Scientists look at what works, what doesn't, and what to watch out for
I was recently invited to contribute to a Vogue magazine article exploring the rise of collagen supplements. Collagen has become one of the most talked-about ingredients in wellness—showing up in beauty products, shakes, and your coworker’s morning coffee. The pitch? That it can improve skin elasticity, strengthen joints, reduce wrinkles, and accelerate recovery. And while some of those claims outpace current science, one thing is clear: collagen plays a vital role in the health of our connective tissue. What’s less clear is whether supplementing with it delivers the benefits people expect—and if it does, how to use it effectively.
That’s what makes a new study published in Medicine & Science in Sports & Exercise so interesting. Rather than simply asking whether collagen “works,” researchers explored how it interacts with the body’s complex protein synthesis systems, particularly in connective tissue and muscle. They tested a combined approach: pairing collagen peptides with whey protein to examine whether the synergy could stimulate tissue repair. Previous published studies from the same team showed no effects from taking collagen on its own paired with exercise, even at high doses, making the potential synergy with a high-quality protein compelling.
For anyone focused on recovery, healing from injury, or healthy aging, that question matters. If we’re going to supplement with collagen, we should understand the best way to do it—and as this study shows, there may be more to it than tossing a scoop into your almond milk latte.
Source Matters—Skin vs. Bone
If you’re thinking about collagen supplementation, the first thing to get right is quality—and that starts with the source. What you want is collagen derived from skin, such as fish skin or bovine hide. That’s where the highest-quality supplements come from. Here’s where the “ugly” part comes in: many products use collagen from bones or animal byproducts, usually seen in bone broth or collagen peptides from bovine sources. You can check the front and back labels carefully. While these sources technically provide glycine and proline—two amino acids important for collagen synthesis—they can also carry unwanted baggage. Bones are where heavy metals like lead tend to accumulate. That’s especially relevant for long-term health. So although bone broth is trendy, it’s not necessarily clean. Skin-derived collagen is typically a safer, purer option. It's a critical consideration—especially if you’re taking collagen daily. Prioritize sourcing from fish or bovine skin, and you’ll reduce the risk of contaminant exposure.
And don’t get too caught up in whether a product is labeled “type I” or “type III.” That detail doesn’t matter as much as people think. We’re not absorbing whole collagen molecules and inserting them into our tendons. The body breaks collagen down into amino acids—mainly glycine and proline—and those serve as raw materials for rebuilding connective tissue. That’s the real basis of any collagen supplementation.
Why Collagen Alone Falls Short—and How Whey Changes the Game
After a workout, the body’s demand for amino acids spikes—especially the ones used in tissue repair. Interestingly, even after consuming whey or milk protein, glycine levels in the bloodstream can dip. Why? Probably because the body is trying to synthesize more connective tissue than it has glycine available to support. That’s where the logic for collagen supplementation steps in, delivering extra glycine and proline to help keep up with the demand.
But collagen alone isn’t a complete protein. It lacks essential amino acids like leucine, which are key drivers of muscle protein synthesis via the mTOR signaling pathway. That’s a problem if you’re relying solely on collagen for recovery or rebuilding. The study addressed this by pairing 25 grams of whey protein with 5 grams of collagen peptides in a randomized, controlled trial. Researchers enrolled 28 healthy, recreationally active men, who performed single-leg resistance exercises. Afterward, participants received either the protein blend or a placebo. Muscle biopsies allowed researchers to directly measure both myofibrillar protein synthesis (which repairs muscle fibers) and connective tissue protein synthesis in muscle.
The results were telling: the group that consumed the whey-collagen blend saw significantly greater myofibrillar protein synthesis compared to placebo—in both trained and untrained legs. Even more interesting, increases in connective tissue synthesis were most prominent in the untrained leg. This suggests that collagen’s benefit may be more pronounced in recovery states, where tissues aren’t under immediate load.
Why does this matter? It reinforces the idea that collagen supplements on their own may not be enough. They help provide building blocks for connective tissue, but without the full amino acid profile needed for muscle repair. Combining collagen with a complete protein—like whey—creates a smarter rebuilding plan. One that supports both muscle fibers and connective tissues.
(Photo: Medicine & Science in Sports & Exercise)
Timing, Movement, and Nutrient Delivery
Most people think of nutrient timing in terms of bloodstream availability. But for connective tissue, it’s more complicated. Tissues like tendons, ligaments, and cartilage have poor blood supply. That means they rely less on circulation and more on mechanical loading to receive nutrients. Here’s how it works: when connective tissue is loaded—say, during a squat or rehab exercise—it gets compressed, squeezing fluid out. When the tissue unloads, it draws fluid (and nutrients) back in from the surrounding environment. Think of it like a sponge: squeeze it under load, and it pushes fluid out. Release the pressure, and it soaks up what’s available. That’s when glycine, proline, and other nutrients can be absorbed into the tissue matrix.
So, when you take collagen matters. Consuming it close to movement—either before or after—might be key. That ensures your tissues are primed to absorb the nutrients when loading and unloading cycles happen. Also, don’t skip vitamin C. It’s a cofactor for enzymes that assemble collagen’s triple helix structure—without it, the synthesis process stalls. Whether it’s from food or a supplement, make sure your vitamin C status is sufficient if you take collagen. In heavy training blocks or rehab settings, this timing may become important. You’re not just aiming for nutrient intake—you’re targeting nutrient delivery, where it’s needed most.
Practical Recommendations for Collagen Use
If you’re active, aging, or recovering from injury, this study offers some practical insight. Collagen alone may not be sufficient for recovery or adaptation. Yes, it provides glycine and proline—potentially useful for tendons and ligaments—but it lacks the full spectrum of amino acids required for full recovery, especially in muscle tissue. That’s where the collagen + whey strategy makes sense. The 25:5 gram ratio used in the study reflects more of a recovery and synthesis drink than a beauty supplement. It’s designed to support structure, not just appearance. And in that context, it seems to work: both connective and muscle tissues receive the raw materials they need to repair and adapt. It also underscores that collagen isn’t just for skin and nails. Used strategically, it’s a tool for synthesis, repair, and recovery—especially when integrated into a broader protein plan that accounts for timing, movement, and quality.
- Pair it with a complete protein like whey to support both muscle and connective tissue. The 25:5 g ratio used in studies is a strong template.
- Time your intake pre- or post-exercise, ideally within an hour, to coincide with tissue loading and recovery windows.
- Choose hydrolyzed collagen peptides for better absorption and quicker bioavailability.
- Include vitamin C, either through food or a supplement, to activate the enzymes responsible for collagen synthesis.
- Select skin-derived collagen (from fish or bovine sources) to minimize exposure to heavy metals often found in bone-sourced products.
Collagen isn’t a miracle powder—but used correctly, it may be a useful recovery and resynthesis tool. For athletes, older adults, or anyone dealing with nagging issues needing repair, it can could support the structural integrity of your connective tissues when paired with complete protein and thoughtful timing. While many claims about collagen still outpace the science, this study gives us a high-quality glimpse into how collagen—when used thoughtfully—can play a role in recovery and connective tissue support.