Does Collagen Count as Protein? What Builds Muscle After 40

No, collagen doesn't count toward your muscle-building protein. In older women, whey protein raised muscle building and collagen didn't, because collagen is low in leucine and missing an essential amino acid entirely.

Keep your collagen if you like it for hair, skin or joints. Just stop counting it as protein.

I see this ALL the time. Women who are "doing everything right", collagen in the coffee, a protein bar at 3 pm, a handful of almonds, and still no muscle and still the fluffy midsection. You already know how much protein you need (if not, read [How Much Protein After 40](/blog/how-much-protein-after-40)). This post is about the other half: what actually COUNTS, and how you eat it.

Why doesn't collagen build muscle?

Because muscle building has a switch, and collagen can't flip it.

The switch is leucine, an amino acid. In a study from Stuart Phillips' lab, older women took either whey or collagen peptides. Whey raised muscle building at rest and after exercise, over hours and over 6 days. Collagen didn't raise longer-term muscle building above baseline.

Collagen is low in leucine and missing tryptophan altogether. So it's not a complete protein. It's a supplement for other things.

What counts: meat, fish, eggs, dairy, tofu and whey. What doesn't: collagen.

How much protein do I need per meal after 40?

30 to 40 g at each meal. And this matters MORE as you get older, not less.

Older muscle needs a bigger dose at once to switch on. In one study, muscle building topped out at about 0.40 g per kg per meal in older men, compared with 0.24 g per kg in young men. Older muscle also responded less to small doses.

The leucine math: older adults need roughly 2.5 to 3 g of leucine per meal, which is about 30 to 35 g of high-quality protein.

And here's the one I love. In postmenopausal women eating about 800 calories a day (yes, dieting hard), 35 g of whey after lifting gave a maximal muscle-building response. More than 15 g did. The same as 60 g. So 35 g is enough, even in a deficit.

That's why the little yogurt cup and the "protein" cookie are not protein meals. They're decoration.

Why do protein meals beat grazing?

Muscle building switches on for a few hours after a proper dose of protein, then switches off and needs a break. Grazing never delivers a full dose. And it keeps insulin up all day, which in perimenopause is the LAST thing you want.

So the rhythm is four protein meals, 30 to 40 g each, nothing in between. A shake counts as a meal if it reaches 30 g. I get into timing, breakfast and the evening cut-off in [When to Eat](/blog/how-many-meals-a-day-protein-timing).

My perimenopause people: if you're genuinely hungry between meals, plan it. Make it a deliberate fourth, smaller meal (Swedes call it mellanmål). Sit down, protein first, eat it on purpose. Not a handful of something on the way past the pantry.

Can plant protein build muscle?

Yes. With the right amount and the right mix.

Here's the leucine content of common proteins:

• Whey: about 11%
• Casein: 8%
• Brown rice: 7.4%
• Pea: 7.2%
• Egg: 7%
• Soy: 6.9%
• Hemp: 5.1%

Plant proteins in whole foods are absorbed less well than animal proteins, and isolates close the gap. What helps:

• Bigger servings. In older men, 60 g of wheat protein worked where 35 g didn't.
• Blends. Soy or pea with rice or corn.
• Isolates. A pea or soy isolate does a lot of the heavy lifting.

And the good news: with protein matched, vegan and omnivore diets built similar muscle and strength. So vegetarian is not an excuse. Lean on tofu, tempeh, soy milk, legumes, eggs and dairy if you eat them, and aim for the top end of every serving.

How do I know if a food is actually high in protein?

Use the "add a zero" rule. Five seconds, no app.

Add a zero to the protein grams on the label. If that number is equal to or higher than the calories, it's a protein-first food.

• 20 g protein, 180 calories: 200 vs 180. Passes.
• 8 g protein, 210 calories: 80 vs 210. Doesn't. That's not your protein source, no matter what the front of the package screams.

Protein powders are food, by the way. A shake is an easy way to hit 30 g at a meal. Pick a product that's third-party tested for contaminants and check the protein per scoop.

Should I eat less protein when I'm losing fat?

The opposite. Protein is what keeps your muscle while the fat comes off.

In a big calorie deficit with hard lifting and intervals, people eating 2.4 g per kg a day gained 1.2 kg of lean mass and lost 4.8 kg of fat. On 1.2 g per kg, they gained 0.1 kg lean and lost 3.5 kg of fat. Honest caveat: that study was in young men. But the direction is clear, and it's why our fat-loss phase has the highest protein default.

You want to get older AND better, not just smaller. Smaller and weaker is not the goal. Harder to kill beats easier to manage, every time.

Is a high-protein diet bad for my kidneys?

Not if your kidneys are healthy. Across 28 studies with over 1,300 people, including people with obesity, type 2 diabetes or high blood pressure, higher-protein diets did not harm kidney function in people without kidney disease.

This isn't medical advice. If you have diagnosed kidney disease or reduced kidney function, talk to your doctor before following a high-protein target.

What to do this week

• Drop collagen from your protein count. Keep it if you like it.
• Run your three most-eaten "protein" foods through the add-a-zero rule. Be ruthless.
• Build four meals around 30 to 40 g each: eggs and Greek yogurt, chicken, fish, tofu, a 30 g shake.
• Stop grazing. When you're two weeks in, you'll notice you're less hungry, not more.

Quick answers

Does collagen count as protein? Not toward your muscle target. In older women, whey built muscle and collagen didn't. Keep it for hair, skin or joints if you like it.

Can my body only absorb 30 g of protein at once? It absorbs all of it. About 30 to 40 g maximises the muscle-building signal at one meal, which is why protein is spread over four meals.

Do women need less protein than men? No. Per pound of goal weight the target is the same, and older muscle needs a larger dose per meal.

Can I build muscle on plant protein? Yes, with enough total protein, bigger servings and smart mixing. With protein matched, vegan and omnivore diets built similar muscle and strength.

How do I know if a food is high in protein? Add a zero to the protein grams. If that's equal to or more than the calories, it's a protein-first food.

Sources. Oikawa SY, et al. Whey protein but not collagen peptides stimulate acute and longer-term muscle protein synthesis in healthy older women. American Journal of Clinical Nutrition. 2020. Moore DR, et al. Protein ingestion to stimulate myofibrillar protein synthesis requires greater relative protein intakes in healthy older versus younger men. Journals of Gerontology Series A. 2015. Layman DK. Impacts of protein quantity and distribution on body composition. Frontiers in Nutrition. 2024. Larsen MS, et al. Dose-response of myofibrillar protein synthesis to ingested whey protein during energy restriction in overweight postmenopausal women. Journal of Nutrition. 2023. van Loon LJC. Plant versus animal-based proteins to support muscle conditioning. Gatorade Sports Science Institute, Sports Science Exchange #220. 2021 (citing Gorissen 2016, Hevia-Larraín 2021). Longland TM, et al. Higher compared with lower dietary protein during an energy deficit combined with intense exercise. American Journal of Clinical Nutrition. 2016. Devries MC, et al. Changes in kidney function do not differ between healthy adults consuming higher- compared with lower- or normal-protein diets. Journal of Nutrition. 2018.