Health Nutrition Slimming

Supplements For Weight Loss That Work (And Those That Don’t)

Many vitamins and supplements claim to aid weight loss and boost metabolism. The truth is, there is very little scientific evidence to support many of these weight loss claims.

Learn what the experts have to say about proven weight loss benefits of these supplements.

Supplements that Aid Weight Loss

Vitamin D for Weight Loss          

Did you know that low vitamin D levels have been associated with insulin resistance and increased levels of chronic inflammation? However, the exact role vitamin D contributes to weight loss has not been determined.

Vitamin D is produced when you are exposed to sunlight and you can also get a reasonable amount from fatty fish such as tuna, salmon and mackerel.

A study published in 2014 placed 218 women on a calorie controlled diet with vigorous aerobic activity. Those who achieved healthy level of vitamin D during the study showed that taking the supplement did not aid weight loss. Additionally, those that became ‘replete’ i.e. their vitamin levels in their body rose to a healthy level did lose more weight.

Correspondingly, a study also published in the American Journal of Clinical Nutrition found that overweight and obese adults taking calcium and vitamin D lost considerably more stomach fat than those who weren’t.

man and daughter walking on beach
Exposure to sunlight produces vitamin D

Magnesium for Weight Loss 

Magnesium is a vital nutrient responsible for over 300 biochemical reactions in the body. It is necessary to support the chemical reactions that produces energy.

Additionally, it regulates blood sugar levels and helps your body manage nerve impulses, muscle contractions, blood pressure and regulates normal heart rhythm. Magnesium is also important for balancing many hormones associated with your mood. Many studies have linked magnesium deficiency to an increased risk of depression and anxiety.

In fact, a 2003 study of 219 women by Simmons College found that those with higher magnesium intakes had lower fasting insulin levels. Essentially, they were more sensitive to the insulin in their bodies, resulting in more stable blood sugar levels.

A later study of 234 people in China, in 2013 established that ‘increasing dietary magnesium to meet the RDA has a protective effect on insulin resistance’.

A 2013 study found that taking higher amounts of magnesium helps better control insulin and glucose blood levels. This same study also showed magnesium helps with bloating and water retention.

Fibre for Weight Loss 

Fibre has been proven to aid weight loss. It helps fill you up and helps you feel fuller for longer, which reduces cravings. It also helps normalise you blood sugar, so you don’t get those 11am and 4pm energy slumps.

A number of studies from the national library of medicine have been published since the invention F-plan in the 80’s analysing the effect of fibre on weight loss. In 2009 a study indicated that a person could reduce calorie intake by 10% by eating only 14 grams more fibre per day.

bowl of muesli
Fibre helps keep a healthy gut and aids weight loss

Probiotics for Weight Loss 

Probiotics have grown in popularity, as they offer a wide variety of health benefits.

These benefits include managing your weight, boosting your immune system, and keeping your digestive system healthy. Probiotics are essentially good bacteria, which is usually found naturally in your body. However, poor diet, stress, chemical additives such as sweeteners and some medicines can affect our natural flora. This can result in an overload of bad bacteria in out gut. To that end, the imbalance in bacteria can result in weight loss difficulty and other conditions such as thrush or urine infections.  

Research in The British Journal of Nutrition noted the effects that one type of probiotic, Lactobacillus rhamnosus, had on people with obesity. When compared to those taking a placebo, the women who took the probiotic supplement lost more weight during the study. Furthermore, they continued to lose more weight after they finished dieting.

Another 2013 study looked at the effects of Lactobacillus ermentum and Lactobacillus amylovorus. At the end of the 6 week study the participants had lost an average of 3–4% body fat.

Spirulina for Weight Loss 

Spirulina is a type of algae. It is considered a superfood as it contains exceptional nutritional content and it offers a number of health benefits .

On account of its high protein and vitamin content, it an excellent dietary supplement for people on vegetarian or vegan diets.

Research suggests that spirulina has antioxidant and inflammation-fighting properties, as well as the ability to help regulate the immune system.

A clinical trial in 2016 indicated that spirulina can aid weight management. In the trial, participants who regularly consumed spirulina for 3 months showed improved body mass index.

Another study in 2020 noted it’s positive impact on weight loss and blood lipids (the fatty substances found in the blood) It improved in insulin sensitivity and satiety (the feeling of being full).

Fat for Weight Loss 

Ok, so this is not a supplement. Nevertheless, I want to raise the importance of fat in losing weight. Fat has been demonised by many mainstream diets, but fat is essential for the healthy functioning of your body. Your natural biological processes need fat to function. Dietary fat supplies essential fatty acids for growth, healthy skin, vitamin absorption, and for the regulation of bodily functions. Healthy fats come from fish, meat and vegetables.

So, if you have been focused on cutting calories to lose weight, you may think that it’s a good idea to reduce high-fat ingredients, like nuts or avocados. Fat does contain calories per gram than carbohydrates or protein. But that is the problem with calorie-controlled diets, you’re missing the bigger picture.

Fat keep us satiated, i.e. they make us feel less hungry. Fats take longer to digest than carbohydrates and leaves us feeling full for longer. Additionally, smaller portions of food are more satisfying when they contain fat. After eating a balanced meal with some natural fats, you are less likely to snack between meals.

Avocados have many health benefits and high in healthy fats

Supplements That Do Not Aid Weight Loss

So, when I say these don’t aid weight loss, I’m saying that there is no supportable scientific evidence that it works to boost metabolism or help weight loss. However, a number of supplements will help improve your biological functions, improve immunity and benefits you as a whole. So there are health benefits which may help you become more energetic, feel happier and then indirectly assist a lifestyle change.


Iron helps your body create energy from the nutrients in the food you eat. It also helps create red blood cells which carry oxygen to your muscles. If you do not have enough iron in your system, you could develop anaemia. This results in fatigue, weakness and low energy levels. What do you do when you are tired? Yep, you eat high sugar, calorie dense foods that you think will give you energy. In other words, whilst iron may not directly help you lose weight, it is essential to keep you energetic and healthy.

B Vitamins

The B vitamins include:

  • thiamine (B-1)
  • riboflavin (B-2)
  • niacin (B-3)
  • pantothenic acid (B-5)
  • pyridoxine (B-6)
  • biotin (B-7)
  • folate (B-9)
  • cobalamin (B-12)

B vitamins are necessary to support your metabolism. They help process the stored energy in food into energy that you use.

Ironically, I found it difficult to find clinical trials analysing the effect of just B vitamins on weight loss. There is little evidence supporting Vitamin B’s contribution for weight loss. There are a number of studies with a vitamin complex. In addition, analysing the impact of B vitamins on overweight rats. A small study in 2019 of 33 overweight patients  identified that the group that ate vitamin B enriched yoghurts reduced their body weight and BMI to a greater degree than the group that followed the same diet without the yoghurt.

Green Tea Extract

I am a big fan of eating a whole food, balanced diet. Although, I know it is important to provide an objective view. To that end, there is evidence that green tea extract ‘could’ potentially benefit weight loss. Green tea extract contains catechins and caffeine. Caffeine is known for elevating heart rate and making people feel more energetic.

Picture of green tea powder and tea
Green tea has not been proven to benefit weight loss

In 2012 a study looked at weight loss and weight maintenance. Green tea preparations appear to induce a small, statistically non-significant weight loss in overweight or obese adults. Because the amount of weight loss is small, it is not likely to be clinically important.

However, most studies have proven non conclusive results.

Chromium Picolinate

Chromium is a mineral that enhances insulin, a hormone used for turning food into energy. Unsurprisingly, there are suggestions that chromium supplements can lower your appetite and aid in the burning of calories

However, a review in 2019 looked at 9 studies involving 622 participants. They found no current, reliable evidence to inform firm decisions about the efficacy and safety of chromium supplements in overweight or obese adults.

There have also been questions about its safety and carcinogenic effects.

Bitter Orange (Synephrine)

Bitter orange is also know as the Seville orange (yep the one you find in marmalade!) There are claims that bitter orange can help you lose weight.

Picture of oranges
Bitter orange comes from the Seville orange

The Irish times reported a small number of clinical trials have studied bitter orange as a weight-loss supplement. However, none of them studied bitter orange on its own. All of the supplements contained caffeine along with various other herbs like St John’s wort, ginseng or Gingko. Most of the studies also included an exercise programme.

Only two of the studies found greater weight loss with the supplement than placebo. Over the course of the studies, those taking one of the supplements lost an average of 2-3kg. While those in the placebo groups lost an average of 1-2kg. However, it is not possible to determine how much bitter orange contributed to the weight loss.

On account of the potentially serious health problems you should be wary of taking bitter orange. The compound synephrine in bitter orange may speed up your heart rate and increase blood pressure. This rise can cause headaches, trigger migraines, fainting and is sometimes associated with heart attacks. Bitter orange can also have bad reactions with over the counter and prescription medications.

Raspberry Ketones

A popular health claim is that raspberry ketones can cause weight loss. However, as hard as I tried, I could not find any scientific evidence supporting this claim. Any evidence I could find was extremely weak. Albeit there is evidence, all of it is based on animal testing.

Medical news today state “No clinical trials on humans have found that raspberry ketones can cause weight loss.”

So, if you are a rat, you are in luck. If like me, you are a human then you may choose to stick with healthy eating as safer option.


What we can infer is that supplements alone do not necessarily work. Vitamins and mineral are tricky to manage. So that your body to process and absorb them they often need a mix of other vitamins and minerals. Essentially, if you are eating junk food on a regular basis but taking a supplement, you are unlikely to reap any health benefits. However, as part of a lifestyle change, they can aid weight loss.

Writing this blog involved me researching hundreds of sources. Notably, the majority of sources claiming benefits did not have any scientific supporting evidence. Take time to decide what you want to put in your body by researching the evidence behind any false health claims.

From my research, there is no pill or potion that will help you lose weight. Now, we all know eating a well balanced diet is the key to success. So it is important to remember supplement is just that – supplementary i.e. in addition to. However, a good vitamin and mineral supplements can help your biological processes which will provide you with more energy, help manage stress, improve your mood. All of these factors combined will contribute to a more successful lifestyle change.

Read more about creating a healthy life and mindset for you and your family here

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