Quick Hit Summary

In Part III of our Nitric Oxide (NO) supplement series, we examine if propriety supplements that "have been synergisticically blended to create the ultimate muscle pump" are legit or not. Similar to what we saw when looking at the individual NO amino acids in Part II, these propriety supplements, often containing 100's of ingredients (ok, slight exaggeration there!) fail to pack the punch claimed by manufacturers in regards to their ability to spike NO levels. However, there is one supplement, GPLC that appears to hold some potential benefit with regard to enhancing NO production.

Nitric Oxide (NO) Article Series

In this series of articles we're going to discuss the in's and out's of the NO Supplements; covering everything from basic NO physiology to the effects of the NO amino acids in isolation, or as part of propriety blended "NO Boosting" supplements. In case you missed any of the articles, I recommend checking them out.

• Nitric Oxide Supp's Part I – Understanding the Key Players
• Nitric Oxide Supp's Part II – Let's "Pump You Up"… or Not?
• NO Supp's Part III – The "Everything But The Kitchen Sink" NO Supplements
• NO Supp's Part IV – Training Age & Supraphysiological NO Spikes
• Still to Come: NO Supp's Part V – True Potential Benefits of Citrulline Supplementation
• Still to Come: NO Supp's Part VI – True Potential Benefits of Arginine Supplementation

Looking Back At Parts I & II Of This Series

Figure 1. Are nitric oxide/ "muscle pump" supplements the key to getting that shredded/veiny body you so desire? Image source¹⁷

Thus far we've covered a lot of ground while exploring Nitric Oxide (NO) supplements. In Part I we reviewed the physiological relationship between the amino acids commonly found in these supplements – arginine, citrulline and ornithine. In Part II of this series we examined if supplementing with these amino acids actually increased blood flow and/or nitric oxide production in athletes. Although there were some interesting studies in regards to citrulline, the overall supporting scientific evidence for the other amino acids was relatively weak.

The "Everything but The Kitchen Sink" NO Supplements

Figure 2. A little of this powder, a little of that powder. Blend it together and we have a magical NO pumping powder right?!¹⁸

I know what you were likely thinking after reading Part II of this series… "OK, but who actually takes these amino acids in isolation?" To be honest with you, my guess is not too many. In fact, if you check out the label of your favorite Pre-Workout Nitric Oxide boosting supplement, you're likely to find that in addition to arginine, citrulline, etc, there are 30 bazillion other ingredients that have been "synergistically blended for maximum NO Production." Surely the addition of these ingredients will allow one to reap the muscle pumping benefits of the NO amino acids… right!?

In the 3rd part of our NO series, we'll examine the evidence supporting the muscle pumping benefits of these "Everything but the Kitchen Sink" NO Supplements. Do they really enhance blood flow or NO production in exercising individuals? Or, do they share the same ineffective fate as what we saw with the individual amino acids discussed in Part II?

Propriety NO Supplement Blends

Please Note It is relatively impossible to directly measure NO levels in the body because it reacts so quickly (1/2 life only a few milliseconds¹⁵). Thus, researchers assess NO production by measuring nitrate & nitrite levels in the body which have much longer 1/2 lives (nitrite – 1 to 5 min; nitrate – 5 to 8 hrs)⁵. These compounds are byproducts of NO and are collectively referred to as NOx. For the chemistry fans, NO (nitric oxide) + O (oxygen) <—> NO2 (nitr*i*te) + O <—> NO3 (nitr*a*te).

To my knowledge, there have only been a couple of studies that have examined the effects of propriety blended pre-workout "NO Pumping" supplements. One of particular interest, published by Bloomer et al. examined the effects of 3 popular pre-workout "muscle pumping" propriety blended supplements, as well as GPLC, on NO production, muscle tissue oxygenation, upper torso circumference & perceived muscle "pump".² The study involved 19 resistance trained men (mean age – 24 yrs) who had 7 +/- 4 years of resistance training experience. On six separate occasions each participant completed the respective training protocol randomly preceded by ingestion of:

• Baseline – nothing ingested
• Placebo – 16 g maltodextrin
• GPLC + 16 g maltodextrin
• 2 Servings of Propriety Supplement 1
• 2 Servings of Propriety Supplement 2
• 2 Servings of Propriety Supplement 3

Please note: All supplements were taken 30 minutes prior to the start of the training session per the instructions listed on the label for each respective product. The one exception to this was GPLC which was taken 60 minutes prior to exercising. The research team added the 16 g of maltodextrin in the placebo & GPLC condition as this was the mean amount found in each of the 3 respective propriety supplements. (As a side note, recall from Part II of this series that insulin, which is stimulated by maltodextrin, leads to NO release on its own.) Also, 2 servings of each propriety supplement were consumed as "the majority of users of such supplements use 2-3 servings rather than one."

As you know, here at CasePerformance, I make it a point to NOT directly state any name brand supplements as my goal is to educate vs. promote supplements (See our Q&A section for greater discussion on this subject.) However, being that I'm sure many of you are curious as to which specific supplements were used, below are the ingredient lists. A quick copy & paste search using the exact ingredient list via google will quickly answer your question

Supplement 1. Glucose Polymer Blend, Creatine Monohydrate, NO2 Complex [L-Arginine, L-Arginine Alpha-Ketoglutarate (A-AKG), L-Arginine Ketoisocaproate (A-KIC)], Guanipro™ (Guanidino Propionic Acid), Salicyclic Acid 15%, Panax Ginseng ExtractL-Tyrosine, Methylxanthines (Caffeine), NAC (N-Acetyl-Cysteine), N-Acetyl-Tyrosine, Glucuronolactone, Rhodiola Rosea Root Extract (Standardized To 5% Total Rosavins), Ginko Biloba Extract Taurine, L-Leucine, L-Glutamine, L-Valine, L-Isoleucine, L-Citruline AKG, Turkesterone (11,20 Dihydroxyecdysone From Ajuga Turkestanica Extract), Choline Bitartrate Indole-3-Carbinol, 4-Hydroxyisoleucine (From Fenugreek Seed Extract), Cinnamon Bark Extract, Bacopa Monniera,Potassium Gycerophosphate, Magnesium Glycerophosphate, Alpha Lipoic Acid, Bioperine™

Supplement 2. L-Arginine AKG, L-Citrulline Malate, RC-NOS ™ (Rutacarpine 95%), L-Citrulline AKG, L-Histidine AKG, NAD (Nicotinamide Adenine Dinucleotide), Gynostemma Pentaphyllum (Leaves & Stem) (Gypenosides 95%)Modified Glucose Polymers (Maltodextrin), Di-Creatine Malate, Trimethylglycine, Creatine Ethyl Ester Beta-Alanine Dual Action Composite (CarnoSyn®), Sodium Bicarbonate, Sodium Creatine Phosphate Matrix, Creatinol O-Phosphate-Malic Acid Interfusion, Glycocyamine, Guanidino Proplonic Acid, Cinnulin PF® (Aqueous Cinnamon Extract) (Bark), Ketoisocaproate Potassium, Creatine ABB (Creatine Alpha-Amino-N-Butyrate) L-Tyrosine, Taurine, Glucuronolactone, Methylxanthine (Caffeine), L-Tyrosine AKG, MCT's (Medium Chain Triglycerides)[Coconut], Common Periwinkle Vinpocetine 99%, Vincamine 99%, Vinburnine 99% (Whole Plant) Di-Calcium Phosphate, Di-Potassium Phosphate, Di-Sodium Phosphate Potassium Glycerophosphate, Magnesium Glycerophosphate, Glycerol Stearate

Supplement 3. D-Glucose Monosaccharide, L-Arginine, Taurine, L-Aspartic Acid, Disodium Phosphate, Dipotassium Phosphate, Dicalcium Phosphate, Xanthinol Nicotinate, L-Arginine Ketoisocaproic Acid, L-Arginine Ethyl Ester HCL, LNorvaline, L-Norvaline Ethyl Ester HCL, Citrulline Malate, L-Citrulline Ethyl Ester L-Histidine Alpha-Ketoglutarate, Gynostemma Pentaphyllum Extract (Root) (Standardized To 85% Gypenosides), Acetyl L-Carnitine L-Arginine Dihydrochloride, Artichoke Extract (As Cynara Scolymus L.)(Root) Standardized To 5% Chlorogenic Acid, Crataegus Pinnatifida Bunge Extract (Fruit) Maltodextrin, Creatine Monohydrate, Creatine Anhydrous, Creatine Malate, Creatine Taurinate, Creatine HCA, Creatine L-Pyroglutamate, Taurine Ethyl Ester HCL, Taurine Alpha-Ketoglutarate, 18 Beta Glycyrrhetinic Acid, Coriolus Versicolor Powder (Plant) Glycine, L-Leucine, L-Isoleucine, L-Valine, Beta Alanine, Beta Alanine Ethyl Ester HCL, L-Leucine Methyl Ester HCL, L-Leucine Alpha-Ketoglutarate, L-Leucine Isovaleric Acid, L-Isoleucine Ethyl Ester HCL, L-Isoleucine Methyl Ester HCL, L-Valine Ethyl Ester HCL, L-Valine Alpha-Ketoglutarate, Alpha Amino N-Butyrate Caffeine Anhydrous (Standardized For 117 Mg Caffeine), Yerba Mate Powder (As Llex Paraguariensis)(Leaf), NAcetyl- L-Carnitine HCL, Yohimbine HCL (Pausinystalia Yohimbe)(Bark), Evodia Rutaecarpa Extract (As Tetradium Ruticarpum)(Fruit) (Standardized For 10% Evodiamine), Black Tea Extract (As Camellia Sinensis)(Leaf) (Standardized For 70% Polyphenols, 50% Catechins, 25% EGCG), Theobroma Cacao Extract (Seed) (Standardized 6% Theobromine), White Tea Extract (As Camellia Sinensis)(Leaf) (Standardized For 50% Polyphenols, 35% Catechins, 15% EGCG), White Willow Extract (As Salix Alba)(Bark) (Standardized For 25% Salicin) N-Acetyl-L-Tyrosine, L-Tyrosine, Sulbutiamine, Vinpocetine, Alpha Glycerophosphocholine, Cis-9, 10 Octadecenoamide, Huperzine-A (As Huperzia Serrata)Quercetin Dihydrate, Dihydroxy-Diosgenin (25R-5 Alpha-Spirostan-2-Alpha, 3-Beta), N-Acetyl L-Cysteine, NAcetyl-5-Methoxytryptamine

Like I said, these are your "everything but the kitchen sink" type of supplements that have been synergistically blended to give you "amazing muscle pumps" ;-)

After consuming their respective supplements, waiting 30- 60 minutes, and completing a warm-up, the subjects performed 3 bench press throws (30% 1RM; 90 second rest b/w sets). This was followed 10 sets of bench press taken to muscular failure (50% 1RM; 2 min rest b/w sets). With respect to measurements, blood samples were taken prior to ingesting each supplement as well immediately following the exercise session (~ 60-70 min following ingesting of propriety blends; ~ 90-100 min following GPLC <—- I'm guessing a little bit on these based off the study description). Muscle tissue oxygenation was assessed after each set of bench press taken to failure. Measurements of the "muscle pump" (participants perceived perception of a muscle pump (1-10 scale) & upper torso circumference measured at nipple line) were assessed prior to and at the completion of the training session.

Upon completion of the study, the research team found that all of the supplements FAILED to live up to their NO muscle pumping claims. No significant differences were between groups with respect to markers of nitric oxide production (Figure 3), upper body circumference (Figure 4) or perceived sensation of experiencing a muscle pump (Figure 5). In addition, although some minor differences were noted, muscle oxygenation was relatively the same under all testing conditions. Thus, making the claim that these particular NO supplements enhance oxygen delivery to exercising muscles false.

Figure 3. Serum Nitrate/Nitrate (NOx), markers of NO production, upon following each supplement protocol. No significant differences noted between testing conditions. Image created by Sean Casey

Figure 4. Upper torso circumference, measured at nipple line, upon following each supplement protocol. No significant differences noted between testing conditions. Image created by Sean Casey

Figure 5. Perceived muscle pump upon following each supplement protocol. No significant differences noted between testing conditions. Image created by Sean Casey

To my knowledge, the only other study that has examined a propriety blended supplement on NO production is that completed by Bailey et al.³. In their crossover designed study, Bailey et al had 9 recreational males (mean age – 26 yrs) consume 3 days of a propriety blended supplement (ingredient list below) or a placebo in conjunction with a 3 day cycling sessions. Day 1 of the session consisted of two 6 minute intervals riding at moderate intensity; Day 2 consisted of one 6 minute interval at moderate pace + one 6 min bout of intense cycling; Day 3 was the same as day 2 except the second cycling bout was done till exhaustion. 25 minutes separated each cycling bout. Blood samples were drawn prior to each cycling interval (ie- 2x/day; the first ~ 60 min post ingestion & the 2nd ~90 minutes post ingestion). Final results indicated that on average, the ingestion of the propriety supplement did lead to a 108% greater NO production vs. placebo. Unfortunately no measures of blood flow or volume were measured by the research group.

Ingredients. The authors did not disclose the ingredient list. Rather they stated that it was "a 20-g dose of the ARK 1 supplement, which contained 6 g of L-arginine, along with trace amounts of vitamins (E, C, B6, and B12), other amino acids (L-glutamine, L-leucine, L-valine, L-carnitine, L-citrulline, L-cysteine, and L-isoleucine), and fructose (11g)." By doing the math, take away the arginine and fructose, we're left with 3 grams that is divided amongst all those other ingredients.

What explains the surprising results of increased NO production observed by Bailey et al. you ask? First off, the intensity of this exercise protocol was more intense than that described in the previous study which had 2 minute rest breaks between bench press sets. With a higher "ceiling" for NO needs in the Bailey et al study, one may expect that a potential NO supplement may bring about greater NO production. It could also be related to acute/novelty of the supplement to the participants similar to that observed in the Alvares et al. study discussed in Part II .⁴ I have yet to see a long term study showing similar results. And, if you talk to individuals who feel that they initially get a "pump" out of their supplement, many feel it wears off with chronic use. ( In addition as I'll discuss in Part IV of this series, the likelihood of actually seeing an effect is even less in well trained individuals.) However, before we get too carried away with the results of this study, it's important to mention a significant caveat of the study. The research team FAILED to assess baseline NO levels. As aforementioned, the first blood sample was taken AFTER the participants took either the supplement or placebo. Thus, the results of this study could have been simply explained by higher initial levels of nitrate in the blood while taking the supplements simply due to their diet.

Our diet is a source of both nitrites and nitrates. As a whole, nitrates are found most commonly in plants such as leafy greens, spinach, beets particularly whereas nitrites are found in meat products.⁵⁶ For a list of nitrate/nitrite content of various foods check out tables 2,3,4,5 in this article. The authors of this journal article hypothesize that some of the beneficial effects of vegetables and fruit on cardio vascular health may be related to their nitrate/nitrite content. As mentioned earlier in this article, nitrite and nitrate can be converted into NO. Additionally, soon, if not already, you may come across nitrate rich beetroot juice at your favorite supplement store. For greater discussion on this topic, I refer you to my friend Adel Moussa's article which examines some of the research on these supplements.

What's the Deal With That GPLC Stuff?

Glycine propionyl-l-carnitine, commonly referred to as GPLC, is a more recent addition to the NO supplement field. As the name indicates, this supplement is made out of glycine and propionyl-l carnitine, both of which have been implicated in vasodialation in either in-vitro tests or when administered via IV⁷⁸. (Side note – you may recognize the name l-carnitine which is commonly found in weight loss and brain health products. Are these legitimate? CLICK HERE to find out.)

Unlike other products on the market, GPLC appears to have some legitimate backing with respect to increasing muscle blood flow and NO production. Wait a minute… Am I not contradicting the results of the Bloomer et al. study which indicated that GPLC, along with the 3 propriety supplements, were ineffective NO supplements²?

Well, here's the catch, GPLC only appears to be an effective NO muscle pump booster when taken over time (if you recall, the first study I mentioned looked at the affects of an acute dose of GPLC. The other hypothesis is that one needs to be following a more HIIT type of training session to see the effects). This was best demonstrated in series of studies performed led by Dr. Richard Bloomer at the University of Memphis. In their first study, providing 3g/day of GPLC for 8 weeks in previously untrained, but healthy individuals (mean age ~ 26 yrs), led to increased NOx production.¹⁰ Similar beneficial effects on NOx production were also observed by his research team after giving 4.5g GPLC/day for 4 weeks to 15 healthy young resistance trained men ( ~24 yrs; training history: 5 +/- 2 hrs per week for 8 +/- 5 yrs).¹¹

The reason as to why chronic, but not acute, GPLC intake leads to enhanced NO production may help explain the mechanism by which it works its magic. Unlike arginine or citrulline, it is not directly involved in NO synthesis process that we discussed in Part I of this series. Thus, GPLC appears to assist NO production by doing more "behind the scenes" work such as reducing free radicals and affecting gene expression¹² . However, much is still to be determined on the mechanism by which GPLC works.

Now before you get too excited about the possibilities of this true NO boosting supplement and begin megadosing GPLC, I'd like to share with you the results of a final study conducted by Jacobs et al. In their study, which exemplified the golden rule of "all things in moderation", researchers randomly assigned 45 resistance trained men (= or > 2x/wk, = or >6 months training lead up to the study) to 1 of the following 3 groups:

• Group 1: 1.5 g/day; 28 days
• Group 2: 3.0 g/day; 28 days
• Group 3: 4.5 g/day; 28 days

Before and after the 28 day period, the research team assessed the participants’ anaerobic power output via 5 ten second sprints on a bike with 1 minute of active recovery between each one. Although it didn’t reach statistical significance, those in the 1.5g/day group fared much better than their counterparts. In this group, participants experienced improvements in mean power, peak power as well as peak decrement in power when comparing the before/after trial results. In contrast, both the 3.0 and 4.5g/day groups saw either no improvement or DECREASES in performance when comparing the before/after results. Mean power results are shown in Table 1.

Table 1. Mean changes in power output pre vs. post intervention during 5 bike sprints. Please note a “+” equals improvement and a “-“ equals a decrease in performance vs. equivalent sprint of pre supplement trial.

Group	Sprint 1	Sprint 2	Sprint 3	Sprint 4	Sprint 5
1.5 g GPLC/d	+ 4.9%	+ 1.7%	+ 2.7%	+2.9%	+5.1%
3.0.g GPLC/d	-1.5%	- 7.6%	-9.0%	-7.0%	-3.3%
4.5 g GPLC/d	no change	- 2.5%	-3.6%	-6.9%	-1.1%

Based off other data presented by the research group, it appears that those in the 3.0 and 4.5g/day groups experienced TOO MUCH of a muscle pump. In fact, as shown in Figure 6, with increasing GPLC doses, more complaints were made that the supplement actually caused excessive “muscle pumps” in their legs, limiting cycling performance.

Figure 6. Complaints of excessive muscle pump leading to decreased performance. For reference these percents are based off 1/12 complaining in 1.5g/d group, 5/12 complaining in 5/12 group and 7/14 complaining in 4.5g/d group. Image created by Sean Casey.

There are a few drawbacks of the study that are worth mentioning. Unfortunately, the authors failed to provide data on each groups absolute pre/post values (ie – they only reported relative changes in performance vs. absolute changes). Likewise, NOx levels were not assessed. However, in light of the other studies regarding GPLC, I think there is credence to the theory that participants literally had too much leg blood flow.

Bottom Line

Well, it appears that these propriety blends of synergistically blended ingredients packs a muscle pumping effect similar to what we saw when the individuals NO amino acids were used in isolation. Yes, 1 of the propriety blends did show benefit with an increased NOx of 108% vs. placebo but failure to mention baseline NOx levels presents itself as a major caveat and the likelihood of these effects being seen long term are not likely in my opinion.

Also, please know that the focus of this article is on these propriety supplements & their effects on muscle blood flow/NO production – not other variables. Keep this in mind as the ingredients contained in them may have ergogenic effects if properly dosed, just not related to enhanced blood flow.

Stay tuned for Part IV of this series as we clean up a few final questions regarding NO supplements; Namely, "Does one's training status effect how they'll respond to the supplements?" and "Are extreme spikes in NO, beyond that which a healthy exercising human body naturally produces on it's own even desirable?"

References

¹ Álvares TS, Meirelles CM, Bhambhani YN, Paschoalin VM, Gomes PS. L-Arginine as a potential ergogenic aid in healthy subjects. Sports Med. 2011 Mar 1;41(3):233-48.

² Bloomer RJ, Farney TM, Trepanowski JF, McCarthy CG, Canale RE, Schilling BK. Comparison of pre-workout nitric oxide stimulating dietary supplements on skeletal muscle oxygen saturation, blood nitrate/nitrite, lipid peroxidation, and upper body exercise performance in resistance trained men. J Int Soc Sports Nutr. 2010 May 6;7:16.

³ Bailey SJ, Winyard PG, Vanhatalo A, Blackwell JR, DiMenna FJ, Wilkerson DP, Jones AM. Acute L-arginine supplementation reduces the O2 cost of moderate-intensity exercise and enhances high-intensity exercise tolerance. J Appl Physiol. 2010 Nov;109(5):1394-403. Epub 2010 Aug 19.

⁴ Alvares TS, Conte CA, Paschoalin VM, Silva JT, Meirelles Cde M, Bhambhani YN, Gomes PS.Acute l-arginine supplementation increases muscle blood volume but not strength performance. Appl Physiol Nutr Metab. 2012 Feb;37(1):115-26. Epub 2012 Jan 17

⁵ Hord NG, Tang Y, Bryan NS. Food sources of nitrates and nitrites: the physiologic context for potential health benefits. Am J Clin Nutr. 2009 Jul;90(1):1-10. Epub 2009 May 13.

⁶ Griesenbeck JS, Steck MD, Huber JC Jr, Sharkey JR, Rene AA, Brender JD. Development of estimates of dietary nitrates, nitrites, and nitrosamines for use with the Short Willet Food Frequency Questionnaire. Nutr J. 2009 Apr 6;8:16.

⁷ Loffredo L, Marcoccia A, Pignatelli P, Andreozzi P, Borgia MC, Cangemi R, Chiarotti F, Violi F. Oxidative-stress-mediated arterial dysfunction in patients with peripheral arterial disease. Eur Heart J. 2007 Mar;28(5):608-12. Epub 2007 Feb 13.

⁸ Podoprigora GI, Nartsissov YR, Aleksandrov PN. Effect of glycine on microcirculation in pial vessels of rat brain. Bull Exp Biol Med. 2005 Jun;139(6):675-7.

¹⁰ Bloomer RJ, Tschume LC, Smith WA. Glycine propionyl-L-carnitine modulates lipid peroxidation and nitric oxide in human subjects. Int J Vitam Nutr Res. 2009 May;79(3):131-41.

¹¹ Bloomer RJ, Smith WA, Fisher-Wellman KH. Glycine propionyl-L-carnitine increases plasma nitrate/nitrite in resistance trained men. J Int Soc Sports Nutr. 2007 Dec 3;4:22.

¹² de Sotomayor MA, Mingorance C, Rodriguez-Rodriguez R, Marhuenda E, Herrera MD. l-carnitine and its propionate: improvement of endothelial function in SHR through superoxide dismutase-dependent mechanisms. Free Radic Res. 2007 Aug;41(8):884-91.

¹³ Jacobs PL, Goldstein ER. Long-term glycine propionyl-l-carnitine supplemention and paradoxical effects on repeated anaerobic sprint performance. Int Soc Sports Nutr. 2010 Oct 28;7:35.