The Methionine to Glycine Ratio

Updated: Mar 29, 2020

You have likely heard of the “methionine glycine ratio” by now, or “glycine methionine ratio” - what does this refer to? To understand the importance of balancing this ratio, we must discuss what is methylation and both methionine and glycine individually. We’ll then analyze key nutrients involved in methylation, and how you can eat to nurture methylation on an animal based diet.

Let’s start with methylation. Methyl-what?

What Is Methylation?

Methylation is a chemical process that occurs in the body involving the transfer of “methyl groups” (carbon atoms attached to hydrogen) from one substance to another.

Methylation is involved in several primary functions, including:

  • Helping to manage anxiety and depression

  • Promoting mood stability and mental flexibility

  • Contributing to detoxification of the liver

  • Helping to rid of histamines

  • Assisting in gene regulation

  • Aiding in maintenance and repair of new and existing tissues

primary functions involved in methylation
primary functions of methylation

These processes have a profound impact on our mental, physical, and emotional health.

The efficiency of the methylation process is affected by our diet and our genes to a certain extent.

Methionine, an amino acid especially abundant in animal proteins, is the designated methyl donor (once activated by ATP and converted to s-adenosylmethionine (SAMe)). This activation jump starts the entire methylation process. SAMe is converted to homocysteine (another amino acid) and then either rid of or recycled back into methionine. The outcome of this process is reliant on the availability of several nutrients throughout.

While we do want to ‘optimize’ our methylation to benefit from the critical functions, this isn’t as simple as just consuming more & more methionine. Like most all good things, there can be too much, and ‘too much’ methionine has its fair share of downfalls, such as the buildup of homocysteine, which is correlated with cardiovascular disease.

Methylation is extremely complex, which is where attention to detail makes a difference when constructing a diet to optimize this process.

Key Nutrients Involved in Methylation

The key nutrients involved in methylation include:

1. Methionine: An amino acid, the main methyl-donor.

2. B vitamins

  • B1 (thiamine)

  • B2 (riboflavin)

  • B2 (niacin)

  • B6 (pyridoxine)

All of the above support B12 and B9 (folate) in recycling methionine

3. Betaine & Choline: Recycle homocysteine back to methionine once the methyl has been donated.

4. Glycine: Functions as the main buffer for excess methyl groups.

5. Supporting minerals

  • Iron

  • Phosphorus

  • Sulfur

  • Magnesium

  • Potassium

  • Zinc

key nutrients involved in methylation
key nutrients involved in methylation

Optimizing your methionine to glycine ratio will help ensure all the functions of methylation are operating as desired.

Before diving into the methionine to glycine ratio, we should analyze each component individually to further understand the importance of balancing the two.


Methionine is an amino acid we obtain from protein, especially muscle meat. This essential amino acid is capable of producing several molecules with unique benefits.

Benefits of Methionine

Boosts performance: Methionine plays a role in creatine creation, which has been shown to boost strength, performance, and result in an improved muscle to fat ratio.

Improved mental flexibility and mood: Creation of SAMe (s-adenosylmethionine) supports proper function of neurotransmitters such as serotonin and melatonin.

Supports liver: Creation of PC (phosphatidylcholine) helps remove fat from the liver, preventing against fatty liver disease.

Improved cognitive performance: PC is a precursor to acetylcholine, a neurotransmitter that supports cognitive performance.

the unique properties of methionine (within the methionine to glycine ratio)

Methionine plays a critical role in methylation.

Methionine works within a system. When the other components of this system are lacking, methionine is unable to contribute properly to methylation, which can lead to depleted glycine, toxic byproducts, & reduced longevity.

Modern diets are typically high in muscle meats and low in organs, bones and connective tissues, leading to high levels of methionine, low levels of glycine, and not enough of the other critical nutrients that help process the methionine.

Now, let's detail glycine before discussing how to potentially optimize your methionine to glycine ratio.


Glycine, like methionine, is an amino acid, but it is not considered “essential” - reason being, our bodies can make glycine, so we technically do not need to consume it.

Benefits of Glycine:

Encourages muscle growth: Like methionine, glycine plays a role in creatine creation, providing muscles with fuel to repair and grow stronger

Enhances sleep: Has calming effects on the brain, increasing deep sleep and vasoactive intestinal peptide (VIP), a hormone that helps regulate the circadian rhythm

Immune system support and anti-aging: Glycine helps form glutathione, a powerful antioxidant used to prevent cellular damage and signs of aging.

Promotes healthy skin and joints: Glycine is the most abundant amino acid in collagen, which is crucial for forming connective tissue and keeping joints flexible

unique roles of glycine (in the methionine to glycine ratio)

However, it’s been estimated that our ability to produce glycine likely falls short of our daily needs and that an excess of methionine can further deplete our glycine. Our bodies adapt to states of glycine deficiency by reducing our own turnover of collagen (think: accelerated aging, arthritis, poor skin elasticity, etc.)... We don’t want that, so it would be wise to consume some external source(s) of such.

Our ancestors naturally ate a diet high in glycine through regular consumption of bones and connective tissue. Today, most of us do not, and for those of us eating a higher protein diet (1+ gram of protein per lb of bodyweight), it’s useful to understand just how much glycine we should intake to ensure we’re not impairing the proper functioning of methylation.

The suggested amounts below are based on Dr. Chris Masterjohn’s compilation and interpretation of the existing biochemistry, as well as our recommended sources of such.

Suggested Intake of Glycine

It is estimated we need from 10-60 grams of glycine a day for various reasons, including:

  • 3 grams before bed has been shown to improve sleep

  • 3-5 grams before a meal helps stabilize blood sugar

  • 15 grams of gelatin pre-workout improves collagen synthesis in joints

  • 20g per day is used to treat some rare metabolic disorders

  • 60g per day has been used to treat schizophrenia

suggested intake and sources of glycine
sources of glycine

Now what about balancing these two amino acids? The "methionine to glycine" ratio?

The Methionine to Glycine Ratio

One synergistic relationship particularly relevant in a meat heavy carnivore diet is between methionine & glycine. When working in conjunction, methionine, glycine, & certain other nutrients provide a beautiful orchestra of detoxification & enhanced protein function.

First, protein function? Proteins are made up of amino acids - the specific make-up of such determines their function in the body. It’s no doubt proteins are important, and we want all these functions working effectively to feel and look our best.

Modern diets high in methionine & low in synergistic other nutrients can result in unwanted byproducts and disfunction. Glycine is one of these components, but studies demonstrate b12, b6, & folate assist in managing high levels of methionine, as well.

Once methionine needs are met, excess is converted to glutathione *with the assistance of several nutrients, including glycine* —> glutathione is a powerful antioxidant & key regulator of protein (we want this!!), helping to prevent damage from reactive oxygen breeds, such as free radicals (don’t want these!!).

However, with low levels of glycine, instead of synthesizing glutathione, another amino acid, homocysteine, can accumulate. The build up of homocysteine is often linked to heart disease. The liver actually *requires* a “buffer system” to protect against excessive methylation and homocysteine build up. This buffer system, ya guessed it, includes glycine, choline (similar to b vitamins) & betaine (a modified amino acid that includes glycine).

Take away message: to safely handle the excess methionine potentially stemming from a high meat diet, we should balance muscle meat (methionine) with glycine, b vitamins, choline, & betaine. Our ancestors did not meticulously track how much of these nutrients they ate. Rather, eating from the whole animal naturally keeps this ratio in check.

Nutrition Practices to Improve Methylation

We can improve the process of methylation through diet. Here are a few overarching points to keep in mind when it comes to eating to nurture methylation.

1. Protein

Eat enough protien, at least 1/2 gram per pound of bodyweight, although we would suggest more, around 1 gram per pound of bodyweight.

2. Glycine

Swap some muscle meat with bone broth, collagen, gelatin, tendons, skin, or other sources of protein high in glycine.

3. Vitamins

Liver is the most complete choice and is an excellent, bioavailable source of several essential vitamins. Try smaller doses of liver frequently for consistent nutrient stores.

4. Choline & Betaine

The most abundant sources of these nutrients within an animal based diet are liver and yolks - try including both of these items into your diet regularly.

5. Folate

Folate is easily obtainable through chicken and turkey giblets, in addition to liver.

6. Digestion

Enhance absorption of all nutrients via fermented foods, taking digestive enzymes, chewing, paying attention to liquid timing, or using other aids such as apple cider vinegar - whatever helps you optimize your digestion.

nutrition practices to nurture methylation
eating to nurture methylation

Now let’s review specific amounts of each nutrients to help optimize our methionine to glycine ratio (and the methylation process) even more.

We are what we eat. Literally. What we eat can potentially “turn on” or inhibit the expression of certain genes.

Think epigenetics —> organism changes caused by modification of gene expression rather than alteration of the genetic code itself. DNA methylation is an example of this (a biochemical process discussed in the previous post).

Methylation is a major player in altering gene expression to cope with stressors from our environment, with the ability to “turn on” or “turn off” biological switches, impacting our body’s responses.

As an example, decreasing the likelihood of, say, tumor growth or cancer by “turning off” a certain gene. It is pretty cool that we can potentially affect these processes in some manner, particularly via diet.

As discussed, DNA methylation is affected most by the following nutrients:

• Methionine

• Glycine

• Betaine/Choline

• Vitamin b12

• Folate b9

• B vitamins (1, 2, 3, 6)

Increasing each of these nutrients in your diet can potentially assist DNA methylation (cool!!). On the flip side, being deficient can lead to depletion of other nutrients, toxic byproducts, & reduced longevity (not cool) by inhibiting the process of methylation from functioning properly.

See below for rich carnivore sources of each nutrient. The amounts listed are based on consuming the minimum RDA per day (which should be taken with a grain of salt). There are several things that will impact your needs: health status, absorption capacity, genetics.

Methionine: Rich in muscle meat - eating at least 1/2 your body weight in grams of protein per day will result in adequate amounts.

Glycine: Rich in bone broth, collagen & gelatin supplements, connective tissue, tendons, and pork ears, to name a few parts. Include these regularly.

Betaine & Choline:

  • 3-4 egg yolks

  • 2 duck yolks

  • 150g liver

Or some combination of the above.

eating to nurture methylation to enhance the glycine to methionine ratio
eating to nurture methylation

Folate B9: liver, raw

  • 59g turkey

  • 68g chicken

  • 138g beef

  • 174g lamb

Giblets: raw,

  • 100g chicken

  • 120g turkey

B Vitamins:

  • Thiamin (B1): 6 oz pork chop

  • Riboflavin (B2): 47g liver

  • Niacin (B3): 114g liver

  • Pyridoxine (B6): 139g liver

Almost all of these nutrients to nurture methylation can be found in liver, beef, pork, fish & eggs. Include these items in your diet regularly.

nutrients important in the methylation process
eating to nurture methylation

Vitamin B12: Found almost exclusively in animal products, the amounts listed below are sufficient for achieving the RDA:

  • 4g liver

  • 8g oysters and clams

  • 25g brain

  • 9g kidney

  • 28g heart

  • 42g spleen

  • 63g tongue

  • 12 oz cheese

  • 17.5 oz milk

You can only absorb enough of B12 every 4-5 hours to last you a day, so it is best to spread amount between meals.

important of vitamin b12 in methylation
eating to nurture methylation - vitamin b12

Without stressing about hitting these amounts perfectly, instead, aim to increase the amount of each nutrient to nurture methylation.

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