Are supplements the best way to replenish electrolytes?

Dinner plate covered in supplement pills with two forks

Key points

Supplementing with sodium is safe, but not necessary unless you’re on keto or very physically active
Avoid potassium supplements unless prescribed or you cannot get enough from food
If you do take potassium supplements:
- Use potassium citrate, not chloride or bicarbonate
- Take together with food, and keep within 99mg per dose
Magnesium supplements are safe to take, but watch the dose to avoid laxative effects
The best magnesium supplements to take are:
- Magnesium citrate – best for muscle relaxation
- Magnesium L-threonate – best for brain function
- Magnesium orotate – best for energy production and avoiding laxative effects
Avoid calcium supplements unless prescribed by your doctor
If you do take calcium supplements, make sure to take Vitamin D too!

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Why not take a multivitamin and call it a day?

Taking a pill has become a cultural phenomenon. Take pills to reduce pain, pills to help our sleep and pills to get all our nutrients. However, is taking a supplement always the best way to replenish electrolytes? How is it different from getting them from food? Does how you take the supplement (i.e. on an empty stomach or not) matter? Did you know that not all magnesium supplements are the same?

Just as there’s good quality food, there are good quality supplements. Just because a supplement contains some substance, that doesn’t mean it’s the best way to get it into your body. This study found that people with high calcium intake primarily from food had decreased risk of heart disease, but those who used calcium supplements sometimes had increased risk of heart disease. Likewise, potassium supplements such as salt substitutes can cause anxiety, irregular heartbeat, and even cardiac arrest.

Another issue is balance. As we’ve covered in our previous article here, electrolytes interact closely with each other and need to be in balance – sodium in balance with potassium, magnesium in balance with calcium, zinc in balance with copper, and so on. It’s not enough just to take a lot of them, and in some cases it may not be safe to do so. While the body works hard to correct imbalances, symptoms can occur that affect our health, cognition and performance. While there are many factors involved, the simple point remains that taking an electrolyte supplement is not necessarily the best way to go. Let’s take a closer look.

Which electrolytes should you supplement? Which should you not?

Food is almost always going to be the better choice for getting your nutrients. Try and get all the nutrients you possibly can from your food in the context of a healthy diet (that is, unless your doctor or a health professional gives you a specific recommendation or prescription). However, there are times when we can’t get easy access to complete, wholesome food – perhaps because we’re busy, or travelling. Let’s review the specifics so you can supplement where necessary in a safe, effective way.

Sodium: Safe to supplement, but only needed for keto or intense exercise

Generally speaking, it’s enough to simply salt your food to taste – no supplements required. There are a few reasons for this. Firstly, most people already consume salt in excess of the recommended dietary intake. Secondly, many people don’t consume enough potassium and magnesium, so in general we should focus on increasing intake of these rather than salt.

However, you may want to supplement with extra salt if you’re doing something that has you sweating for a long time – like a marathon or hours of hard work in the heat. Research indicates that you should ingest around 450mg of sodium (around 1/6 of a teaspoon of salt) per hour during athletic events. If you’re an endurance athlete, you might want to look into buying some salt pills or salt tablets. Electrolyte drinks can be helpful, but if you’re not dehydrated then the additional fluids could actually dilute your blood electrolyte concentration.

Another situation in which you may want to take extra salt is when on the keto diet. Because your carbohydrate intake is very low on keto, your body secretes less of the hormone insulin. One of the effects of insulin is to cause your body to retain sodium, and with it water. It’s common for people to experience so-called “keto flu” symptoms in the early stages of ketosis, which are thought to be partly the result of sodium and water loss. While you may also need to supplement potassium and magnesium during keto, this is not due to reduced insulin secretion, but likely due to (i) disruptions in electrolyte balance caused by a drastic loss of sodium, followed by increased excretion of potassium and magnesium to maintain balance; and/or (ii) a lack of these electrolytes in your diet due to restricted intake of fruit and vegetables.

Lastly, if you’re worried about your salt or sodium intake, take a look at our article here to see why reducing it might not be a good idea.

Potassium: Focus on food, only take supplements where prescribed

You should aim to get all your potassium from food, but if you have trouble with that and you need to supplement, here are some things to remember. There are three main forms of potassium supplement:

Potassium citrate
Potassium chloride
Potassium bicarbonate

According to nutrition expert Chris Masterjohn, PhD, potassium citrate is the best form of potassium supplement to take, and should be consumed together with food to mimic normal ingestion. You can achieve this by buying a potassium citrate powder and mixing it into a meal, or taking a capsule at the same time. Check the serving size carefully – the FDA carefully regulates potassium supplements to make sure that they don’t exceed 99mg per dose. The reason is that the potassium in supplements is absorbed into the blood faster than food, and so can potentially cause a condition called hyperkalemia, which is particularly dangerous if you have kidney issues.

Potassium chloride is commonly found in salt substitutes. It’s probably best to avoid potassium chloride, because it can irritate the stomach lining – in one study, a person was found to have ulceration in the upper gastrointestinal mucosa after just 7 days of taking potassium chloride supplements. Slow-release potassium chloride supplements in particular should be avoided – ulceration of the small intestine has been found in people taking these, presumably because the tablets remain in the gut and irritate the lining for longer.

Potassium bicarbonate is an antacid – medication used to neutralize gastric acid for a short time. It is commonly used to treat stomach ulcers and acid reflux, but if you don’t have these conditions you don’t need to take it.

Magnesium: Safe to supplement, but avoid magnesium oxide

As for potassium, you should aim to get most of your magnesium from food. However, the difference is that it’s much safer to supplement with magnesium than with potassium. Magnesium supplements come in numerous forms and each have difference properties:

Magnesium citrate
Magnesium L-threonate
Magnesium orotate
Magnesium sulfate
Magnesium taurate
Magnesium malate
Magnesium oxide

Magnesium citrate is one of the most bioavailable forms of magnesium available, i.e. it is most easily absorbed from the digestive tract. It’s good for muscle relaxation and has been found to reduce the incidence of muscle cramps at night. However, it can also have a laxative effect, so unless you have constipation it’s worth checking the dose carefully!

Magnesium L-threonate is a promising form of magnesium developed by a team at MIT, and is the type which is most easily absorbed into the brain. In several studies on animals, the compound was found to boost brain magnesium levels by around 15% and improve brain plasticity and memory function, with suggestions that it might help alleviate symptoms of Alzheimer’s and Parkinson’s Disease.

Magnesium orotate is a form of magnesium that contains orotic acid, a substance used by the body to construct DNA and other genetic material. It’s easily absorbed from the gut but doesn’t have the laxative effects of other forms like magnesium citrate or oxide. Orotic acid has been shown to enhance energy production by supporting synthesis of glycogen and ATP, making magnesium orotate a popular fitness supplement.

Magnesium sulfate (also known as “Epsom Salts”) is a magnesium supplement that is typically not ingested, but instead applied to the skin to soothe sore, achy muscles and relieve stress.

Magnesium taurate is a combination of magnesium and the amino acid taurine. Research suggests that this compound helps maintain healthy blood sugar levels and blood pressure. If you don’t eat dairy, shellfish or meat (all of which are rich in taurine), you may want to consider supplementing with magnesium taurate. Otherwise, you’re probably fine provided you have enough magnesium in your diet.

Magnesium malate is a form of magnesium which like magnesium citrate absorbs well from the digestive tract. It’s sometimes reported to be gentler and having a weaker laxative effect than magnesium citrate or oxide. It’s occasionally recommended as a treatment for symptoms of fibromyalgia and chronic fatigue, but there’s currently no strong evidence to support this.

Magnesium oxide is the form of magnesium which is most poorly absorbed from the gut, and so should generally be avoided. Other forms to avoid are magnesium carbonate, chloride, and gluconate, which together with magnesium oxide are known for causing diarrhea.

Calcium: Avoid supplements unless prescribed by your doctor

As we indicated at the start of this article, as a general rule you should avoid calcium supplements. A number of studies have indicated that high intake of calcium from supplements can increase risk of major cardiovascular events, myocardial infarction, and stroke. You want calcium to be deposited in your bones, not your arteries! One theory is that having all this concentrated calcium introduced to your system at once makes it hard to process and it gets in places it shouldn’t be. This is similar to how a large dose of potassium supplement can cause hyperkalemia by elevating blood levels faster than they would rise with food alone.

However, a few studies contradict that idea and suggest that calcium supplements do not raise heart disease risk. Confused? It seems the decisive factor may be having enough Vitamin D. Vitamin D helps your body absorb calcium and phosphorous from the gut, and bones cannot be formed with calcium alone – phosphorous is needed too. This is likely why studies where calcium and Vitamin D are taken together show no increase in mortality risk. At the same time, there is also evidence that calcium supplementation may increase risk of kidney stones and gastrointestinal problems, so in general you should avoid calcium supplements unless prescribed by your doctor.

The good news is that there is no evidence to suggest that high dietary calcium intake can be harmful. However, there’s just one thing to bear in mind. As we mentioned in our earlier article, (i) calcium is dependent on magnesium for absorption from the gut; (ii) high calcium intake and low magnesium intake impairs absorption of both magnesium and calcium. If you’re going to supplement with calcium, you may want to supplement with magnesium at the same time. And don’t forget the Vitamin D!

In conclusion

The most important takeaway here is to try to get as much of your electrolytes and nutrients from food. Supplements are to be used where:

You can’t get enough from food due to allergies or diet choices
You’re highly physically active
You have a medical condition that requires them

The other key point to remember is – not all supplements are made equal! Pay attention to three things:

Is the form optimal for my health goals?
Does it have any known side effects?
Should I be taking anything else at the same time? (e.g. food, Vitamin D)

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