Collagen Supplements: What They Can and Can't Do for Your Muscles

Collagen supplements have exploded in popularity, with claims ranging from better skin to improved joint health to enhanced muscle building. But not all protein is created equal, and what works for one goal may not work for another.

When it comes to building and maintaining muscle, collagen has significant limitations you should understand.

The Incomplete Protein Problem

Collagen is an incomplete protein. It lacks essential amino acids—particularly tryptophan and methionine—that your body needs for muscle protein synthesis. Unlike whey, casein, or even soy, collagen doesn't provide the full amino acid profile required for optimal muscle building.

Research has consistently shown that collagen underperforms compared to complete proteins for muscle-related goals. One meta-analysis concluded that collagen is "inferior to high-quality proteins like whey for supporting resistance training adaptations."

This doesn't mean collagen is worthless. It may have benefits for skin, joints, and connective tissue. But if your primary goal is building or maintaining muscle, collagen shouldn't be your protein of choice.

The Marketing vs. The Science

Some studies appear to show collagen supporting muscle growth. But look closer at the research design.

A recent study found that a whey-collagen blend increased muscle protein synthesis. Sounds promising—until you realize the comparison wasn't between whey alone and whey plus collagen. It was between the blend and water.

When you compare a protein-containing supplement to nothing, of course the protein wins. But that doesn't tell you anything about whether collagen itself contributes to the effect. The whey in the blend likely drove the results.

This is a common pattern in supplement research. Studies that compare a supplement to a placebo (nothing) show benefits. Studies that compare the supplement to an established alternative often show the new option is no better—or worse.

What Actually Builds Muscle

For muscle protein synthesis and resistance training adaptations, you need:

Complete protein with all essential amino acids. Your body can't synthesize muscle tissue without the full set of building blocks.

Adequate leucine. This amino acid is particularly important for triggering muscle protein synthesis. Whey protein is especially high in leucine. Collagen is low.

Sufficient total protein. Most research suggests 1.6-2.2 grams per kilogram of body weight for those actively training.

Resistance training stimulus. Protein alone doesn't build muscle. It supports the adaptation to training stress.

Complete protein sources that support muscle building include:

• Whey and casein (dairy-based)
• Egg protein
• Soy protein
• Pea protein (when combined with other plant sources)
• Meat, fish, and poultry
• Greek yogurt and cottage cheese

Where Collagen Might Help

While collagen isn't ideal for muscle, it may have legitimate uses:

Joint and connective tissue health. Some research suggests collagen peptides may support joint function and reduce joint pain in athletes. The evidence is modest but promising.

Skin health. Studies have found improvements in skin elasticity and hydration with collagen supplementation.

Tendon and ligament support. Collagen is a major component of connective tissue, and supplementation may support tissue repair.

If you're dealing with joint issues or prioritize skin health, collagen might be worth considering. But don't expect it to replace your post-workout protein shake.

Practical Recommendations

If your goal is muscle building: Prioritize complete proteins. Whey, casein, eggs, and quality plant blends should be your primary protein sources. Don't count collagen toward your daily protein target for muscle-building purposes.

If your goal is joint health: Consider adding 10-15 grams of collagen peptides daily, separate from your muscle-focused protein intake. Take it with vitamin C, which supports collagen synthesis.

If budget is limited: Skip collagen and invest in a quality complete protein source. You'll get more muscle-building benefit per dollar.

Don't be fooled by marketing. When a study shows a supplement "works," always ask: compared to what? A supplement that beats a placebo but loses to established options isn't necessarily worth your money.

The Bottom Line

Collagen supplements have their place, but muscle building isn't it. Collagen is an incomplete protein that lacks essential amino acids needed for optimal muscle protein synthesis. Research consistently shows it underperforms compared to complete proteins like whey.

If you want to build or maintain muscle, prioritize complete protein sources. If you're interested in collagen for joint or skin benefits, consider it as an addition to—not a replacement for—your muscle-building nutrition strategy.

Use the AFT Calculator to track your strength gains, and remember that quality protein intake is essential for performance on events like the MDL and HRP.