HomeHEALTH & WELLNESSShould You Supplement With Glycine Or Collagen?

Should You Supplement With Glycine Or Collagen?

In my book Paléo Nutrition, published in 2014, I explain why collagen can provide many health benefits. But I also explain why it is interesting to choose Glycine instead of the latter. So which one to choose and why?

Why Supplement With Collagen?

For millions of years, when humans ate animal products, they did not just eat muscle as we do today ( beef filet, fish, chicken, etc.). It also consumed organs such as the liver or brain (excellent sources of vitamins and essential fatty acids when antibiotics and pesticides do not contaminate animals) and connective tissues (skin, bone marrow, cartilage, etc.). However, it turns out that all these connective tissues are very rich in collagen, a protein. 

Collagen has a concentration of % Glycine, an amino acid, of 30%, while meat or fish proteins contain only 4% glycine. Today, our only source of collagen is gelatin, which is used in cooking or confectionery in small quantities. Therefore, we can ask ourselves: are we deficient in Glycine? In December 2009, Spanish researchers with expertise in biochemistry and metabolism calculated very precisely how much Glycine our body obtains and how much it uses. For contributions, there are:

  1. Food intake is 1.5 to 3 g per day (up to 6 g with a diet very, very rich in proteins)
  2. The synthesis of Glycine in our body from L-serine, an amino acid provided by food or recycled in our body, provides approximately 3 g of Glycine per day.

And for needs, there is:

  1. the synthesis of glycine-based metabolites requires 1.5 g of Glycine per day
  2. synthesis of other minor proteins requires 1 gr per day
  3. the synthesis of collagen in our body requires 12 grams per day, at least


If we want to meet our Glycine needs, ideally, we are in a constant deficit of 10 grams daily. This deficit also significantly impacts our total life expectancy; as my previous article explains, “Science reveals the secret of longevity.” Following this discovery, researchers considered that Glycine should have the status of a semi-essential amino acid that can be produced in the body but whose requirements are too high for this synthesis alone to be sufficient. 

They add: “to cover all metabolic needs and collagen synthesis, approximately 10 g of additional Glycine are necessary each day for a 70 kg adult. Supplementation is necessary to ensure healthy and optimal metabolism.” This may seem curious at first glance, but it becomes utterly logical in the context of evolution: Paleo man consumed enough collagen to cover his Glycine needs. At the same time, this is no longer the case for us. But what can we expect and observe from daily glycine supplementation? Studies are multiplying on the subject.

The Benefits Of Glycine Supplementation

Here is the list of benefits observed (at the time of writing) when you supplement with a sufficient dose of Glycine:

  1. At a dose of 3 g at bedtime, Glycine improves sleep quality by accelerating the onset of the slow-wave sleep phase (“restorative sleep”). When the same dose of Glycine is given to individuals with a sleep deficit (sleep time reduced by 25%), there is a significant reduction in fatigue during the following day compared to the placebo. In addition, Glycine improves concentration, responsiveness, and memory when previously deprived of sleep. These effects could result from the stimulation of growth hormones by glycineGlycine in humans.
  2. Because of this effect on growth hormone, Glycine may accelerate the loss of body fat if taken as part of a low-calorie (slimming) diet.
  3. It accelerates muscle mass gains in athletes because the muscles comprise a lot of collagen. In a study on older adults, gains were accelerated dizzyingly: + 50%.
  4. Preliminary experiments suggest that Glycine could improve insulin sensitivity and reduce abdominal fat storage. In cases of metabolic syndrome (pre-diabetes), benefits are observed on the health of blood vessels, with a reduction in blood pressure.
  5. Since Glycine allows the synthesis of collagen, it is an effective anti-aging agent that delays the appearance of wrinkles and contributes to strong bones, joints, and supple arteries. Supplementation in older adults (60 – 75 years old) has shown the ability to completely restore glutathione levels, a powerful antioxidant that allows adaptation to stress, to those of young adults. Unlike classic antioxidants taken orally, which can have harmful effects (see the various articles on my blog), this increase in endogenous glutathione production occurs naturally and is entirely beneficial.
  6. Glycine often improves muscle strength because it increases our production of creatine, which limits its synthesis in our body.

Collagen Or Glycine?

The benefits of Glycine are clear, but do you get the same effects when you supplement with collagen? The answer is obviously yes because collagen provides a lot of Glycine. But it also provides another amino acid not found in large quantities in food: hydroxyproline. Hydroxyproline is used in our body to make collagen, along with Glycine. This is the only advantage of collagen over Glycine in composition. 

Here is the approximate content of the different amino acids in collagen (the figures vary slightly depending on whether we consider porcine, ovine, or bovine collagen). or sailor): Thanks to the additional presence of hydroxylysine, collagen is theoretically more interesting than Glycine in the event of problems linked to connective tissues: tendinitis, joint injury, and healing. But be careful because there is another parameter to take into account…

Indeed, collagen, sold commercially as “collagen peptides,” or “collagen” for short, is made from leftovers from the meat industry. These are, therefore, the cheapest remains from the slaughter of animals from industrial farms. Collagen is, consequently, one of the worst representatives of today’s problems regarding animal exploitation and the rampant industrialization of animals.

In addition, since it is an inexpensive waste, it is obviously on the front line in case of a health problem such as those we have already experienced (prison, mad cow, etc.). Added to this is that no traceability for these products is possible since they come from leftovers from different slaughterhouses… Finally, as collagen becomes fashionable, it is often sold quite expensive considering it is… Conversely, Glycine does not present any of these problems:

  1. It is produced by bacterial fermentation or synthesis,e.
  2. There is no animal exploitation.
  3. Traceability is at its maximum.

In addition, the Glycine obtained in this way is 100% pure, without risk of contamination. Finally, it is much cheaper. On the other hand, the way to take Glycine differs from the way to take collagen.

How Do You Take Glycine As A Food Supplement?

It was long thought that taking Glycine at any time was impossible. Indeed, Glycine is a glucose-forming amino acid, meaning that if we eat it when our blood sugar is very low, it will be partially transformed into sugar by our liver to maintain blood sugar levels. This does not happen with collagen because Glycine is bound to other amino acids.

However, there are other glucose-forming amino acids, and their role in the production of blood sugar remains minimal compared to our glucose reserves (which are essential). Studies have also shown that taking Glycine as a dietary supplement does not increase blood sugar and that people with diabetes can use it. Glycine can, therefore, be taken at any time, even if it is often taken during a meal, for convenience, like collagen.

The recommended dose of Glycine is between 6 and 15 g, depending on its size and diet, to be diluted in a glass of water. You can do without glycine or collagen supplementation if your diet provides enough. The easiest way to get it through food is to consume bone broth. To make them, nothing could be simpler than buying as many animal products as possible (for example, a whole chicken rather than a chicken filet).

Once the meat is consumed, place the entire carcass and remains in a large pot and cook over low heat, covered, for a few hours. Optionally add carrots, onions, and herbs to the preparation to flavor it. After cooking, filter through a strainer. What you get back is collagen. You can freeze and reuse it as a cooking base for simmering or making soups. However, unless you eat it daily, this will always be a little low, and it is recommended to supplement with Glycine, given our modern diet.

Comparison Of The Best Glycine Powder Food Supplements

As a dietary supplement, Glycine can come from synthesis and animal extraction. Most brands use synthetic versions without animal products, but asking the seller for confirmation is recommended. Non-animal Glycine can be found in Nutrixeal or Nutrimuscle, for example. I recommend French brands that comply with French health safety rules (guarantee of quality) and offer a powder product without additives.

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