Is glycine a safe dietary supplement? read a while ago about some connection with cancer but have also read that it is beneficial for longevity. have taken it quite a bit as it has a good effect on sleep. (2g)
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Yes. As its not unusual for seniors to ve lacking. Other drugs like SSRI decrease the hepatic conversion to synthesize glycine. Do a search there is another long thread discussing it. I use between 2-10g/d. Its nice as it hasa mildly sweet taste so compared to 99% of supplements it tastes pleasant and you just use a scoop into your mouth and let it disolve and swallow.
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Glycine, however, is often one of the main amino acids in collagen powder. Hence if you take sufficient collagen supplementing with Glycine additionally may not be much use.
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Here’s the thread
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Glycine is safe regarding cancer. Serine is not.
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Do we need to get extra glycine if we already consume collagen peptides simultaneously with NAC?
It depends on the type of collagen and how much. If you are taking 2X or more grams of collagen than NAC, I’d say that’s the minimum. I’d probably want to see 3-4X to fully utilise the NAC.
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In fact glycine can be helpful in cases of liver cancer as supplying enough glycine downregulates the enzyme serine hydroxymethyltransferase (SHMT) which is normally used to syntheize glycine. SHMT is known to increase proliferation of malignate cells.
Here is a good explanation of the entire various pathways involved:
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It may be. Glycine at 8% diet extended both median and maximum lifespan in rats by roughly 30%. And rats may be a better model for gerontological research than mice. (Allometric scaling needed for human dosing estimate).
Study Title: “Dietary glycine supplementation mimics lifespan extension by dietary methionine restriction in Fisher 344 rats.”
The FASEB Journal 25, 528.2-528.2, 2011. Joel Brind, Virginia Malloy, Ines Augie, Nicholas Caliendo, Joseph H Vogelman, Jay A Zimmerman, Norman Orentreich
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Thank you very much for all the answers!
Dosing estimate based on allometric scaling. Note that this is for glycine alone, not with NAC.
Glycine at 8% diet is 80,000 ppm feed.
To convert from ppm feed in rats to mg/kg bodyweight in humans:
Step 1: Convert PPM in rat chow to mg/kg bodyweight in rats by multiplying by a factor of 0.05:
80,000 × 0.05 = 4000 mg/kg (*)
Step 2: Apply allometric scaling to convert from rat to human (divide by 6.2):
4000 mg/kg ÷ 6.2 = 645.16 mg/kg. (**)
Step 3: Multiply by human weight in kg to determine personal dosage estimate. For example, a 70 kg person:
645.16 mg/kg × 70 kg = 45,161.2 mg. Approximately 45 grams daily in divided doses for a 70 kg person.
Tables:
Sources:
(*) Nair A, Morsy MA, Jacob S. Dose translation between laboratory animals and human in preclinical and clinical phases of drug development. Drug Dev Res . 2018;79(8):373-382. doi:10.1002/ddr.21461.
(**) Nair AB, Jacob S. A simple practice guide for dose conversion between animals and human. J Basic Clin Pharm. 2016;7(2):27-31. doi:10.4103/0976-0105.177703
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Glycine mimics meth, nine restriction diet. Selenium also mimics methionine restriction diet. Selenium supplementation inhibits IGF-1 signaling and confers methionine restriction-like healthspan benefits to mice - PMC
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However too much Selenium is toxic. Too much Glycine is not.
It’s hard to get 45 g of Glycine daily, and, honestly, that seems like way too much. I always thought 15 g (which I take daily) was already quite a bit!
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This high of a dose would need to be divided. For example, if someone weighed 70 kg and wanted to take 45 grams daily, then 15 grams every eight hours. Or dividing into four doses. Studies have used up to 90 grams daily for extended periods. However, that is in divided dosages. If this much was taken all at once, it may produce mild toxicity like mental fatigue and probably wouldn’t serve its purpose for anti-aging, because the idea would be to keep replenishing the liver with fresh glycine and not OD’ing in a single bolus. I’m not necessarily advocating such a high dose as the 45 gram amount, but I did the calculations to show what it would be with basic allometric scaling.
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I understand and agree. Even with 15 g daily, I break it up into 2-3 doses.
That logic does not make sense, if you take too much vitamin D for example that is also toxic If you take too much. Selenium has its place as an anti-aging benefit. Especially as a methionine restriction mimicker.
Of course Selenium has it’s place. It just has a much lower threshold before it goes from a benefit to a detriment. I take Selenium, but I make sure not to take too much. Glycine has a much higher threshold.
I would concede that you are right. There is a point where everything can be taken in too high of a quantity. However, I would argue that if you take 45 g of Glycine and 45 g of Selenium daily, the Selenium is going to cause you problems a lot sooner. The former is safe. The latter is dangerous.
The issue is how close in dosages is what gives optimal positive effects and the dose that causes toxic effects. Further is the toxic effect acute or does it require more chronic dosing.
I also agree that selenium is far easier to overdose than glycine. Simply eating an couple extra brazil nuts each day can cause toxic effects. Thats has its own set of issues in that most people would never think 3-5 indivual nuts per day could cause selnium toxicity.
Fentanyl dosing regardless that its in mcg the dose that creates effective pain control or sedation for procedures abd the dose that causes significant respitory supression is very small and highly variable, morphine or even hydromorphone (Dilaudid) has a much larger window in pain control vs sedation/respitory suppression. This is why most hospitals changed their policy and fentanyl can only be admistered in the ER or ICU where patients have constant monitoring. These changes were long before China started dumping metric tons of it onnthe streets so it was not from DEA or gov political pressure.
Glycine would take large dosages and extended chronic dosing at that level to eventually have toxic effects possibly thru its metabolites or some pathway effect of chronic suppression or activation. Choice between downing a bottle of selnium vs a tub of glycine, I will take glycine everytime. Plus it tastes good, mildly glucose sweet.
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Aside from the rat study, 8% glycine diet was also tested in mice in the ITP study at three sites as previously mentioned. And it extended lifespan at all three sites, but the effects were modest in comparison. The researchers noted that in the mice supplemented with 8% glycine, “there is no evidence from this work that glycine supplementation impairs health.” Source
With regard to rats, they may be a better choice than mice for lifespan studies.
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