Whey Protein
Evidence summary
Whey Protein has very strong evidence in this guide. The reference dose is 20-40g per serving, with timing listed as post-workout or whenever you need protein. Supplements should support a sound diet and training plan, not replace them.
- Complete amino acid profile
- Fast absorption rate
Benefits
- ✓ Complete amino acid profile
- ✓ Fast absorption rate
- ✓ Convenient protein source
- ✓ Supports muscle recovery and growth
- ✓ Available in many flavours
Possible Side Effects
- ⚠ Bloating if lactose intolerant
- ⚠ Not suitable for dairy allergies
- ⚠ Some products high in added sugar
What Is Whey Protein?
Whey protein is a byproduct of cheese production. When milk is curdled, the liquid whey is separated, filtered, and dried into powder. It contains all nine essential amino acids and is particularly high in leucine — the key amino acid that triggers muscle protein synthesis. It is one of the most popular and well-studied sports supplements on the market.
Concentrate vs Isolate vs Hydrolysate
Whey Concentrate (WPC) is the most common and affordable form. It is roughly 70-80% protein, with the remainder being fat and lactose. Good for most people.
Whey Isolate (WPI) undergoes extra filtering to remove most fat and lactose, yielding 90%+ protein. Better for those with mild lactose sensitivity and anyone wanting fewer calories per scoop.
Whey Hydrolysate (WPH) is pre-digested for faster absorption. It is the most expensive and the taste is often worse. The real-world benefit over isolate is minimal for most lifters.
How It Works
Your muscles need protein to repair and grow after training. Whey is absorbed faster than whole food sources, delivering amino acids to your muscles quickly. That said, total daily protein intake matters far more than timing. If you are hitting 1.6-2.2g of protein per kg of bodyweight from food alone, you may not need a shake at all.
What the Research Says
Whey protein supplementation consistently supports muscle protein synthesis and recovery when combined with resistance training. It is not magic — it is simply a convenient way to hit your protein target. A chicken breast does the same job; whey is just faster and easier after a session.
Who Should Take It
Anyone struggling to hit their daily protein target through whole foods. It is especially useful for people with busy schedules, smaller appetites, or higher protein requirements. One or two shakes a day can bridge the gap.
Who Should Avoid It
People with dairy allergies or severe lactose intolerance should avoid whey entirely. If you experience bloating with concentrate, try isolate first before switching to a plant-based alternative.
Vegan?
Whey protein is not vegan — it is derived from cow’s milk. If you need a plant-based alternative, look for a blended vegan protein powder (pea + rice protein provides a complete amino acid profile). Check out our vegan protein guide for recommendations.
Where to Buy
- Myprotein Impact Whey — from £16.99
- Bulk Pure Whey Protein — from £14.99
- Amazon — Optimum Nutrition Gold Standard — from £24.99
Whey Protein: common questions
What is whey protein used for?
Whey Protein is commonly considered for complete amino acid profile, fast absorption rate, convenient protein source, supports muscle recovery and growth, available in many flavours. The evidence rating in this guide is very strong.
When should I take whey protein?
The practical timing used in this guide is post-workout or whenever you need protein. Consistency and the total daily dose are often more important than a narrow timing window.
How much whey protein should I take?
The reference dosage in this guide is 20-40g per serving. Individual needs vary, so check the product label and speak to a qualified healthcare professional if you have a medical condition, take medication, are pregnant, or are unsure.
Is whey protein vegan friendly?
Not every whey protein product is vegan friendly. Check the source, capsule material, flavouring, and allergen information on the specific product.
Shop smarter
Supplement picks
Products that fit this supplement guide. Swap in tracked affiliate URLs once your accounts are approved.
Grenade Carb Killa Protein Bars
People who want an easy high-protein snack for work, travel, or a calorie-controlled diet.
Merchant
Amazon UK
Around £18-£25 / box
Price checked 5 Jul 2026
Best budget wheyMyprotein Impact Whey Protein
Affordable everyday whey protein for lifters who want simple macro support.
Merchant
Myprotein
From £20 / 1kg
Price checked 5 Jul 2026
Track your supplements in PT Tracker
Log your daily supplements, set reminders, and track your nutrition all in one app.
Download PT Tracker FreeAffiliate disclosure: some links on this page are affiliate links. We earn a small commission at no extra cost to you.
Keep going
Free 12-Week Workout Plan
Get a complete training programme delivered to your inbox — structured, progressive, and designed for all levels. No spam, unsubscribe any time.