Which Protein Powder Should You Actually Use? Whey vs Casein vs Plant vs Collagen

Whey, casein, plant, soy, collagen, beef. What’s the actual difference between all of them, and which one do you need?

This question comes up a lot and it really comes down to two main things. What’s actually in the powder, and what you’re using it for. So I’m going through all of them here, what each one is actually good for, which ones give you a complete amino acid profile and which ones fall short, and what those Roman numerals on the collagen tubs really mean.

P.S. I’ve linked several products throughout this post so you have easy access to what I personally use and recommend. Some of them are affiliate links, meaning I earn a small commission at no extra cost to you.

Which protein powder should you use?

Here’s the short version, and then I’ll go through each one.

What’s the difference between whey concentrate and whey isolate?

The biggest difference is in the speed of digestion. This comes down to the purpose and timing that you’re using the protein supplement for. A whey concentrate protein contains more carbs and fats than a whey isolate protein does. Whey isolate is also nearly void of lactose while whey concentrate typically has some lactose.

Both are whey-based, and both have complete amino acid profiles with an ideal dose of essential and branch-chain amino acids.

Whey concentrate digests a little slower than isolate does, because it still has some carbs and fat in it to slow things down. This works well as part of a meal replacement or snack throughout the day since it digests a bit slower. I like to use this when I’m making protein ice cream or baking, or even adding it to oatmeal, mug cakes, protein pancakes and waffles, or shakes. Especially for protein ice cream and baking, the consistency turns out a lot better than using the isolate.

For a concentrate, Legion Whey Concentrate is my go-to, and 1st Phorm Level-1 is a solid one too.

Whey isolate is the faster of the two, since there isn’t much carb or fat left in it to get in the way. This is a common pre or post-workout pick for that reason.

For pre-workout, we want something faster digesting so it’s not sitting in your stomach during your workout. Some people also like it first thing in the morning, since you’ve gone all night without protein. For post-workout, it gets amino acids to your muscles quickly, though you’ve got a much bigger window than people think.

For an isolate, Legion Whey+ and 1st Phorm Phormula-1 are my go-tos.

Clear whey is a newer variation. It’s processed differently so it dissolves clear instead of cloudy, which gets you something closer to a fruit drink than a thick shake. Worth a look if the creamy texture is the part you don’t love.

What is casein protein and when would you use it?

Both casein and whey are dairy-based proteins and byproducts of cheese production. They’re both complete proteins, containing all the essential amino acids and BCAAs in ideal amounts.

During cheesemaking, special enzymes or acids are added to heated milk. These cause the casein to coagulate, or change to a solid state, separating from a liquid substance. That liquid is the whey protein, which is then washed and dried into a powdered form. The remaining curds of casein can be washed and dried to create a protein powder, or added to dairy products like cottage cheese.

The main difference between whey and casein comes down to absorption rate and lactose. Casein digests slower and contains lactose, while whey, specifically whey isolate, digests faster and is typically void of lactose.

Some people like casein at night for that reason. It’s a preference more than a rule. If you want to try one, Legion Casein+ is the one I’d grab.

Is plant protein as good as whey?

Plant protein is the go-to if you’re vegan, dairy-free, or you just don’t feel great on whey. Most single plant sources are low in at least one essential amino acid though, which is why the good ones are blends instead of one plant by itself.

Pea protein is high in lysine and lower in methionine, and rice protein is the other way around, which is why you see those two paired on so many labels. Put them together and you cover all nine essentials.

The one thing plant protein doesn’t do quite as well is leucine, the amino acid that “turns on” muscle building. Whey is around 11% and pea is around 8%, so you need a slightly bigger scoop to get the same signal. When the protein is matched though, the training studies we have don’t show whey pulling ahead.

I use Legion Plant+ Cinnamon Cereal and Salted Caramel in my coffee in the morning because it tastes so good and mixes really well, and in my Creamis because I like the texture.

Is soy protein safe?

Soy is the one plant protein that’s complete on its own, so it doesn’t need to be blended with anything to cover the essentials. Edamame or tofu work well too, if you do soy.

On the whole phytoestrogen thing, isoflavones are not the same as estrogen and they don’t behave like it in your body.

And this isn’t one of those topics where the science is murky and nobody really knows. Soy has been studied a lot, including trials that specifically measured whether isoflavones produce estrogen-like effects, and they don’t. The worry has stuck around a lot longer than the evidence supports it. If you’ve been told to avoid soy for a specific reason though, that’s still a conversation for you and your doctor.

What is egg white protein good for?

Egg white protein is complete and dairy-free, and it’s a good one to rotate in to switch things up if whey isn’t sitting well with you. It mixes thin though, so don’t expect the creamy texture you get from whey.

Is collagen a complete protein?

No. Collagen is low in several essential amino acids, especially leucine and the other BCAAs that we know are important for muscle growth and repair. It’s also missing tryptophan completely, which is why it’s technically an incomplete protein.

That doesn’t make it useless. Collagen is generally rich in the amino acids glycine, arginine and proline. Unlike our ancestors who were consuming nose-to-tail animal foods, most of us are probably slightly deficient in the amino acids that come from collagen-rich foods, specifically glycine. Collagen supports our connective tissue and collagen-based structures like fascia, ligaments, tendons, cartilage, skin, hair and nails.

If you’re not consuming collagen-rich foods on the daily, meaning real bone broth, the skin and bones of fish like sardines and mackerel, chicken skin, or slow-cooked cuts like oxtail or shank, then supplementing with collagen can be beneficial to make sure you’re getting enough of those amino acids.

Active Stacks does a collagen peptide, and Legion has one now too. 1st Phorm Collagen with Dermaval has been my go-to brand for plain collagen for a long time.

Is beef protein powder actually beef?

Often, no. Collagen and a lot of beef protein powders have similar amino acid profiles, and there’s a reason for that. There’s no legal definition of “beef protein,” so hydrolyzed collagen gets sold under that name, and plenty of what you see is exactly that.

A true beef protein isolate made from muscle is a complete protein, closer to whey. Check the label. If leucine is under about 5% of the protein and glycine is over about 15%, you’re looking at collagen with a beef label on it.

A lot of beef proteins are made from beef bones, and the better companies say this right on the label. Bone means it leans collagen rather than muscle meat. Active Stacks is a good example, and I’ll say it plainly since I just gave you the test. Theirs is made from beef bones and they add extra glycine on top, so by my own rule above it’s collagen wearing a beef label. I’ve still been recommending it for making Creamis for a long time because the consistency and flavor are just outstanding compared to a lot of other powders out there. I’m using it for texture, not to hit my protein, and that’s a fine reason to buy something.

What is bone broth protein powder?

It’s basically collagen with a different name on the tub. It’s dehydrated bone broth, so what you’re getting is the collagen and gelatin that cooked out of the bones. You’re getting the same glycine and proline, but it’s missing tryptophan, so it can’t be your only protein source.

One thing on homemade bone broth. The collagen content varies a lot batch to batch depending on the bones and how long you simmer it, so it’s not a reliable way to hit a set amount of those amino acids the way a measured scoop is. Still a great food, just not something to count on for a number.

What do the collagen type numbers mean?

You’ll see Roman numerals on most collagen tubs. All they’re telling you is where that protein shows up most in your body, not necessarily where the supplement goes once you swallow it.

The numerals on a label usually describe which animal part the collagen came from rather than which type is actually in there, so a chicken bone broth product gets listed as type II because of the cartilage that cooks down with the bones, while beef bone broth is really types I and III. A tub advertising five types is usually telling you it used five sources.

• Type I is what’s in most collagen powders. It’s concentrated in skin, bone, tendons and ligaments, and the research says it may modestly improve skin hydration and elasticity. Modest is the key word though. Some people notice a difference, others don’t.
• Type II is the joint one. It sits in the cartilage on your joint surfaces and it has the most targeted joint research behind it, though that research is about pain, stiffness and how well the joint moves, and not about regrowing cartilage that’s already gone. If joints are your reason for taking it, I’d loop in your doctor on it too.
• Type III comes bundled with type I in nearly every bovine product, and there’s currently no good evidence it does anything on its own.
• Types IV, V and X show up on hair and skin labels or in research papers. None of them are worth buying on their own in my opinion.

“Collagen peptides” or “hydrolyzed collagen” means it’s been broken down into smaller pieces. It’s the scoop-in-your-coffee kind, usually type I and III. This is what most people have.

“Undenatured type II” or “UC-II” means the protein is left whole and the dose is way smaller. Different mechanism, and it’s the one with the joint research behind it. You won’t find this one in a powder though, it’s almost always in capsule form. Legion Fortify is the one I’d point you to. And same as above, I’d loop in your doctor if joints are your reason.

Big picture, the number on the front doesn’t tell you where it goes in your body. Your body breaks those peptides down into amino acids either way, so it matters a lot less than whether you’re hitting your protein overall.

Are there heavy metals in protein powder?

A 2025 report tested 160 protein powders across 70 brands and found the plant-based ones averaged about three times the lead of the whey-based ones. Organic ran higher than non-organic too.

The supplement industry group pushed back on that report. Two of their points are worth knowing. The group behind it wouldn’t hand over its methodology or its raw data when asked, and detecting a metal is not the same as detecting a level that harms you. Neither of those makes the finding wrong. It’s why I’d treat it as a reason to be choosy rather than a reason to panic.

I believe it’s more so from the plants absorbing it from contaminated soils and water, and that lead getting concentrated during extraction. I think the machinery is secondary and much less of a factor.

This is one of the reasons to make sure you’re getting your supplements from a reputable company that does third-party testing. Of the plant options, pea tested cleanest. My go-to for plant protein has always been Legion.

So which one do you buy?

Whey, casein, plant, soy, egg white, collagen and beef all have benefits, but they don’t necessarily overlap. So if you’re using protein powder to replace a protein feeding or as a pre or post-workout supplement, you have to be aware of what the powder actually contains, mainly the amino acid profile.

If you’re not a fan of whey or casein protein, another option is to supplement with EAA’s (Legion or 1st Phorm) in addition to collagen or beef.

Nothing replaces real, whole food though, so make sure that’s your priority. Protein powders are exactly what they say they are. Supplements, to supplement your daily intake and help you hit your daily protein goal if that’s something you struggle with.

Where I fit

I’m Rachel Gregory. Board Certified Nutrition Specialist, CSCS, master’s in Nutrition and Exercise Physiology, published researcher. I coach women 40+ to build muscle instead of shrinking.

The Flex Fam is a group of women 40+ going through the same things you are, and you get your training and nutrition coaching from me right alongside them. There are live coaching calls with me too. It’s $297 for the 6-week on-ramp, then $227/month with no contract, and the full picture is here.

1-on-1 coaching with me is the most personalized thing I offer. Your program is built for you and you get direct access to me every week. I keep my 1-on-1 roster deliberately small. Pricing depends on your commitment length, and I share all of the details when I respond to your application.

Quick answers

Does collagen count toward my protein for the day? Yes, log it regularly and count it toward your protein goal. It still counts as protein. As long as the majority of your other sources are complete proteins, you’re good to go. If you don’t want to use up those calories every day on collagen, do half a scoop. In general, a scoop of protein is not going to make or break your results.

How much of my protein should come from whole food versus powder? There isn’t a hard-and-fast percentage or official ratio you need to follow. A good general guideline I like is to keep around 70 to 80% of your protein from whole foods and use powders for the remaining 20 to 30%, if needed. It doesn’t have to be exact. If using powder helps you hit your goal without stress, it’s doing its job.

Do I need collagen if I’m already hitting my protein and using whey? For muscle, no. Whey gives you the full amino acid profile your body needs for repair and recovery, and collagen is missing several essential amino acids, so if you’re consistently hitting your protein you’re covered there. Connective tissue is a different question. Collagen is rich in glycine, arginine and proline, and unless you’re eating nose-to-tail, most of us are probably a bit short on those from our regular muscle meat intake alone.

Can you be allergic to collagen? Collagen is just a specific type of protein, so it would be very rare to have an allergy to it. If you think you’re reacting, take it out for a week and then reintroduce it one more time and see if it happens again. If it does, try a different brand and see if you get the same reaction.

Which protein powder is best for women over 40? The same one that’s best for anyone else, which is whichever complete protein you’ll actually use consistently. Whey isolate if you want the fastest and lowest lactose, plant if you’re dairy-free, casein if you want something slower. What matters far more than the type is whether you’re hitting your protein target for the day.

Is protein powder necessary? No. It’s a convenience tool. If you’re hitting your protein from food, you don’t need it. If you’re not, it’s one of the easiest ways to close the gap.

How much protein do I actually need? For the women I work with, at least 1 gram per pound of body weight per day. That number moves a little depending on whether you’re dieting, maintaining or building, but if you want one target to aim at, that’s it.