffeine side effects.
Final verdict: Caffeine has been linked to weight loss, body fat loss, and a lower BMI, but more research is needed on caffeine supplements.
Weight loss your way
3. Green Tea
Green tea contains caffeine and catechins. These compounds can increase energy metabolism, which may promote weight loss. As mentioned, caffeine can suppress appetite and increase thermogenesis and fat oxidation, which may also help with weight loss.
From the research we have so far, green tea shows some potential.
A 2012 meta-analysis looked at randomised controlled trials involving people with overweight or obesity. In these studies, green tea preparations were compared against a control.
Green tea intake was linked to weight loss, lowered BMI, and reduced waist circumference. However, the results were small and not statistically significant.
A 2020 systematic review and meta-analysis looked at the effect of green tea supplements on people with obesity. Green tea was linked to a reduced body weight and BMI.
It was especially effective when participants took supplements for 12 weeks and the dosage was less than 500 milligrams a day.
Overall, the researchers said green tea could be combined with a balanced, healthy meal plan and regular movement to help manage obesity.
Finally, a 2023 systematic review and meta-analysis looked at 59 studies and found that body mass, body fat percentage, and BMI were reduced following green tea extract supplementation.
Pros:
High-dose green tea extract has been linked with a small amount of weight loss and reduced BMI and waist circumference.
Beyond weight loss, green tea has anticarcinogenic (cancer-preventing), anti-inflammatory, antimicrobial, and antioxidant properties.
It may also be good for heart disease and oral health.
Cons:
Green tea might not make that much of a difference for weight loss.
You could experience side effects like nausea, stomach discomfort, constipation, or increased blood pressure. These may be mild to moderate.
Some green tea extracts have been linked to liver damage.
Best for: Perhaps everyone, but especially those interested in the other health benefits of green tea.
Final verdict: Green tea supplements might lead to weight loss and a lowered BMI, but the changes may be small.
4. Protein
Protein might make you think of bodybuilders and gym goers, but the science on protein for weight loss is fairly solid.
Consuming more protein than the recommended dietary allowance can:
Decrease fat mass
Reduce body weight
Preserve fat-free mass (like muscle)
Prevent weight gain after weight loss
You can get protein from food sources like meat, fish, tofu, nuts, and dairy products, along with supplements like protein powders, shakes, and bars.
Protein supplements might also help you reduce your portion sizes. A small 2011 study found that consuming 20 grams of casein (a milk protein) or pea protein before a meal led to eating less at that meal. This was compared to drinking water before a meal.
Casein and pea protein were more effective than whey protein at increasing satiety — the feeling of fullness.
Pros:
Protein may help you build or retain muscle mass and keep off any weight you’ve lost.
If you’re a vegetarian, vegan, or otherwise don’t get enough protein from your diet, protein supplements can help you get enough of the nutrient.
Cons:
More research is needed on protein supplements for weight loss specifically.
Best for: People who can’t get enough protein from food sources, those looking to preserve or build muscle, or those interested in weight management.
Final verdict: Eating more than the daily recommended amount of protein is linked to weight loss, decreased fat mass, retaining muscle, and keeping off lost weight. More studies on protein supplements are needed.
If you want to understand the role protein plays more clearly, our guide on whether protein is good for weight loss explains how it supports appetite control, metabolism, and fat loss.
5. Fibre
You’ll find fibre in fresh fruit, vegetables, legumes, whole grains, and in supplement form, and it may help with weight loss.
Soluble fibre has been linked to:
Increased satiety
Better cholesterol levels
Improved glycemic response (how your body regulates blood sugar after eating)
Weight loss
A 2017 systematic review and meta-analysis looked into 12 randomised controlled trials with upwards of 600 people with overweight or obesity. Participants supplemented with soluble fibre for two to 17 weeks.
Compared to a placebo, soluble fibre supplementation led to an average reduction in:
BMI by 0.84 units
Body fat by 0.41 percent
Body weight by 2.52 kilograms
Beyond weight metrics, soluble fibre supplements also reduced fasting blood sugar levels and insulin levels.
But before you add fibre supplements to your shopping list, more research is needed to confirm. Although promising, the studies in this review were very different, so it’s hard to compare the results and draw any firm conclusions.
Pros:
It can be difficult to get enough fibre from food sources, so supplements can help.
Fibre supplements may be beneficial for weight loss and managing blood sugar and insulin levels.
Cons:
Fibre from food sources can help you feel fuller, but more research is needed to know if supplements have the same effect.
Best for: Those who can’t get enough fibre from food sources.
Final verdict: Soluble fibre supplementation may lead to weight loss and a reduced BMI and body fat, but more research is needed.
What Vitamins Help With Weight Loss?
Maybe you’re already taking a multivitamin or vitamin D during the winter. But one vitamin in particular has potential as a weight loss vitamin: vitamin B12.
Here’s why.
6. Vitamin B12
Those with overweight or obesity are at risk for vitamin B12 deficiency. A 2013 study looked at almost 1,000 participants with overweight, obesity, or a “healthy weight.”
Vitamin B12 was significantly lower in those with overweight and obesity compared to those with a healthy weight. Vitamin B12 was also negatively associated with BMI. The lower the vitamin B12, the higher the BMI.
Beyond obesity, you may be more at risk for vitamin B12 deficiency if you:
Eat a vegetarian or vegan diet. Vitamin B12 is found in foods like meat, fish, and dairy.
Take metformin. Metformin is a medicine for type 2 diabetes and polycystic ovary syndrome (PCOS). It may cause vitamin B12 deficiency.
If higher levels of vitamin B12 have been linked to a lower risk of overweight, could supplements help?
A 2019 study tried to answer that question. It included almost 3,000 people who took folic acid (vitamin B9) and vitamin B12 or a placebo for two years.
Higher vitamin B9 levels were linked to a lower BMI, but there were no significant changes to BMI, fat mass index (fat mass relative to height), or fat-free mass index (fat-free mass relative to height) from taking vitamin B9 and B12.
However, vitamin B12 supplements could still support your weight loss treatment plan.
Vitamin B12 deficiency can lead to fatigue. And fatigue can make weight loss efforts like sticking to a healthy eating plan or doing more physical activity much harder.
Pros:
Vitamin B12 deficiency is common, especially among those with overweight or obesity and people taking metformin.
If you’re deficient, a vitamin B12 supplement might boost your energy levels, helping you stick to your weight loss plan and feel better in general.
Cons:
Vitamin B12 supplements might be better for people with metabolic syndrome or those who have a deficiency.
More research is needed to know if B12 vitamins for weight loss are useful.
Best for: Potentially everyone, but especially people who can’t get enough vitamin B12 from their diet, those with a deficiency, or folks with metabolic syndrome.
Final verdict: If you have overweight or obesity or take metformin, you could have a vitamin B12 deficiency. More research is needed to know if vitamin B12 can aid weight loss.
Unlock your treatment plan
What to Look For in Weight Loss Supplements
If you’re searching for weight loss products, you likely have questions. How do you know which supplement is worth the money? How do you know a supplement will actually work? Which claims can you believe?
This handy buying guide will help you assess weight loss supplements.
Red Flags:
Claims that seem too good to be true. Watch out for phrases like “miraculous cure,” “scientific breakthrough,” “ancient remedy,” or “secret ingredient.” Anything that says it can end cravings, burn belly fat, or get results fast should also make you sceptical.
Non-prescription diet pills. You’ll probably notice the above phrases on products like these. Non-prescription supplements aren’t always regulated by the MHRA and may not be safe or effective. Watch out for similar products like carb blockers, metabolism boosters, fat loss supplements, or postpartum weight loss supplements (seek medical advice on the last one).
Fat burners. Any product with this kind of phrase is a big red flag. These products say they increase fat metabolism or energy expenditure and reduce fat absorption. But a 2021 study says otherwise — it found that they’re not all that effective.
Low prices or money-back guarantees. If you see a too-good-to-be-true deal, it might be too good to be true. Watch out for products promising no-risk trials or money-back guarantees.
Green Flags:
Reputable brands. Look for brands you know and trust that have a history of creating safe and effective supplements. Check out the company’s website and socials. Look for third-party testing and certification badges from official testing organisations.
Clear ingredients. Check ingredient lists and look out for any ingredients we’ve mentioned above. If a product doesn’t list its ingredients plainly, that could be a warning sign.
Good reviews. When scanning reviews, look for stories of safe, steady, sustainable weight loss.
That’s a lot of potential flags. Choosing a weight loss supplement can feel like a scary and impossible task, but speaking with your GP (general practitioner), a chemist, or a dietitian can help you make the right decision.
A medical professional can assess the safety of any supplements you’re considering, taking into account your personal circumstances and any health conditions you may have or medicine you’re taking.
You can also talk to your GP or a dietitian to find out if you have any nutritional deficiencies and whether supplements like calcium, iron, or probiotics would be beneficial.
Finally, a professional can recommend other treatments that may be more effective for weight loss, as well as lifestyle changes you can make.
Are Weight Loss Supplements Safe?
Weight loss supplements in the U.K. aren’t always regulated by the MHRA. The majority of supplements are covered by food law, but they only need to follow medicinal regulation if they have a medicinal effect or make a medicinal claim.
That means many haven’t been assessed by the MHRA and approved as safe for certain uses.
Our advice? Consult your GP or a care provider before taking any new supplements to make sure they won’t be harmful to your overall health and wellness.
How Effective Are Weight Loss Supplements?
Weight loss supplements may not be as effective as they claim. It depends on what kind of supplement you’re taking, though.
In general, there’s limited high-quality research proving weight loss supplements work.
Studies looking into specific supplements — like green tea extract, magnesium, and fibre — show promising results. But more data is needed, especially to find out the best weight loss supplements overall.
The best supplements for weight loss may depend on your unique circumstances, like your eating habits or whether you have a nutritional deficiency.
If your progress feels slower than expected, exploring why you might not be losing weight can help you understand common factors that may stall results.
Weight Loss Supplement Alternatives
Natural weight loss supplements are unlikely to be the magic weight loss pills some claim them to be. But there are other treatments with more scientific backing.
The following medicines are sometimes used to support weight loss:
Mounjaro® (active ingredient tirzepatide)
Wegovy® (semaglutide)
Saxenda® (liraglutide)
Orlos®, Alli®, or Xenical® (orlistat)
Weight loss medication is rarely available through the National Health Service (NHS) due to strict eligibility criteria and supply constraints. However, if eligible, you can access these medications privately through a private GP, online pharmacy, or online weight loss programme.
Your GP or a private provider can help you determine if weight loss medicines are suitable for you.
Besides medication, healthy lifestyle changes — like eating a balanced diet with fewer calories, moving your body more, and getting enough sleep — can help you reach your weight loss goals.
If you prefer to focus on movement alongside supplements, our weight loss gym routine for women offers a simple structure to help you build strength and support fat loss.
Your plan is waiting
Best Weight Loss Supplements: Your Next Steps
Garcinia cambogia, glucomannan, chromium, carnitine, conjugated linoleic acid (CLA). Yes, we’re still speaking English. These are all supplements.
Take one peek in a chemist’s or health food shop, and you’ll see there’s no shortage of weight loss supplements available for purchase. But just because they’re on the shelves doesn’t mean they’re safe or effective.
Here’s what you need to know about the best weight loss supplements:
Supplements aren’t always regulated by the MHRA. There’s no guarantee of effectiveness for weight loss.
There are a few promising weight loss supplements. Some supplements have potential. Magnesium, fibre, protein, and vitamin B12 may support your overall health and weight loss efforts.
Get medical advice before taking a new supplement. Before taking a new supplement, get advice from your GP or a healthcare professional. They can tell if it’s safe and recommend other treatments that may work better.
Weight loss supplements, even when safe and effective, are just one piece of the puzzle. A holistic approach — combining a balanced diet, movement, and personalised expert advice — is best.
If you’re wondering what realistic progress looks like, our guide on how long it takes to lose weight explains typical timelines and the factors that can speed up or slow down results.
For some, prescription weight loss medicine is another tool that can help. Take our online weight loss assessment to find out if medicinal weight loss is right for you.
This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your GP about the risks and benefits of any treatment.