The amino acids thread (which ones are good, which are bad)

For a long time, we’ve all believed glycine GOOD, Methionine BAD, BCAAs BAD. Though in ARDD2022 dudley lamming showed isoleucine worse than leucine

Several amino acids (AAs) have been shown to be associated with insulin resistance and increased risk of type 2 diabetes, but no previous studies have investigated the association of AAs with insulin secretion in a longitudinal setting. Our study included 5,181 participants of the cross-sectional METabolic Syndrome In Men (METSIM) study having metabolomics data on 20 AAs. A total of 4,851 had a 7.4-year follow-up visit. Nine AAs (phenylalanine, tryptophan, tyrosine, alanine, isoleucine, leucine, valine, aspartate, and glutamate) were significantly (P < 5.8 × 10−5) associated with decreases in insulin secretion (disposition index) and the elevation of fasting or 2-h glucose levels. Five of these AAs (tyrosine, alanine, isoleucine, aspartate, and glutamate) were also found to be significantly associated with an increased risk of incident type 2 diabetes after adjustment for confounding factors. Our study is the first population-based large cohort to report that AAs are associated not only with insulin resistance but also with decreased insulin secretion.

Serine: can help reduce homocysteine (but ANOTHER paper shows feeding them to ants = bad)

In Aging Science in Isolation 2022, there was a presentation on how restricting sulfur-containing amino acids was pro-longevity (and produced more heat than otherwise). This includes methionine and cysteine.

Glycine is the good one. Glycine + proline + hydroxyproline = collagen


Glycine + cysteine = lower glutamate. This is good because:

Glycine + cysteine + glutamate = glutathione which is good.

However, from the comment above it seems that cysteine is not a good AA?


Cysteine is a sulfur-containing amino acid. I think some studies show cysteine restriction can be pro-longevity.

I myself am not so sure (also not sure if restricting it is necessary when there are better targets like methionine/BCAAs), also especially due to its role in producing hydrogen sulfide and b/c the sulfur in it produces many antioxidants… (glutathionine)

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Maybe supplementing with Glycine will lower Cysteine if it all goes into production of Glutathione.

Glycine and cysteine decrease with age. Glutamate doesn’t. Therefore you need to supplement both glycine and cysteine in order to lower glutamate and increase glutathione.

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cysteine is most satiating (it’s not a BCAA!)

  • Glucogenic amino acids (aka protein): Amino acids can be divided into ketogenic (stimulate ketone production), glucogenic (stimulate glucose production), or both. Every single amino acid can be turned into glucose except for lysine and leucine, which are exclusively ketogenic. The main amino acids used for gluconeogenesis are alanine and glutamine. On average, you need 1.6 g of amino acids to make 1 g of glucose, which is expensive. That’s one of the reasons your body uses ketones during a ketogenic diet instead of amino acid-derived glucose. More on that later.

There are no bad amino acids, only good one. The best and most important ones of course the branched chain amino acids especially leucine because these build muscle. I always try to get in enough of that and with it usually come enough of the other good amino acids. Other good ones are glycine and cysteine as precursors to glutathion and arginine as a precursor to NO

you’re reducing the SN ratio of this forum with your constant simple pro-meat thinking, the BCAAs are clearly shown to be anti-longevity

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they are not, ITP did a trial with leucine supplementation there was no negative because unlike lab animals frailty kill humans. Even Blagosklonny has said that the longevity benefits calorie (and food restriction) are laboratory artifacts. (btw look at Lamming, he looks fat and weak, I wouldn’t take his advice because looking like that you won’t get very old)

And let’s be honest, you’re just lazy, you don’t want to work out but instead go for the easy solution: go on weird and extremely restrictive diets and take dozens of unproven supplements

I have a nice one for you red meat intake associated with decreased ementia risk

In contrast, a 50-g/d increment in unprocessed red meat intake was associated with reduced risks of all-cause dementia (HR: 0.81; 95% CI: 0.69, 0.95; P-trend = 0.011) and AD (HR: 0.70; 95% CI: 0.53, 0.92; P-trend = 0.009).

This paper is amazing - Amino acids in the regulation of aging and aging-related diseases - ScienceDirect

proline good, histidine good, threonine slightly good

Proline was the second most potent amino acid at extending lifespan in C. elegans (Table 1) and the most potent for increasing thermotolerance [3] suggesting that it stimulates pathways mediating proteostasis. It has been shown to extend the lifespan by transiently increasing ROS levels, which then stimulate stress response pathways that induce antioxidant gene expression [293]. Proline is hydroxylated to form hydroxyproline, a prominent amino acid in collagen, a major protein of the C. elegans cuticle [294]. Collagen remodeling was shown to be required for C. elegans lifespan extension due to daf-2 insulin receptor mutation [295].

Histidine is an essential amino acid that acts as an anti-glycating agent [187], free radical scavenger [188], and metal chelator [189,190]. The dipeptide carnosine contains histidine and beta-alanine, is found at high levels in muscle and brain, and has similar physiological properties as histidine. But carnosine was shown to be less toxic in cell culture studies, so is a more promising therapeutic [187]. Much data in model systems supports the potential use of carnosine for the treatment of aging-related disorders [191]. But we will focus on histidine as the anti-aging effects of carnosine have been previously reviewed [192]. Histidine supplementation increased insulin secretion and glycemic control, increased glutathione peroxidase activity, and decreased pro-inflammatory cytokine levels in diabetic mice [193]. Histidine supplementation increased GSH levels and enhanced catalase activity to decrease liver injury induced by chronic alcohol consumption [194]. Individual administration of histidine, cysteine, or glycine, but not alanine, inhibited NF-κB activation in cultured coronary endothelial cells [195]. Fig. 1 shows that catabolism of histidine, cysteine, and glycine influence one-carbon and redox metabolism.

Histidine can scavenge singlet oxygen and hydroxyl radicals [196]. Low plasma histidine levels have been associated with inflammation, oxidative stress, and mortality in chronic kidney disease patients [197]. A metabolomics study of human plasma found histidine levels to decline with aging in ants => has some results that do not support findings in other papers. Says supplementary AAs generally bad. Idk if ants are a better or worse model organism than C elegans (C elegans suck)