Low-Carb Diet Tiredness FatigueAre you on a low-carb diet, and feeling tired all the time?

You are not alone. Most people go through a period of fatigue when they start a low-carb diet. It’s a natural side effect of cutting out carbs.

The good news is, it is temporary. And you can improve it.

Here’s how you can fight tiredness with nutritional supplements.

Why do I get tired on a low-carb diet?

Your body can get energy from three sources:

  • carbohydrates in food – source of fuel on a “standard” average diet
  • fat in food – preferred source of fuel once you switch to low-carb
  • fat reserves stored within your body - this is the one we really want to use up!

Your body is used to running on carbs. On a low-carb diet, you replace carbs with fat.

This change forces your body to burn fat for energy – both dietary fat and stored fat.  

The switchover is not immediate. Initially, your body won’t metabolise fat as efficiently as carbs, resulting in less fuel and lower energy levels.

Remember - it is temporary. Once your body completes the transition, you will get all your energy back, and more.

Once your system starts tapping into the stored reserves of fat, your energy levels will soar. Most low-carb dieters report vastly increased energy as one of the diet’s benefits.

How long does low-carb diet fatigue last?

Tiredness is normally temporary. Its duration depends on many factors – for example, what exactly you eat, how much you exercise, and your body composition.

Typically, most people get over their low-carb fatigue within 2-10 days. Take it easy, stick to your diet, and wait for the tiredness to pass.

Supplements to reduce tiredness and fatigue on your low-carb diet

But what if you can’t just wait for tiredness to go away?

Few of us can afford the luxury of relaxing for a week, because we have so much to do. 

This is where nutritional supplements come in. Supplements are a simple and quick solution to this problem.

Here’s a list of nutrients that can reduce your tiredness and fatigue.

Electrolytes: magnesium, potassium and sodium

Electrolytes conduct electrical impulses in the body and are essential for its normal functioning. Drinking lots of water depletes electrolytes.

On a low-carb diet, you will drink more than usual. Fat metabolism requires more hydration, so you will be thirsty.

Drinking lots of water is great. The only potential issue is that your electrolytes might deplete faster. Amongst other symptoms, lack of magnesium and potassium leads to tiredness.


Supplement with 200-500mg a day (50-125% of NRV). Many over-the-counter supplements provide these amounts in a single pill. Magnesium is a relaxant, so it’s best to take it before bedtime.


Supplement with 400-500mg a day (20-25% of NRV). Potassium overdose can be dangerous, so most supplements play it safe with tablets of about 99mg (5% of NTV). You can take 4-5 of those a day safely.

B vitamins

B vitamins are vital for normal energy-yielding metabolism. Higher dosages of B vitamins reduce tiredness.

Some B-vitamins come from high-carb sources like grains and beans, so you might get less of them on a low-carb diet.

To fight fatigue on a low-carb diet, take an extra-strong supplement with a full range of B-vitamins:

  • Vitamin B1 (thiamine)
  • Vitamin B2 (riboflavin)
  • Vitamin B3 (niacin)
  • Vitamin B5 (pantothenic acid)
  • Vitamin B6 (pyridoxine)
  • Vitamin B7 (biotin)
  • Vitamin B9 (folic acid)
  • Vitamin B12

Most B-vitamins have a very high safe upper limit. Extra-strong B-vitamins supplements can contain up to 3000% of RDA.

Vitamin C

Lack of vitamin C can also contribute to tiredness. Best sources of vitamin C are fruit and so high in carbs.

You can safely supplement with 200-300% of NRV.

Low-Carb Diet Multivitamins

Taking a single multivitamin is easier than buying all the required single vitamins separately.

Choose a high-quality, extra-strong multivitamin formula. Make sure it is iron-free and sugar-free. Read more about choosing a multivitamin to support your low-carb diet

We recommend Nutri-Align Multivit - iron-free, sugar-free, extra-strong formulation designed especially for low-carb dieters.

Co-Enzyme Q10

Your body needs co-enzyme Q10 (Co-Q10) to produce energy at cellular level.

Some low-carb diet authors (most notably Dr Atkins) recommend Co-Q10 supplementation to help your body switch to fat-burning metabolism faster.

Supplement with 90g-200g of CoQ10 daily. Oil-based CoQ10 capsules have a better absorption rate than tablets.

Low-carb diet supplements for longer-term tiredness

What if your energy levels don’t improve after several weeks, or don’t respond to the supplements above? This might indicate a deeper problem with your diet.

Start by re-evaluating your diet and macronutrient intake. Make sure that:

  • you are getting enough fat
  • your carb intake is low enough
  • you are counting carbs rather than “guesstimating”
  • you avoid artificial sweeteners

Follow the guidelines of your chosen low-carb diet plan precisely, including any recommendations regarding vitamins and supplements.

Do not try to make your diet stricter than its guidelines – it won’t work. Popular low-carb diets are carefully designed to ensure nutritional balance.

In addition to low-car diet supplements for tiredness we listed above, consider if you are getting enough of the following nutrients. Their deficiency is less common, but possible on a low-carb diet, and could be the cause of your ongoing fatigue.

Iron (if you are vegetarian)

Iron deficiency on a low-carb diet is extremely uncommon. Red meat and green leafy vegetables are the staple foods on a low-carb diet. Both are very rich in iron. So normally iron supplementation is not required, and even discouraged to avoid overdose.

It’s unusual to follow both vegetarian and low-carb diets, but some people do. If this is you, then we would definitely recommend iron supplementation.


Selenium deficiency can affect your thyroid, which in turn can manifest itself as tiredness. Fish and seafood are the best food sources of selenium, as well as beef and lamb. Most low-carb dieters should get enough selenium from food.

If you are vegetarian, or if you get your proteins mostly from poultry and dairy, consider supplementing selenium.

All of the recommendations above are for people who are healthy overall and follow a low-carb diet to lose weight. If you are pregnant, breastfeeding, taking prescription medication or are under medical supervision, consult your doctor before taking any supplements.

All recommendations are guideline only. Please consult your GP, dietician or another registered health professional for individual advice regarding supplementation, to match your actual health and lifestyle profile. Food supplements are not a substitute for a varied and balanced diet.

Low-Carb Diet Supplements to Reduce Tiredness and Fatigue

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