GPLC ineffective at 3g/day (study)
- 09-23-2010, 09:09 AM
GPLC ineffective at 3g/day (study)
Effect of glycine propionyl-L-carnitine on aerobic... [Int J Sport Nutr Exerc Metab. 2008] - PubMed result
Effect of glycine propionyl-L-carnitine on aerobic and anaerobic exercise performance.
The purpose of this study was to evaluate the effect of glycine propionyl-L-carnitine (GPLC) supplementation and endurance training for 8 wk on aerobic- and anaerobic-exercise performance in healthy men and women (age 18-44 yr). Participants were randomly assigned to 1 of 3 groups: placebo (n=9), 1 g/d GPLC (n=11), or 3 g/d GPLC (n=12), in a double-blind fashion. Muscle carnitine (vastus lateralis), VO(2peak), exercise time to fatigue, anaerobic threshold, anaerobic power, and total work were measured at baseline and after an 8-wk aerobic-training program. There were no statistical differences (p> .05) between or within the 3 groups for any performance-related variable or muscle carnitine concentrations after 8 wk of supplementation and training. These results suggest that up to 3 g/d GPLC for 8 wk in conjunction with aerobic-exercise training is ineffective for increasing muscle carnitine content and has no significant effects on aerobic- or anaerobic-exercise performance.
- 09-23-2010, 04:13 PM
09-23-2010, 04:30 PM
Well, for starters, all of their exercise for the 8 weeks was aerobic - no weight training. also, from the abstract you can't tell how large each group was. If they were groups under 6 each (so 18 total) then I wouldn't put a lot of credence in it.
09-23-2010, 04:47 PM
"8 wk on aerobic- and anaerobic-exercise performance in healthy men and women (age 18-44 yr). Participants were randomly assigned to 1 of 3 groups: placebo (n=9), 1 g/d GPLC (n=11), or 3 g/d GPLC (n=12), in a double-blind fashion. Muscle carnitine (vastus lateralis), VO(2peak), exercise time to fatigue, anaerobic threshold, anaerobic power, and total work were measured at baseline and after an 8-wk aerobic-training program."
09-23-2010, 04:56 PM
09-23-2010, 05:22 PM
09-23-2010, 05:28 PM
09-23-2010, 05:34 PM
Is there even one study saying any of these type of products do anything?
Shawn Ray posted another study from another one these type products that showed it did jack sh*t as well. If you wanna "feel" something then buy it though.
09-23-2010, 05:54 PM
09-23-2010, 06:05 PM
09-23-2010, 06:07 PM
You guys realize that it was GPLC at 4.5 grams/day that was shown to have the purported effects, right?
This study used up to 3 grams/day...
This could be debated all day long in the end, but until more independent 3rd party studies are completed you can't really say either way; but I don't see how this refutes anything when it's not even the same dosage parameters used. This study has its flaws right off the bat from a statistical significant standpoint...Just for starters, this is way too small of a sample size (n=) to seriously conclude anything of remote significance (the other study has this same flaw). I can speak from my own experiences that I have had very good effects with GPLC dosed at 4.5 grams/day.
Evolutionary Muse - Inspire to Evolve
09-23-2010, 06:11 PM
09-23-2010, 06:14 PM
09-23-2010, 06:15 PM
09-23-2010, 06:17 PM
In the present study, we sought to determine the impact of oral GPLC on plasma NOx at rest and in response to a period of reactive hyperemia in resistance trained men.
Using a double blind, crossover design, 15 healthy men (24 ± 4 years) were assigned to GPLC (3 g/d PLC + 1044 mg glycine) and a placebo in random order, for a four-week period, with a two-week washout between condition assignment. Blood samples were taken from subjects at rest and at 0, 3, and 10 minutes following an ischemia-reperfusion protocol (six minutes of upper arm cuff occlusion at 200 mmHg followed by rapid reperfusion with cuff removal). Blood samples were taken from a forearm vein from the same arm used for the protocol and analyzed for total nitrate/nitrite. Data are presented as mean ± SEM.
A condition main effect (p = 0.0008) was noted for NOx, with higher values in subjects when using GPLC (45.6 ± 2.8 μmol·L-1) compared to placebo (34.9 ± 1.2 μmol·L-1). No time main effect was noted (p = 0.7099), although values increased approximately 12% from rest (37.7 ± 2.7 μmol·L-1) to a peak at 10 minutes post protocol (42.3 ± 3.3 μmol·L-1). The interaction effect was not significant (p = 0.8809), although paired time contrasts revealed higher values for GPLC compared to placebo at 3 (48.2 ± 6.7 vs. 34.9 ± 2.4 μmol·L-1; p = 0.033) and 10 (48.8 ± 5.9 vs. 35.7 ± 2.1 μmol·L-1; p = 0.036) minutes post protocol, with non-statistically significant differences noted at rest (41.8 ± 4.5 vs. 33.6 ± 2.5 μmol·L-1; p = 0.189) and at 0 minutes (43.6 ± 5.1 vs. 35.4 ± 2.7 μmol·L-1; p = 0.187) post protocol. An analysis by subject (collapsed across time) indicated that 11 of the 15 subjects experienced an increase in NOx with GPLC treatment.
These findings indicate that short-term oral GPLC supplementation can increase NOx in resistance trained men. However, as with many dietary supplements, there exist both "responders" and "non-responders" to treatment. Future work may focus on the mechanisms for the discrepancy in response to GPLC supplementation for purposes of NOx elevation.
Who was questioning the size of the current studies test pool, hmmm?
09-23-2010, 06:21 PM
09-23-2010, 07:02 PM
Here's what I find interesting: Sigma Tau performed two marginal studies on THEIR product which demonstrated some effectiveness. This board grabbed it and ran, like it was the second coming of Vishnu. Feedback is somewhat mixed. When faced with the study in this thread, the answer is 'whatever, my **** works'. Maybe so, I'm not saying it doesn't. But it's ironic, when you consider the whole arginine debacle ( ); studies are 50/50 as to whether it works or what it actually does, but when people chime in with 'it just works', it's ridiculed.
Hey, it'd be awesome if it was clinically proven to work. But 2 positive, miniscule studies out of 3 isn't that awesome. I'll sit here and enjoy my NO free ASGT.
09-23-2010, 07:55 PM
09-23-2010, 08:02 PM
09-23-2010, 08:06 PM
09-23-2010, 08:28 PM
Sure, but I've only seen one study on plcar and vasodialation, and it was in vitro, and had nothing to do with nitric oxide. Not that adding glycine couldn't change that, but if we're relying on plcar studies now...
09-23-2010, 11:51 PM
I think PLCAR showed superiorness (thats a word starting right now) in fat loss over all other carnitines...but GPLC doesnt make any claims with fatloss I dont think. It is a different molecule after all
09-24-2010, 01:41 AM
09-24-2010, 01:51 AM
BTW...nice word Natty
"Never trust a b*tch because b*tches be crazy, now get out there and go crush some P***Y!" - Jerry Stiller.
09-24-2010, 01:58 AM
09-24-2010, 02:20 AM
Like I said from the getgo with all those companies trying use little amounts of it, 4.5-5gs is where its at, using more will not give more results based on study done some time ago. Anyone who thinks 3gs or less is good is on placebo and belief preserverance.
doing my own thang!
09-24-2010, 08:40 AM
09-24-2010, 08:45 AM
Looks like they have some other weird products as well.
Also, a patent search shows that Sigma Tau has the patent (not pending, but passed) for both GPLC and PLCAR
09-24-2010, 08:55 AM
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