Do Collagen Supplements Work for Skin Aging?

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I assumed that collagen proteins would get completely broken down in the digestive tract, but I was wrong.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Collagen supplements have become quite the trendy treatment for aging skin, available in an array of pills, powders, and products, from bars and gummies to collagen coffee and beer. Social media is said to be “inundated with paid ads marketing unsubstantiated claims.” What claims, if any, can be substantiated?

The word collagen comes from the Greek kola, meaning “gum,” and gen, meaning “producing.” Its gelling nature is exemplified by Jell-O gelatin (which is basically just cooked collagen).

It is our most abundant protein, and the main structural component of most of the tissues in our body. For example, up to three quarters of our skin by weight may be pure collagen. There are actually dozens of different types, but they all share a characteristic triple helix configuration of coiled subunits. What happens when we eat it?

If someone would have asked for my educated guess about taking collagen before I took a deep dive for my book How Not to Age, I would have dismissed it as witch-doctory woo-woo. Eating skin for your face would seem to make as much sense as eating brains to make yourself smarter, or eyeballs to improve your vision. After all, when you eat proteins, they are broken down into their constituent amino acids, which are then rebuilt into any protein your body needs. And, of all proteins to eat, collagen is the only protein in our food supply that’s truly incomplete. That is, it’s missing an essential amino acid.

Other dietary proteins, including all plant proteins, contain all of the essential amino acids—in fact, that’s why they’re called essential, since animals like us can’t make them. Collagen, though, is missing the amino acid tryptophan. So, the only protein source that you couldn’t live on is Jell-O, since it effectively has a protein quality score of zero. But obviously that’s not all people eat; so, significant amounts of collagen could be incorporated into the diet without keeling over. But tryptophan is special. Randomizing people to even a single meal of a gelatin-based protein drink can lead to memory impairments within hours, due to “acute tryptophan depletion” (presumably due to a drop in the brain of serotonin, which is made from tryptophan, and doesn’t just regulate mood, but learning and memory as well). So, the idea of collagen supplements never made sense to me. But the proof is in the pudding (or rather, perhaps, the Jell-O). What, does the science say?

My assumption that collagen proteins would get completely broken down in the digestive tract was wrong. Feed people gelatin from pig skin or chicken feet, and little pieces of collagen particles can be found floating in their bloodstream within hours. Though no further tracking has been done in humans, in rodents, collagen fragments from gelatin consumption can end up in cartilage and skin. Now, biologically, there is no mechanism by which these fragments could be directly incorporated into new collagen, but there may be an indirect way collagen bits could boost collagen deposition––as appears to happen in rat skin. What about in people?

Some of the collagen studies lack control groups. I’m reminded of that vintage Star Trek episode Mudd’s Women, where Kirk successfully swaps out a youth-giving supplement for a placebo without the aliens noticing. Randomized controlled trials are scarce, but a systematic review and meta-analysis of the available data showed that, although outcomes were mixed, on average, there were beneficial effects for skin hydration, elasticity, and roughness. Despite some favorable results, much of the dermatology community has remained skeptical, suggesting the collagen supplement industry may just be flooding the zone with poor quality, biased studies.

The studies are often funded by collagen supplement manufacturers, and the overall quality of evidence is considered to be “limited, contradictory,” “not particularly robust… .” A 2022 review entitled “Myths and media in oral collagen supplementation for the skin, nails, and hair” in the Journal of Cosmetic Dermatology concluded that “Dermatologists should be aware of the unsubstantiated proclamations of collagen made by companies [which] surpass any evidence currently supported by the literature.” And, given the insufficient evidence, “collagen cannot be routinely recommended at this time.” Moreover, the evidence is considered to be “particularly unconvincing” when compared to methods more definitely shown to have a positive effect on skin collagen, such as sunscreen use, smoking cessation, and a healthy diet.

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Collagen supplements have become quite the trendy treatment for aging skin, available in an array of pills, powders, and products, from bars and gummies to collagen coffee and beer. Social media is said to be “inundated with paid ads marketing unsubstantiated claims.” What claims, if any, can be substantiated?

The word collagen comes from the Greek kola, meaning “gum,” and gen, meaning “producing.” Its gelling nature is exemplified by Jell-O gelatin (which is basically just cooked collagen).

It is our most abundant protein, and the main structural component of most of the tissues in our body. For example, up to three quarters of our skin by weight may be pure collagen. There are actually dozens of different types, but they all share a characteristic triple helix configuration of coiled subunits. What happens when we eat it?

If someone would have asked for my educated guess about taking collagen before I took a deep dive for my book How Not to Age, I would have dismissed it as witch-doctory woo-woo. Eating skin for your face would seem to make as much sense as eating brains to make yourself smarter, or eyeballs to improve your vision. After all, when you eat proteins, they are broken down into their constituent amino acids, which are then rebuilt into any protein your body needs. And, of all proteins to eat, collagen is the only protein in our food supply that’s truly incomplete. That is, it’s missing an essential amino acid.

Other dietary proteins, including all plant proteins, contain all of the essential amino acids—in fact, that’s why they’re called essential, since animals like us can’t make them. Collagen, though, is missing the amino acid tryptophan. So, the only protein source that you couldn’t live on is Jell-O, since it effectively has a protein quality score of zero. But obviously that’s not all people eat; so, significant amounts of collagen could be incorporated into the diet without keeling over. But tryptophan is special. Randomizing people to even a single meal of a gelatin-based protein drink can lead to memory impairments within hours, due to “acute tryptophan depletion” (presumably due to a drop in the brain of serotonin, which is made from tryptophan, and doesn’t just regulate mood, but learning and memory as well). So, the idea of collagen supplements never made sense to me. But the proof is in the pudding (or rather, perhaps, the Jell-O). What, does the science say?

My assumption that collagen proteins would get completely broken down in the digestive tract was wrong. Feed people gelatin from pig skin or chicken feet, and little pieces of collagen particles can be found floating in their bloodstream within hours. Though no further tracking has been done in humans, in rodents, collagen fragments from gelatin consumption can end up in cartilage and skin. Now, biologically, there is no mechanism by which these fragments could be directly incorporated into new collagen, but there may be an indirect way collagen bits could boost collagen deposition––as appears to happen in rat skin. What about in people?

Some of the collagen studies lack control groups. I’m reminded of that vintage Star Trek episode Mudd’s Women, where Kirk successfully swaps out a youth-giving supplement for a placebo without the aliens noticing. Randomized controlled trials are scarce, but a systematic review and meta-analysis of the available data showed that, although outcomes were mixed, on average, there were beneficial effects for skin hydration, elasticity, and roughness. Despite some favorable results, much of the dermatology community has remained skeptical, suggesting the collagen supplement industry may just be flooding the zone with poor quality, biased studies.

The studies are often funded by collagen supplement manufacturers, and the overall quality of evidence is considered to be “limited, contradictory,” “not particularly robust… .” A 2022 review entitled “Myths and media in oral collagen supplementation for the skin, nails, and hair” in the Journal of Cosmetic Dermatology concluded that “Dermatologists should be aware of the unsubstantiated proclamations of collagen made by companies [which] surpass any evidence currently supported by the literature.” And, given the insufficient evidence, “collagen cannot be routinely recommended at this time.” Moreover, the evidence is considered to be “particularly unconvincing” when compared to methods more definitely shown to have a positive effect on skin collagen, such as sunscreen use, smoking cessation, and a healthy diet.

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Doctor's Note

This is the first in a three-video series on collagen. Collagen Supplements for Arthritis and How to Boost Collagen Synthesis with Diet are coming up.

My new book, How Not to Age, is all about aging, and you can pick up a copy now from your local public library or wherever books are sold. If you haven’t seen them yet, check out the book trailer and my new presentation. (As always, all proceeds I receive from all of my books are donated to charity.)

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