Yes, whey protein has lactose. Whey comes from milk, and lactose comes with the territory. Whey concentrate has the most — roughly 5–8% lactose by weight. Whey isolate has less, around 0.5–1%, but it's not zero. If you're lactose intolerant and chugging whey shakes, that explains a few things.
Let's break down exactly how much lactose is in each type of whey, why it matters, and what to reach for instead.
How Much Lactose Is in Whey Protein?
Whey protein starts as a byproduct of cheesemaking. It's literally the liquid left over after milk curdles. Since milk contains lactose, whey does too. How much ends up in your protein powder depends on how aggressively it's been filtered.
Here's the breakdown:
| Whey Type | Protein Content | Lactose Content | Notes |
|---|---|---|---|
| Whey Concentrate (WPC) | 70–80% | 5–8% | Most common, cheapest to produce |
| Whey Isolate (WPI) | 90–95% | 0.5–1% | Extra filtration removes most lactose |
| Whey Hydrolysate | 80–90% | <1% (trace) | Pre-digested; still contains trace lactose |
A standard 30g scoop of whey concentrate delivers roughly 1.5–2.4g of lactose. A scoop of whey isolate? About 0.15–0.3g.
That might sound tiny. But for the 68% of adults worldwide who have some degree of lactose malabsorption (NIDDK), even small amounts can cause problems — especially when you're having a shake every day, sometimes twice.
The "Lactose-Free" Marketing Problem
You'll see whey isolate brands slap "lactose-free" on the label. Technically, that's misleading. The FDA doesn't have a formal definition of "lactose-free" for protein powders the way it does for milk. Many whey isolates test below 1% lactose, so companies round down to zero.
If you have mild lactose sensitivity, you might tolerate whey isolate fine. If you're truly lactose intolerant, "almost zero" and "actually zero" are very different conversations with your gut.
Why Does Whey Protein Cause Bloating and Gas?
Here's the uncomfortable truth: a lot of people drink whey protein and feel terrible afterward. Bloating, gas, stomach cramps, or worse. They assume protein shakes are just like that. They're not.
Lactose malabsorption is the most common culprit. About 68% of the world's adult population — and roughly 36% of Americans — have reduced ability to digest lactose (NIDDK). When undigested lactose hits your large intestine, bacteria ferment it. That fermentation produces gas, draws in water, and creates the bloating-cramping-bathroom combo that nobody signed up for.
But lactose isn't always the only issue. Whey protein can cause digestive problems for several reasons:
- Lactose content — The most likely cause if you're sensitive to dairy
- Casein traces — Even whey isolate can contain small amounts of casein, which some people react to independently of lactose
- Artificial sweeteners — Sucralose, acesulfame potassium, and sugar alcohols like sorbitol can cause GI distress on their own
- Thickeners and gums — Xanthan gum, carrageenan, and other additives can trigger bloating in some people
- Simply too much protein at once — Slamming 50g of any protein in one sitting can overwhelm digestion
So if whey makes your stomach angry, lactose is the first suspect. But it might have accomplices.
Can Lactose-Intolerant People Use Whey Isolate?
The honest answer: some can, some can't.
Whey isolate contains significantly less lactose than concentrate. For people with mild lactose sensitivity, that reduction is often enough to eliminate symptoms. Plenty of mildly lactose-intolerant people use whey isolate without any issues.
But lactose intolerance exists on a spectrum. Some people can handle a splash of cream in their coffee. Others react to the trace amounts in a single whey isolate scoop. There's no universal threshold.
Here's a practical way to think about it:
- Mild sensitivity (you can eat some cheese, a little yogurt) — Whey isolate will probably work for you
- Moderate sensitivity (dairy gives you consistent issues) — Whey isolate is a coin flip. You might tolerate it, or you might not
- Severe intolerance (even small amounts of dairy cause symptoms) — Skip whey entirely. Trace lactose plus possible casein traces isn't worth the gamble
If you've been forcing yourself to push through post-shake discomfort because someone told you "isolate is lactose-free," stop. Feeling terrible after a protein shake is not normal. It's your body telling you something.
What Are the Best Lactose-Free Protein Alternatives?
If dairy is the problem, the fix is straightforward: use a protein that never touched a cow's udder. Here are your best options.
| Protein Source | Lactose | Dairy-Free | Protein per Serving | Best For |
|---|---|---|---|---|
| Beef protein isolate | Zero | Yes | 20–26g | Complete amino acids, no dairy, no bloat |
| Egg white protein | Zero | Yes (no dairy) | 20–25g | High bioavailability, clean taste |
| Collagen peptides | Zero | Yes | 10–20g | Joints, skin, gut health (not a complete protein) |
| Pea protein | Zero | Yes | 20–24g | Plant-based, allergen-friendly |
| Rice protein | Zero | Yes | 15–22g | Easily digested, mild flavor |
| Hemp protein | Zero | Yes | 12–15g | Plant-based, omega-3s, lower protein content |
Beef Protein Isolate: The Closest Match to Whey
If you want whey-level protein without the dairy baggage, beef protein isolate is worth a hard look. It's made from real beef — not dairy — through a hydrolysis process that concentrates the protein and removes the fat.
Zero lactose. Zero casein. Zero dairy anything. That's not a rounding error — it's genuinely zero, because beef was never a dairy product.
The amino acid profile stacks up well against whey too. You're getting all the essential aminos you need for muscle protein synthesis without the GI side effects that send dairy-sensitive people running.
PaleoPro Paleo Protein Powder is made from 100% grass-fed beef protein isolate. No dairy, no soy, no gluten, no artificial sweeteners. If whey has been wrecking your stomach, this is the most direct swap.
The Plant-Based Route
Pea and rice protein are solid options if you want to avoid animal products entirely. The main tradeoff is that most plant proteins are lower in one or more essential amino acids. Many brands blend pea and rice together to get a more complete profile.
The other thing to watch: plant-based protein powders often rely heavily on sweeteners, gums, and flavoring to mask the earthy taste. Read the label. If you're switching away from whey because of digestive issues, make sure you're not trading lactose problems for additive problems.
How to Know If Lactose Is Causing Your Protein Problems
Not sure if lactose is your issue? Here's a simple process.
Common Symptoms of Lactose-Related Protein Issues
Watch for these within 30 minutes to 2 hours after your protein shake:
- Bloating or abdominal distension
- Gas (excessive, uncomfortable)
- Stomach cramps or pain
- Diarrhea or loose stools
- Nausea
- Gurgling or rumbling stomach
The Simple Elimination Test
- Stop using whey protein for 7–10 days. Switch to a non-dairy protein like beef protein isolate or egg white protein. Keep everything else in your diet the same.
- Track how you feel. If the bloating and gas disappear, dairy was almost certainly the problem.
- If you want to confirm, reintroduce whey after the 10-day break. If symptoms come back, you have your answer.
It Might Not Be Lactose
Before you blame lactose for everything, consider other possibilities:
- Artificial sweeteners — Sucralose and sugar alcohols cause digestive issues in many people, independent of lactose
- Serving size — Are you using two scoops when one would do? Large protein doses can cause GI distress regardless of the source
- Speed of consumption — Chugging a shake in 30 seconds versus drinking it over 10 minutes makes a difference
- What else is in the shake — High-fiber additions, certain fruits, or large amounts of fat alongside protein can slow digestion and cause bloating
The elimination test handles most of this. Remove the variable, see what changes.
Frequently Asked Questions
Is whey protein isolate lactose-free?
Not completely. Whey isolate contains roughly 0.5–1% lactose by weight, which works out to about 0.15–0.3g per scoop. Most people with mild lactose sensitivity tolerate this fine, but those with severe intolerance may still react. Despite marketing claims, "lactose-free" whey isolate still contains trace lactose.
Can I take whey protein if I'm lactose intolerant?
It depends on severity. People with mild lactose intolerance often handle whey isolate without problems. Those with moderate to severe intolerance usually do better with a genuinely dairy-free protein — like beef protein isolate or egg white protein — that contains zero lactose by nature, not by filtration.
Does casein protein have lactose?
Yes. Casein is the other major milk protein, and casein-based supplements typically contain lactose. Micellar casein (the most common form) can contain 2–5% lactose. Since casein digests more slowly than whey, the GI effects can feel prolonged in lactose-sensitive people.
Is beef protein powder dairy-free?
Yes. Beef protein isolate is made from beef, not milk. It contains zero lactose, zero casein, and no dairy components whatsoever. It's one of the only high-protein powder options that matches whey's amino acid profile while being completely dairy-free. PaleoPro's beef protein comes from 100% grass-fed, pasture-raised cattle.
What protein powder won't make me bloated?
Start by eliminating the most common bloating triggers: lactose (switch from whey to beef protein, egg white, or a clean plant blend), artificial sweeteners (look for stevia or monk fruit instead of sucralose), and thickeners like carrageenan. A short-ingredient-list protein from a non-dairy source is your safest bet. Check out our list of dairy-free protein shake options for specific recommendations.
How do I know if my protein powder has lactose?
Check the ingredient list and allergen statement. If the protein source is "whey protein concentrate," "whey protein isolate," "milk protein," "casein," or "micellar casein," the product contains dairy and therefore lactose. Even if the label says "lactose-free," whey-based products contain trace amounts. The only way to guarantee zero lactose is to use a protein that isn't derived from milk — beef, egg white, or plant-based options.
Interested in a protein that skips the dairy entirely? Browse PaleoPro's full lineup of dairy-free proteins — grass-fed beef protein, egg white protein, and bone broth collagen. No lactose. No guessing.
Sources:
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). "Definition & Facts for Lactose Intolerance." niddk.nih.gov
- Glanbia Nutritionals. "Spot the Difference: Whey Protein Isolate versus Concentrate." glanbianutritionals.com
- Szilagyi, A., & Ishayek, N. (2018). "Lactose Intolerance, Dairy Avoidance, and Treatment Options." Nutrients, 10(12), 1994. PMC