Korean Collagen: Why Dermatologists Take It With Vitamin C

I'm Dr. Hongseok Kim, a board-certified dermatologist with 21 years of practice and the medical director of VOS Dermatology Clinic in Gangnam, Seoul, right in front of Dosan Park. At VOS I see every patient myself, from the first consultation to the last treatment.

Korean collagen drinks, jellies and powders are one of the things visitors most often ask me about, usually with the same question: does drinking collagen actually do anything for my skin? Dermatologists do not all agree, so I sat down with two fellow dermatologists who also run YouTube channels, and we argued it out. This page is based on that YouTube video from November 2024; it summarizes what I explained there for readers abroad, without product brand names. The video above can be watched with translated captions.

What collagen is, and what it does in your skin

Short answer: collagen is a structural protein that holds the skin's framework together.

The word collagen comes from the Greek for glue (in the video at 00:49). It is a protein found throughout the body, including the skin, and its fibres are tightly wound together, like an adhesive that sets hard. Gelatin comes from it too. Of the twenty or so amino acids, collagen is built mainly from glycine, hydroxylysine and hydroxyproline; these form chains, and three chains twist together into what is called a triple helix. In the dermis, this structure plays a central role, which is why collagen has become the hot topic in anti-ageing.

Collagen is structure, not stretch

Short answer: collagen gives firmness and support, while elastin gives skin its stretch and bounce.

When people talk about collagen, they usually talk about elasticity, and that is slightly off (in the video at 02:10). We compared collagen to a twisted rope. It is very strong, its fibres bundle together, and it holds a structure that resists force. But a rope does not stretch like a rubber band. Think of jeans: plain denim is collagen alone; stretch denim, with spandex, is collagen plus elastin. In Korean the terms make this clear: collagen is the "glue fibre" that gives firmness, elastin is the "elastic fibre".

So when collagen drops, the support weakens: volume falls and wrinkles form. When skin loses its snap-back and feels slack, that is more about elastin and other changes than about collagen alone.

Why Korean collagen products focus on collagen, not elastin

Short answer: collagen is by far the larger component and its loss is easy to see; restoring elastin's function is much harder.

By dry weight, collagen makes up 70% or more of the dermis, while elastin is around 1.5 to 4.8% (in the video at 04:58). Losing a large share of something abundant is noticed far more than losing some of something small. With sun damage, collagen quantity drops, while elastin fibres degenerate: they may still be there, but they behave like worn-out rubber bands.

That is why so many cosmetics, supplements and medical devices are built around collagen, and why nobody offers "elastin injections" (in the video at 06:01). Supplying quantity is the most direct approach and shows the clearest effect. Restoring a function that has broken down is much harder and would need precise control at the genetic level that we do not yet have.

What to take with collagen: vitamin C and essential amino acids

Short answer: if you take collagen, take vitamin C as well, and make sure you get essential amino acids.

Amino acids are either non-essential, which the body can make, or essential, which must come from food (in the video at 07:17). For collagen to form properly, lysine needs a hydroxyl group attached to become hydroxylysine, and that reaction needs vitamin C (in the video at 08:27). Once that happens, collagen is assembled and released outside the cell. In other words, you may take in collagen, but without vitamin C the process does not run smoothly. That is why the advice in the video is simple: if you are going to take collagen, take vitamin C.

I also recommend products that contain essential amino acids. In published studies, when these amino acids were labelled and tracked, they went to the joints and partly to the skin, and some people with joint pain reported less pain after taking them (in the video at 09:04). That suggests what you take does have an effect in the body, although it is not a promise for every person. The real question is whether enough reaches the skin to prevent wrinkles, since the body has many other organs that need collagen. I am sceptical of claims that wrinkles will disappear, but I still tell people that steady, long-term intake is likely to do some good.

The debate: is oral collagen worth it?

Short answer: our honest verdict was "not useless, but not worth staking everything on".

One of my colleagues took the critical side (in the video at 10:21). He agreed with my point, but argued that the studies behind oral collagen are not of high quality, and that even if it works, it is inefficient. His comparison: imagine getting hold of a leaked exam paper, but it reaches your child shredded into pieces. Taping it back together might get you a few answers, but it is a very inefficient way to pass. If you take it hoping your skin will improve, you may be disappointed.

The market is huge because not everyone can visit a clinic; people want something they can do at home, and taking a supplement is the easiest choice. We summed it up as: not nothing, but not something to stake everything on (in the video at 12:08). Medicine also changes. When I was a student, the idea that milk or chocolate caused acne was called a myth; now textbooks say they can have an influence. We will have to see. Whether collagen in a cream or hydrolyzed collagen can reach the dermis, and how to protect the collagen you already have, I cover in my other video on collagen for skin.

Collagen works better with a signal to rebuild

Short answer: taking collagen alone is like taking protein without exercise; paired with treatment, it has a better chance of going to the skin.

The point we landed on is easy to remember (in the video at 12:52). People who train hard take protein to build muscle. Taking only collagen is like drinking protein shakes without exercising and expecting muscle. Create the conditions first: a treatment sends the skin a signal to rebuild, and collagen taken around that time is more likely to be drawn there. For example, after RF lifting such as Thermage FLX, collagen intake may support the skin's response more than collagen on its own.

The same logic may apply to sensitive skin, where a damaged barrier and inflammation already push the skin into repair mode (in the video at 13:32). Controlled heat from a laser or RF device is a deliberate stimulus; irritation is an unwanted one, but either way the cells are trying to recover, and building blocks supplied then may help more. Even the colleague who made the shredded-exam comparison half took it back: set up the right situation to piece it together, and it can help.

So my view of Korean collagen products is balanced: take them consistently if you like, add vitamin C, and do not expect them to replace treatment. If you are planning clinic care, my notes on Korean anti-aging and Korean skin tightening treatment go further, and you can read creator experiences at VOS.

Results vary from person to person, and whether supplements, treatment or both make sense for you is decided at a consultation.

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Results, swelling and recovery vary from person to person. This page is general information from VOS Dermatology Clinic based on Dr. Kim's video and does not replace an in-person consultation.