L-Glutamine is essential for the serious athlete. L-Glutamine is a non-essential amino acid. It can be made in the muscle cells from other amino acids (glutamine acid, valine and isoleucine) and is the most abundant free amino acid in muscle cells.. Stir one heaped teaspoon (4.5g) into 250ml of water or your favourite beverage one to two times daily. Take one hour before a workout. Do not exceed recommended dose. Ensure adequate hydration during and after training - Minimum of six to eight glasses of water daily. After your workout, you want to make sure you get the right nutrients to restore your body to its original state. Holland & Barrett has a range of delicious post workout products to help you to regain your internal balance. From carbohydrates to protein, you can find the post workout products you need below. Click through to individual products to read further details and nutritional information.