Quick answer
Yes, whey protein is vegetarian in almost every case, because it is a milk protein and no animal is killed to make it. The catch is rennet: whey comes from cheese-making, and the Vegetarian Society counts animal rennet, made from the stomach lining of cows and other ruminants, as not vegetarian. WheyWise checked the labels on each brand's own site on 3 October 2026, and Myprotein Impact Whey is listed as suitable for vegetarians with 72g of protein per 100g in Vanilla; if you want no dairy at all, a plant powder such as Protein Works Vegan Protein 360 Black is the swap.
Whey protein is vegetarian in almost every case. It is a protein from milk, and the Vegetarian Society accepts cheese made with vegetarian rennet. The one exception is whey from cheese set with animal rennet, which strict vegetarians avoid, so it pays to read the suitability line on the label.
Is whey protein vegetarian?
Yes, whey protein suits lacto-vegetarians and lacto-ovo vegetarians, but not vegans. Whey is drained off when milk is curdled to make cheese, then filtered and dried into powder, so no animal is slaughtered for it. Both wheys we checked, from Myprotein and Bulk, are labelled as vegetarian on their own websites, and so are the casein and egg white powders in the table below.
| Protein | Protein per 100g | Vegetarian? | Vegan? |
|---|---|---|---|
| Myprotein Impact Whey (Vanilla) | 72g | Yes, per myprotein.com | No |
| Bulk Pure Whey Protein (Chocolate) | 71g | Yes, per bulk.com | No |
| Myprotein Impact Micellar Casein | 79g | Yes, per myprotein.com | No |
| Myprotein Egg White Powder (Unflavoured) | 77g | Yes, per myprotein.com | No |
| Protein Works Vegan Protein 360 Black (Chocolate Silk) | 79g | Yes | Yes |
Myprotein and Bulk labels checked 3 October 2026; Protein Works label checked 23 September 2026. Collagen and gelatine are made from animal tissue and are not vegetarian.
Why might whey not be vegetarian?
Because of rennet, the enzyme used to curdle milk into cheese. The Vegetarian Society's guide to vegetarian cheese says animal rennet is made from the lining of the stomachs of ruminant animals and is not vegetarian, while microbial rennet, made by fermenting a fungus, and thistle rennet are vegetarian. Whey made alongside a cheese set with animal rennet is the case strict vegetarians question, and the brand is the only one who can tell you which rennet its supplier used.
How do you check if a protein powder is vegetarian?
Look for a suitable-for-vegetarians line on the label or product page, and treat the Vegetarian Society Approved trademark as the strongest proof. The Society's trademark criteria exclude animal rennet and any other by-product of slaughter, gelatine and isinglass, and allow only free-range eggs. A brand's own “suitable for vegetarians” claim, which is what Myprotein and Bulk show, is the brand's word rather than an independent check. If neither is on the label, email the brand and ask which rennet its whey supplier uses.
Labelled suitable for vegetarians
MyProtein Impact Whey Protein Powder
960g bag
A whey Myprotein labels as vegetarian, at a mid-market price per gram of protein.
or compare all UK prices →Labelled suitable for vegetarians
Pros
- + Listed as suitable for vegetarians on myprotein.com, checked 3 October 2026
- + 72g of protein per 100g in Vanilla, 22g in a 30g scoop
- + £1.27 per 25g of protein in the 900g Vanilla bag at £32.99
Cons
- – A brand claim, not a Vegetarian Society trademark
- – Contains milk, so not vegan
●Nutrition per scoop · 21.6g protein in 30g▼
Protein makes up 72%
of this 30g scoop · 113 kcal total
What can vegetarians use instead of whey?
A plant protein is the clean swap if you want to avoid the rennet question entirely. Protein Works Vegan Protein 360 Black has 79g of protein per 100g in Chocolate Silk, against 72g for Myprotein Impact Whey Vanilla, and is suitable for vegans as well as vegetarians. Egg white powder is another dairy-free option for lacto-ovo vegetarians. For ranked picks across whey, egg and plant, read the best vegetarian protein powder UK guide, or compare plant proteins on the vegan protein price comparison.
Vegan, so no rennet question
Protein Works Vegan Protein 360 Black
2kg bag
The dairy-free answer for a vegetarian who would rather not check rennet at all.
or compare all UK prices →Vegan, so no rennet question
Pros
- + 79g of protein per 100g in Chocolate Silk, checked 23 September 2026
- + Plant protein, suitable for vegans and vegetarians
- + Protein Works holds 4.7 out of 5 on Trustpilot from 53,046 reviews, checked 22 September 2026
Cons
- – Plant protein texture is grainier than whey
- – Fewer flavours than the Protein Works whey range
●Nutrition per scoop · 19.8g protein in 25g▼
Protein makes up 79%
of this 25g scoop · 90 kcal total
Frequently asked questions
Is whey protein suitable for vegetarians?
Usually, yes. Whey is a milk protein, so it suits lacto-vegetarians. The only thing to check is whether the cheese it came from was made with animal rennet, which the Vegetarian Society says is not vegetarian. Myprotein Impact Whey and Bulk Pure Whey Protein are both listed as suitable for vegetarians on their own websites, checked 3 October 2026.
Is whey protein vegan?
No. Whey comes from milk, so it is not vegan. Vegans need a plant protein such as pea, soy or a blend. Protein Works Vegan Protein 360 Black, for example, has 79g of protein per 100g in Chocolate Silk, checked 23 September 2026 on theproteinworks.com.
What are the best protein supplements for vegetarians?
Lacto-vegetarians can use whey, casein and plant proteins, and lacto-ovo vegetarians can add egg white protein. Whey is usually the cheapest per gram of protein: Myprotein Impact Whey costs £1.27 per 25g of protein in the 900g Vanilla bag, checked 3 October 2026. For ranked picks, see the WheyWise best vegetarian protein powder guide.