The word supplement is defined as “something that completes or enhances something else when added to it.” In this case, the “else” is your diet, and the “something” is a wide variety of supplements, from 5-HTP (Dr. Oz’s latest favorite supplement) all the way to zinc.

This guide will help you understand how and where your diet breaks down, and how you can use supplements to fill in those gaps, resulting in a healthier you.

Macronutrient Supplementation

Your diet is based around macronutrients – nutrients that give you calories. The three main sources of calories are fatty acids (fats), carbohydrates (carbs), and dietary proteins (proteins); alcohol is sometimes considered a fourth macronutrient as it also has calories.

Ideally, your macronutrients and calorie goals should be determined ahead of time and these should be something you target for each day. For example, targeting 1 gram of protein per pound of body weight (so for a 150lb person, 150 grams of protein).

Food is the best choice to get macronutrients from, but supplements are a useful aid in areas you fall short. None of these supplements are mandatory, but they can help make your overall diet more manageable and enjoyable, especially if getting the nutrition you need from food is difficult or expensive.

Dietary Protein (Protein)

Dietary protein is fairly universal. The greatest sources are meats and alternatives such as eggs, with a good amount of protein being derived from dairy products (milk, cottage cheese, greek yogurt, etc).

Protein tends to be the most commonly set macronutrient “target,” and protein supplements are commonly used to make meeting protein requirements easier. In places where a steak or chicken cannot be prepared a protein bar or shake can substitute.

The most common supplement of protein is whey protein (the water soluble component of dairy protein) with other options being casein (water insoluble component of dairy), egg, rice, pea, hemp, beef, and soy. For the most part these protein sources are equal to each other. The main factors in buying a protein powder would be price, taste, and how likely you are to use this product.

There is definitely some science behind whey being a better protein source than others for building muscle because of its absorption speed, but that only applies if you are working out without having had any protein beforehand. In practical terms, it is no better than other protein sources.

Fatty Acids (Fats)

Fatty acids are critical to life, with a minor amount of omega-3 and omega-6 fatty acids being required for survival. Fats are required by your body hormones, and other than omega-3s, you should be getting enough via food.

That being said, there are health benefits with having a healthy omega-3 to omega-6 ratio (somewhere between a 1:2 and 2:1 ratio, with 1:1 being commonly stated merely for simplicity). Due to the overabundance of omega-6 in the standard diet, omega-3 supplementation has become popular in an attempt to balance out ratio. Fish oil is the most commonly supplemented fatty acid for these reasons.

A small dose of fish oil (300mg combined EPA and DHA) may be prudent for people who do not frequently consume fatty fish (for example, salmon). If your diet routinely has fatty fish in it, supplementation is likely not needed.

Flax seed is another popular option, but our bodies have a hard time utilizing the form of omega-3s found in flax. A better option for vegetarians would be algae.

Dietary Carbohydrate (Carbs)

For the most part, carbohydrates are rarely supplemented. This is because most carbohydrate supplements are not different than candy, and we can all agree that candy is much more delicious. There are definitely some supplements targeted towards people who lift heavy weights (glucose or other ‘post workout’ supplements), but these are not significantly better from using food sources.

Micronutrient Supplementation

Multivitamins are a very common supplement, usually with a ‘better safe than sorry” approach and the hope that a single pill can be enough to avoid possible nutrient deficiencies. Unfortunately, multivitamins are quite useless in most scenarios.

The major problem with multivitamins is their formulation. Pills can only physically fit so many molecules, and many companies are hesitant to make a multivitamin require more than one or two pills a day. Due to this, most multivitamins are under-dosed.

As quick examples, magnesium and calcium, two minerals required in excess of 400mg daily, are almost never in quantities close to the RDA in multivitamins.

Because multivitamins’ shotgun approach is so weak, it is better to just buy the supplements for nutrients you are likely deficient in. Price is slightly cheaper, and the dose is definitely higher; the only downside is more pills.

What are Really Common Deficiencies?

Two very common deficiencies are vitamin d and magnesium.

Vitamin D tends to be commonly deficient due to two reasons: 1) the RDA used to be only 400 IU (which was just enough to prevent rickets) and 2) pollution/more time indoors/more covered up means less sun exposure. Vitamin d has a lot of healthy benefits as it is involved in a lot of the body’s processes. 1,000-2,000 IU daily appears to be the lowest active dose for health purposes. Food products such as milk may be advertised as “fortified with vitamin d” but they are highly under-dosed.

Magnesium can be acquired via the diet if desired, but it is not easy to do. Good sources of magnesium rarely have even 20% of the RDA, and meeting the RDA each day would require multiple servings of macadamia nuts and leafy green vegetables. Every day.

So although it is possible to get enough magnesium via food, it’s quite difficult. Thus, deficiency rates appear to be quite high in society.

What if I’m Really Athletic?

Zinc is a dietary mineral which is quite rare to be deficient in a sedentary population, whereas deficiencies appear to be higher in people who sweat a lot (usually this is athletes). Zinc is lost through sweat, and so supplemental zinc is commonly used for athletes to replace the lost zinc.

There is a combination supplement known as ZMA which contains both zinc and magnesium. ZMA tends to be hyped up for the purposes of boosting testosterone (don’t put too much faith into it) but might be a cheap and convenient way of simply getting both zinc and magnesium. Lots of people claim that ZMA also helps them sleep better.

Do females have any particular requirements?

Possibly. Iron and calcium deficiency rates are much higher in females. Both of these are more related to diet, but the higher rate of deficiency is well established.

It is possible that you can get iron supplementation from a medical doctor and a nice supervision of blood iron concentration if you are anemic or very deficient. A medical consult is recommended since excessive iron has adverse effects.

Calcium supplementation might not be needed if you are taking whey or casein protein (as they tend to give you 20% and 60% of the RDA of calcium per scoop, respectively). Otherwise, supplementation should be investigated.

Supplements That Increase Physical Performance

Power Output

Power output surprisingly has little substantial and proven evidence behind its claims, although two supplements stand out well above others: caffeine and creatine. Both of these can increase your ability to exert power and would be wise choices to increase power output.

Stimulants in general (of which caffeine is one) can increase power output and due to this the power increasing effect may also be extended to other stimulants.

Carbohydrates get a special mention here, as preworkout carbohydrates can easily boost power output during the subsequent workout; a supplement is not necessarily needed here, as a sports drink, candy, fruit, or some cereal would work splendidly.

Muscular Endurance

Muscular endurance supplements tend to be directed to either reducing the speed at which your muscle fails, or helping “clean up” while your muscles are contracting.

The most popular option here appears to be beta-alanine, which is proven effective for exercises lasting more than 60 seconds. Although not a big difference, it is effective and reliable. There is even potentially some benefit for power output.

Beta-alanine works via buffering acidity in muscle tissues, and is something that also happens with sodium bicarbonate (baking soda!) Moderate dosing of baking soda, to avoid intestinal distress, appears to be similar to beta-alanine by increasing muscular performance.

Nitric oxide (a signalling molecule most well known for reducing blood pressure) also appears to be an avenue that is frequently manipulated. Although l-arginine appears effective, high doses can cause diarrhea as it is not well absorbed; l-citrulline is a superior option as it is better absorbed and unlikely to have the explosive side-effects. Both are proven for muscular endurance and power output in anaerobic cardio exercise (so unlikely they will be of benefit to powerlifting).

Supplements That Burn Fat?

Fat burning compounds do exist, but we need to clarify your expectations. They are not very effective, and the ones that are most effective (relative to others) are either potent stimulants with side-effects or simply encourage you to eat less (via appetite suppression – usually nausea).

In the grand scheme of calories in versus calories out, fat burners make a 5% difference; it’s your diet that will be the real reason for any fat loss. We are talking about 100-200 kcal (or even less) daily, which is equivalent to a few oreos. That being said, assuming your entire diet is looking good, this 100-200 kcal addition can slowly add up over time and provide some benefit.

Caffeine and green tea are two ‘fat burners’ that do have evidence behind them, but are limited in their practicality. Caffeine is a great fat burner until you become tolerant to it and lose the stimulatory effects. Green tea catechins (the fat burning components in green tea) are quite unreliable in burning fat and appear to be heavily reliant on a gene product (COMT) that varies widely between races, with some studies suggesting that green tea only promotes fat loss reliably in people of Asian descent. If you are able to drink room temperature green tea and noticeably feel warmer, green tea supplements may work for you. If not, do not waste your money (room temperature tea is important as drinking any hot beverage can give a false positive in this test).

What About Testosterone Boosting Agents?

Testosterone boosting compounds are an interesting group. There are a few compounds that have been shown to work in humans and many that have been shown to work in rats. Despite this proof, it doesn’t mean that much in practical terms since society has conditioned buyers to expect steroid-like gains.

No herbal testosterone booster currently has enough evidence to support their grandiose claims; the testosterone boost is present, and technically it should help with muscle protein synthesis in a dose-dependent manner.

This increase in muscle growth is likely to be barely noticeable, and the most significant benefit one can expect from a testosterone booster is an increase in libido (this applies to both genders). Muscle recovery rates may also be enhanced, but again this is likely to be to a very small degree.

Do they work? Sure. But it’s the equivalent of taking a car’s range from 40 mpg to 42mpg – it was boosted, but not really noticeably.

Common Supplements and What They Do

A few common supplements are to be addressed here, as they can be found in supplements stores or are very commonly added to supplement blends.

Glucosamine

Glucosamine is the most common joint health supplement in the western world, and for no real good reason. It appears to have been one of the first on the market and due to societal exposure it got a lot of research for it; this bounty of research gives the illusion that it is amazingly effective.

It appears to have limited use and benefit for the purpose of reducing the rate of osteoarthritis progression. That’s it. It is just as effective as acetominophen (for osteoarthritis) but acetominophen appears to be preferred due to having more evidence and reliability.

Similar to the testosterone booster analogy of the car’s efficiency, it’s slightly effective. It’s questionable if it’s worth the cost.

Glutamine

Glutamine is an essential amino acid that is involved in muscle protein synthesis; when incubated with muscle cells in a petri-dish, it causes muscle growth.

Sounds great? Except this growth does not happen in our bodies. Supply of glutamine to muscle cells is tightly regulated, thus making it useless as a muscle builder.

It appears to be anti-catabolic (preventing muscle loss) in periods of severe physical trauma such as tissue injury or burn victims.

The muscle growth promoting effects of glutamine supplementation are greatly overhyped, and they are currently not supported by evidence. Glutamine, as of right now, appears to be beneficial for gut health (although this benefit also exists with high dietary sources of glutamine, such as whey or casein protein). If you eat enough protein, glutamine has absolutely no benefits.

BCAAs – Branched Chain Amino Acids (as well as Leucine and HMB)

Branched chain amino acids (BCAAs) are three amino acids characterized by their branched side chains: leucine, isoleucine, and valine. They are muscle-saving, and when taken if you’ve been fasting they do appear effective at this claim. These effects are mostly related to the amino acid leucine, and are somewhat mimicked by HMB (ß-hydroxy-ß-methylbutyrate).

The practical significance of BCAA supplementation is limited – BCAAs are found in regular protein (and at high levels in animal products and some grains). Although BCAAs per se are important for muscle protein synthesis, a protein rich diet should net you enough BCAAs to not need supplementation.

Arginine (and Citrulline)

Arginine is an amino acid that is able to produce nitric oxide in the body, and nitric oxide appears to be a critical regulating agent for cardiovascular health, blood pressure, and a fairly good regulator of muscle protein synthesis. L-Arginine is supplemented in the hopes of increasing nitric oxide production in the body.

L-Arginine does appear effective at this claim, although to a limited degree as higher doses are not well absorbed and excessive doses cause diarrhea. L-Citrulline seems to be a better option due to it being better absorbed.

Studies on L-Arginine and L-Citrulline do suggest benefit with supplementation, but are not magical by any means. They may also increase anaerobic muscle performance (just like beta-alanine and sodium bicarbonate).

Green Coffee extract and Raspberry Ketones

These two supplements are newcomers to the supplement field and have become popular due to Dr. Oz. As they are relatively new, the research on them is sparse.

Raspberry ketones might be able to act as a thermogenic agent (make you heat up, thus causing more fat to be burned), but this is no scientific evidence of this. For the time being, it is completely unproven

Green coffee extract (GCE) is a source of the molecule known as chlorogenic acid, which is a fairly healthy molecule. It is marketed as a fat burning agent with little evidence to support it. It appears to work via inhibiting carbohydrate absorption in the intestines, but the human studies currently are quite mixed in how effective it really is.

Furthermore, inhibiting carbohydrate absorption is not necessarily a good intervention (literally useless on a ketogenic diet and limited use for a low carb and calorie controlled diet) and is not unique; many agents from plants can inhibit carbohydrate uptake.

Soy isoflavones

Soy isoflavones is a term used to refer to two main molecules, known as genistein and daidzein. These isoflavones are said to be estrogenic and reduce symptoms of menopause.

They are indeed estrogenic, but are fairly weak at doing so. Due to the inherent weakness of these molecules on the receptor, they tend to induce small estrogenic effects in people without much circulating estrogen (menopause) and do not have this effect or many even be anti-estrogenic in people with higher estrogen levels (any one not going through menopause). Similar to glucosamine, they are technically effective but the magnitude of effect is fairly small. Worrying about soy is a waste of time

Wrap Up

This guide is definitely simplified, but it should get the major points across. Your focus should always be first on your diet, and then figuring out where there are holes in your diet, and then potentially filling in those holes via supplements.