Sorry, you need to enable JavaScript to visit this website.
Home > VITAFRIENDSPKU > PKU JOURNEY > ALL PRODUCTS > PKU sphere<sup>®</sup> Liquid

PKU sphere liquid is a low phenylalanine (phe)* ready-to-drink glycomacropeptide (GMP)-based formula for the dietary management of Phenylketonuria (PKU).

What is PKU sphere® liquid?

A low phenylalanine (phe)* ready-to-drink glycomacropeptide (GMP)-based formula for the dietary management of Phenylketonuria (PKU). It is a blend of whey protein isolate (GMP), essential and non-essential amino acids, carbohydrate, fat (including docosahexaenoic acid – DHA), vitamins and minerals. PKU sphere liquid carton is suitable from 3 years of age.

  • PKU sphere liquid comes in Vanilla flavor and an 8 fl oz serving provides 20 grams of protein equivalent.


What is GMP?

GMP is derived from a natural whole protein source obtained from whey protein in milk, which is produced as byproduct of the cheese making process. Unlike other food sources of protein, GMP is naturally low in phe making it a good option to provide the right balance of amino acids in PKU formulas. GMP protein has been an exciting innovation for PKU and tastes different than amino acids.

How much PKU sphere liquid® can I have per day?

The amount of PKU sphere liquid you need each day will depend on a variety of factors including your age, weight, nutrition needs, and phe tolerance. Your registered dietitian will advise you on how much PKU sphere liquid is right for you.

*Each cartonof PKU sphere liquid contains 36 mg of phenylalanine.

What makes PKU sphere® liquid unique?

PKU sphere liquid is designed with 3 core features to make it easier1 to take your formula everyday:

1. Taste: Contains GMP from a natural whole protein source
• Offering a different taste to amino acid based formulas and is preferred by some individuals with PKU2-5

2. Convenience: Resealable carton
• Easy to take on-the-go to daycare, school, work or when traveling.

3. Low volume: Provides 20 g PE in one 8 fl oz carton
• To help achieve daily protein intake goals

How do I use PKU sphere® liquid?

PKU sphere liquid is easy to use! Simply…

  • Shake vigorously before use. If desired, refrigerate before use.
  • Store in a cool dry place or refrigerate before use. The product should be consumed immediately after opening.
  • However, if this is not possible, seal cap and consume within 4 hours at room temperature or within 24 hours if refrigerated. Re-shake well before use to avoid separation.

PKU Food Balance Game

PKU Food Balance Game – An interactive game to engage children with PKU in learning about food choices on phenylalanine (Phe) or protein restricted diets.

PKU food balance game


Always consult your healthcare professional to determine which Vitaflo products are appropriate for your diet. Not for intravenous use. For enteral use only. Not for use as a sole source of nutrition.


  1. MacDonald, A et al. ‘Ready to drink’ protein substitute is easier is for people with phenylketonuria. J Inherit Metab Dis. 2006; 29(4):526–31.
  2. Lim K, et al. Acceptable low-phenylalanine foods and beverages can be made with glycomacropeptide from cheeses whey for individuals with PKU. Mol Gen Metab. 2007; 31:92(1):176–8.
  3. Van Calcar SC, et al. Improved nutritional management of Phenylketonuria by using a diet containing glycomacropeptide compared with amino-acids. Am J Clin Nutr. 2009; 89(4):1068–77.
  4. Ney, D. Glycomacropeptide for nutritional management of phenylketonuria: a randomized, controlled, crossover trial. Am J Clin Nutr. 2016; 104(2):334–45.
  5. Proserpio C, et al. Exploring Drivers of Liking of Low-Phenylalanine Products in Subjects with Phenylketonuria Using Check-All-That-Apply Method. Nutrients. 2018; 10(9):1179.
Useful resources
Girl with Cmaera [370x510].png