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What is in your protein powder?

If you enjoy pure, unflavored whey protein, then by all means, keep doing your thing. However, companies usually add ingredients to give their product a marketing edge (such as a better flavor), so it’s worth considering if any of these additives should be sought out — or avoided.


Food preservation covers the use of physical and chemical methods to inhibit microbial growth and retain nutritional quality over time, thereby preventing or slowing decomposition. Traditional methods involved manipulating a food’s temperature (boiling, freezing) or physical state (drying, fermentation) or applying natural chemicals (sugar, salt ...). Often, these methods were combined into processes, such as curing (drying, smoking, and salting).

Today, these methods are still used, though often with a modern touch. For instance, pasteurization has replaced boiling, but both involve heating; spray-, freeze-, and vacuum-drying are modern methods of dehydration; and artificial preservatives have superseded sugar and salt. Advances in food technology have also led to novel methods of food preservation, such as irradiation.

Protein powders are preserved through drying, as dehydration (removal of the water content) inhibits microbial growth. It is therefore uncommon for protein powders to contain preservatives, be they natural or artificial. Plus, many preservatives cannot legally be used in protein powders (regulations state not only which preservatives can be used, but in which foods a specific preservative can be used; if a type of food isn’t listed, it is excluded by default). The preservatives you may encounter include notably vitamin C (ascorbic acid or ascorbate), vitamin E (tocopherol), and sorbates (calcium, potassium, or sodium sorbate).

Anticaking agents

Anticaking agents are food additives added to powders to prevent clumping (caking). They work either by absorbing moisture or by coating particles to make them water repellent.

Some common anticaking agents include magnesium stearate, silicon dioxide, calcium silicate, tricalcium phosphate, and stearic acid. You may even see powdered rice used. Most anticaking agents are natural products with well-established metabolic fates (meaning that what happens to them after ingestion is well documented). Magnesium stearate, for example, is simply a combination of magnesium (an essential mineral) and stearic acid (a saturated fatty acid). Calcium silicate is a combination of calcium (an essential mineral) and silica (a trace mineral). At food- additive doses, there is no risk of harm.

A study in some anticaking agents (tricalcium phosphate, calcium silicate, calcium stearate, corn starch, and silicon dioxide) found they hasten the degradation of vitamin C powder in high humidity (>75%),166 but vitamin C is known to degrade in the presence of water, whereas protein powders are not.

Soy lecithin

Because no one likes a clumpy protein shake, many whey protein powders contain lecithin, a natural emulsifier that helps the whey protein dissolve in liquids. Lecithin can be found in every cell in your body. The different types of lecithin are composed of various phospholipids, such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI).

It has been known for decades that dietary lecithin, within the normal diet or as a supplement, gets incorporated in cell membranes and has beneficial health effects on the cardiovascular, nervous, and immune systems. But the amounts in food and supplements are far greater than those found in whey protein powders using lecithin as emulsifier (150–300 milligrams per 30 grams of protein powder, typically: a 0.5–1% concentration).

Lecithin was first identified in egg yolks (and named after them) and has since been found in a variety of foods, with the most common sources today being soybeans and sunflower seeds. Soy lecithin is what you’re most likely to find in whey protein powders, but there is no shortage of articles demonizing it as the worst thing since trans fats simply because it is derived from soybeans.

First, consuming a little soy lecithin as an additive is very different from drinking 3 quarts (2.8 liters) of soy milk per day, as was doing a 60-year-old man when he started suffering from erectile dysfunction, decreased libido, and gynecomastia (an enlargement of breast tissue in men).

Second, most negative perceptions about soy are false, including the idea that regular consumption decreases testosterone and interferes with thyroid function.

Third, soy lecithin oil is nearly 100% fat; it contains very little residual protein and isoflavones (a.k.a. phytoestrogens), the two components that are believed to be implicated in most of soy’s purported negative effects on health. You may have heard that a study “found soy lecithin to be strongly estrogenic”, but its own data hardly support such a strong conclusion. Having found no trace of genistein (soy’s main isoflavone), the authors went to assume that soy lecithin contains “a so-far unidentified estrogen-like compound”. Not only that, but they found estrogenic activity in 3 out of 5 infant formulas — one of the formulas with soy lecithin had no estrogenic activity, and one of the formulas with estrogenic activity had no soy lecithin.

There are also many claims about soy lecithin retaining nasty chemicals supposedly used in its production. Such claims don’t provide credible sources, when they provide any sources at all. As it stands, soy lecithin production is pretty straightforward: soy oil is degummed, which simply means it is mixed with water in order to partly separate its lecithin component, then this component is dried into a powder.

Finally, some people don’t have anything against soy lecithin unless it is sourced from genetically modified (GMO) soy. Ignoring the GMO safety debate, soy lecithin is so far removed from soybeans that it contains little to no genetic material and can’t be traced back to the soybeans from which it came. So any concerns over GMOs are irrelevant to soy lecithin.

Really, the only potential concern with soy lecithin is allergy. Soy protein is a common allergen, but as we said, commercial soy lecithin contains very little residual protein: a mere 100–1,400 parts per million (according to the European Lecithin Manufacturers Association, de-oiled soya lecithin is just 0.000065–0.00048% protein). Tested against the immune cells of adults with a soy allergy, soy lecithin caused little to no reaction.

Only two isolated case reports document allergic responses, both in toddlers: one toddler got an allergic response from an allergy test (100 mg of soy lecithin), the other from infant formulas (the three formulas mentioned were 1%, 0.9%, and 0.56% soy lecithin; the Codex Alimentarius limits the lecithin content of formulas to 500 mg per 100 ml of prepared beverage).

Overall, soy lecithin used as a food additive contributes such a minuscule amount of protein that it is generally considered safe for people with soy allergies. That said, everyone is different: if, for any reason, soy lecithin really doesn’t agree with you, then avoid it. Just know that most people don’t have to.


Some protein powders include thickening agents to create a creamier shake. Approved thickeners include starches (corn, potato, tapioca ...), gums (xanthan, guar, locust bean ...), and sugar polymers (pectin, agar, carrageenan ...).

There isn’t much to say about the starches because they are likely used in quantities too low to have a notable nutritional impact. At most, they might add a gram or two of carbs per serving. Gums are also not much of a health concern. In large amounts, they act as soluble fibers: they bind to water, increasing viscosity and slowing digestion, and can thus lower post-meal blood-sugar response if the meal contained carbs. But the doses used in protein powders are way too small to have any noticeable effect.

The one thickener that should give you pause is carrageenan. Although it has been granted generally recognized as safe (GRAS) status by the FDA, there are still gaps in our understanding of this sugar polymer. Toxicological reviews deem it safe at incredibly high doses,180 around 18–40 milligrams per kilogram of body weight (mg/kg), but concerns remain about how it interacts with the digestive system when consumed in a solution, such as a whey protein shake, rather than in solid food.

There are reasons to believe that carrageenan may worsen gut problems (e.g., inflammatory bowel disease or irritable bowel syndrome), might harm the gut microbiome, and might promote inflammation in the colon. The amounts of carrageenan used in whey protein powders would likely be low and probably of little concern, but we don’t really know. Minimizing exposure may be prudent.

Artificial sweeteners

Artificial sweeteners are synthetic sugar substitutes that are many times sweeter than sugar but have little to no caloric value and generally do not affect blood sugar. There are currently six FDA-approved artificial sweeteners: acesulfame potassium (Ace-K), advantame, aspartame, neotame, saccharin, and sucralose.

FDA-approved artificial sweeteners

An in-depth discussion on artificial sweeteners is beyond the scope of this guide, but we do want to address some of the common areas of controversy, starting with general safety.

The FDA has set an Acceptable Daily Intake (ADI) for each artificial sweetener after evaluation of the chemical’s toxic and cancer-causing effects. Depending on how much protein powder you consume and how much sweetener it contains, the ADI may or may not be something to worry about. Of course, you also need to factor in other foods if they contain the same sweetener.

Unfortunately, manufacturers seldom list the amount of sweetener in a food or supplement. In theory, since ingredients must be listed by weight (from heaviest to lightest), you can get a general idea of how much sweetener a product contains, but only if you can guess the amounts of the surrounding ingredients.

Another issue worth mentioning is the link observational data found between consumption of artificial sweeteners and obesity. Fortunately, it can certainly be explained by reverse causality: it isn’t that people who use artificial sweeteners are more likely to become overweight, but that overweight people are more likely to use artificial sweeteners (in an attempt to lose weight). As it stands, intervention studies have consistently shown that artificial sweeteners do not cause weight gain; on the contrary, they commonly reduce energy intake and promote weight loss.

The one exception appears to be saccharin, which was recently shown to promote weight gain to the same extent as table sugar over 12 weeks, while sucralose, aspartame, and stevia did not. All five of the sweeteners were consumed in a beverage in amounts within the acceptable daily intake limits. However, diet wasn’t controlled, so it is possible that food intake was higher in the saccharin group than in the sucralose, aspartame, and stevia groups, especially considering that, over the course of the study, hunger was greater in the saccharin group than in the four other groups. In other words, it is possible that saccharin promotes weight gain indirectly by increasing hunger, but this hypothesis would need to be verified in specially designed studies.

Lastly, there are concerns over artificial sweeteners interfering with glycemic control and reducing insulin sensitivity. These concerns seem to stem mainly from studies on sucralose showing that a realistic daily intake of 150–200 mg reduces insulin sensitivity in healthy adults. A previous study, however, had found no such effect from a much higher daily intake (1,000 mg), so the data are conflicting and the question remains unresolved.

Frankly, this entire discussion is somewhat moot since finding protein powders void of artificial sweeteners isn’t difficult, if that’s what you want.

Natural nonnutritive sweeteners

Natural nonnutritive sweeteners are naturally occurring sugar substitutes that are many times sweeter than sugar but have little to no caloric value and generally do not affect blood sugar. The FDA has granted generally recognized as safe (GRAS) status to two such sweeteners: steviol glycosides, from the leaves of the Stevia rebaudiana plant, and mogrosides, from Siraitia grosvenorii (luo han guo, or monk fruit).

FDA-approved natural nonnutritive sweeteners

Importantly, the FDA approved only stevia extracts that are more than 95% steviol glycosides. Stevia leaves and crude stevia extracts are not GRAS; they cannot be sold as sweeteners in the US. This is important because stevia’s adverse effects, such as a decreased testosterone, are linked to the stevia leaf, not to steviol glycosides.

Steviol glycosides include notably Rebaudioside A (also known as Reb A) and stevioside. They are resistant to your digestive enzymes; they pass intact through your gastrointestinal tract, breaking down only after coming into contact with your colon’s microbiome. The microbes (the bacteria) remove and metabolize the sugar molecules from the steviol backbone, which is then absorbed into your blood, metabolized within your liver, and excreted in your urine.

Far less research has focused on the monk fruit and its sweet-tasting mogrosides. Although monk fruit extracts have been granted GRAS status by the FDA, and have long been used in traditional Chinese medicine, further research is necessary to determine their potential health effects and safe upper intake levels.


Polyols (sugar alcohols) are another class of sweeteners (sugar substitutes). The six polyols most used as sweeteners are erythritol, lactitol, maltitol, mannitol, sorbitol, and xylitol; compared to sugar, they are 30–100% as sweet, lower in kilocalories (0.2–2.7 per gram, instead of 4), and lower on the Glycemic Index (meaning they have a lesser effect on blood sugar).

Most common polyols

Except for erythritol, polyols may cause bloating and diarrhea when consumed in excess, since they are only partially absorbed in the gastrointestinal tract and are rapidly metabolized by the microbiome in the colon.

Preliminary evidence suggests that erythritol and, to a lesser extent, xylitol may help prevent dental plaque and cavities, but more studies are needed for confirmation and to determine an optimal protocol, amount, frequency, and exposure time (relevant studies use polyols mostly in chewing gums or hard candies, to ensure prolonged dental exposure).

Natural and artificial flavorings

Protein powders come in all kinds of flavors. Historically, natural flavorings were called extracts, tinctures, or essential oils; most are isolated from plants. Artificial flavorings are synthesized in a lab; most contain the exact same molecules that exist naturally in foods or are formed during food preparation, but some molecules are only structurally similar.

A flavoring is usually a combination of more than 50 molecules. Rarely does a flavor originate in a single molecule, as in the case of vanilla (vanillin), strawberry (ethyl methylphenylglycidate), or green apple (hexyl acetate).

Contrary to popular belief, artificial flavorings are probably safer than natural ones, which are more likely to vary in their composition and to contain impurities. A natural vanilla extract, for instance, is a mixture of several hundred different molecules in addition to vanillin.

Still, whether natural or artificial, the thousands of flavorings used by the food industry are generally recognized as safe (GRAS). To be granted GRAS status, a flavoring molecule must undergo evaluation of its chemical structure and physicochemical properties, purity and manufacturing process, natural occurrence in foods, potential exposure level, metabolism, toxicology, and gene-damaging potential.

If information for criteria is not available, however, a flavoring, whether natural or artificial, may still be granted GRAS status based on the structural similarity of its molecules to other, tested molecules. It means that GRAS status can be granted to untested molecules and untested combinations of molecules (the actual flavorings).

Furthermore, flavorings are granted GRAS status by the FDA based on assessments by a scientifically independent Expert Panel funded by the Flavor and Extract Manufacturers Association. In other words, while the FDA has the last say, it does not assess the flavorings itself. In the past, it has banned several artificial flavorings only after being petitioned for their removal from the food supply due to some animal studies suggesting their being carcinogenic.

This serves to show that flavorings can pose health issues and that their safety evaluation isn’t always thorough. The sheer number of chemicals used as flavorings makes testing each and every one a daunting task, and since most are used only rarely, there is little economic incentive to support a traditional toxicology battery (meaning that too many flavorings are granted GRAS status based on structural similarities, as explained above).

Natural and artificial colorants

Without food colorants, all whey protein powders would share a similar off-white color, regardless of the included flavorings.

Seemingly innocuous, food colorants are probably the most rigorously regulated food additives in the world. Unlike flavorings, they can’t simply be granted GRAS status; they are assessed by the FDA directly, so the safety evaluation they undergo is much stricter.

As with flavorings, there are two general categories of food colorants: natural and artificial.

Natural colorants are derived from natural sources, mostly plants; they include β-carotene, annatto, paprika, turmeric, and beet powder, among many others. They’re considered safe and are seldom controversial (one exception being E120, a red colorant derived from an insect, the cochineal).

Conversely, artificial colorants, or food dyes, are often controversial, notably because different countries using different approval methods. For example, of 18 food dyes approved by either the FDA (in the US) or the EFSA (in the EU), only 6 are approved by both agencies.

A notable topic of controversy, the effect of food dyes on attention-deficit hyperactivity disorder (ADHD) in children was heavily investigated in the ’70s and ’80s. The most recent meta-analysis dates from 2012: it includes 20 double-blind randomized controlled trials and concludes that food dyes slightly promote hyperactivity in children. The authors speculate that 8% of children with ADHD may benefit from eliminating dyes from their diets.

Still, the association between food dyes and ADHD isn’t entirely clear, for at least three reasons.

First, it hasn’t been investigated in adults.

Second, food dyes appear to worsen ADHD only in children with certain genes.

Third, most studies have used a dye mixture, leaving open the possibility that only some dyes worsen ADHD.

Aside from potentially worsening ADHD in children, food dyes approved in the US have been shown to be carcinogenic or genotoxic (damaging to genetic material) to varying extents, and they can also cause hypersensitivities and allergic reactions in susceptible individuals. For example, Blue #1, Red #40, Yellow #5, and Yellow #6 can cause allergic reactions, and both yellow dyes also contain benzidine, a carcinogen.

These findings suggest that the safety evaluation of food dyes, though stricter than the safety evaluation of flavorings, is still inadequate. Many of the studies the FDA used to declare food dyes safe were conducted by dye manufacturers, were too short to adequately assess carcinogenicity, and tested each dye only in isolation (whereas dyes are often combined).

Natural colorants are not a concern, but there are data linking some artificial colorants (food dyes) to cancer, genotoxicity, allergies, and behavioral alterations. While nothing conclusive can be drawn from the available research, it seems prudent to avoid food dyes whenever possible.

Digestive enzymes

Proteases are digestive enzymes that break down proteins. They are used in some protein powders to increase the bioavailability of the protein. Two studies have investigated this topic, both completed by the same research lab and funded by Triarco, the company that patented the tested product (Aminogen®, a blend of proteases isolated from the fungi Aspergillus niger and Aspergillus oryzae).

The first study assessed how adding Aminogen® to whey protein concentrate affected serum levels of amino acids during the 4 hours following ingestion. Two groups of 21 healthy young men took 50 grams of whey protein twice: first on its own, then, nine days later, with Aminogen® — 2.5 grams for one group, 5 grams for the other. Both doses resulted in similarly higher serum levels of amino acids, suggesting that the benefit tops out at 2.5 grams or less.

The second study was a randomized controlled trial involving 36 resistance-trained men who took 40 grams of whey protein concentrate twice daily (80 g/day) for the 4 weeks of a resistance-training program. One group of 18 men took only whey protein; the other took whey protein blended with 1.5 grams of Aminogen® (3 g/day). Minimal differences in clinical markers of cardiometabolic health and liver and kidney functions were seen between the groups.

Neither study tells us much. The effects are small to nonexistent, and useful parameters such as MPS and lean body mass were not assessed. Plus, while there are many types of digestive enzymes, only a single, specific blend of two was tested. At this time, there isn’t strong evidence supporting the use of digestive enzymes in whey protein powders, although this area of investigation remains largely unexplored.

On a final note, even if Aminogen® had been proven to make a practical difference, dosage would still be an issue. At least one lawsuit was filed against a company for using less than 0.1% of Aminogen® in their whey protein product; the company lost the case because the above studies used concentrations 36–91 times greater (3.6–9.1%).

Hope the above helps you.

Coach HB

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