In humans, studies that investigate links between serotonin and creatine supplementation find that 21 trained males, given creatine via 22.8g creatine monohydrate (20g creatine equivalent) with 35g glucose, relative to a placebo of 160g glucose, was found to reduce the perception of fatigue in hot endurance training, possibly secondary to serotonergic modulation, specifically attentuating the increase of serotonin seen with exercise (normally seen to hinder exercise capacity in the heat) while possibly increasing dopaminergic activity (conversely seen to benefit activity in the heat).
Recommended Dose: 3-6 grams before or during exercise. A ratio of two parts leucine to one part each of isoleucine and valine appears to be most beneficial. As Krissy Kendall, PhD, explains in "The Top 7 Supplements to Boost Endurance Performance," BCAAs can be just as effective for endurance athletes like runners, rowers, and cyclists as they can be for lifters and bodybuilders.
Electrolytes derive mainly from minerals in the diet and they maintain fluid balance and assist the nervous system to perform muscle contractions. Electrolytes are sodium, potassium, magnesium, calcium and chloride, bicarbonate, phosphate, sulfate. Exercisers are particularly dependent on sodium and potassium balance. Carbohydrates are important for fueling exercise, including vigorous weight training, and in post-exercise energy replacement nutrition. Carbohydrates, mostly sugars, are formulated in sports drinks with electrolytes such as sodium chloride and potassium and sometimes magnesium.
Due to this relative deficiency-state in vegetarians and vegans, some aspects of creatine supplementation are seen as more akin to normalizing a deficiency, rather than providing the benefits of supplementation. In young vegetarians, but not omnivores, creatine supplementation can enhance cognition. The increased gain in lean mass may be more significant in vegetarians, relative to omnivores. Supplementation of creatine in vegetarians appears to normalize the gap in storage between vegetarians and omnivores. This is possibly related to a correlation seen in survey research, where vegetarianism and veganism appear to be more commonly affected by some mental disorders like anxiety and depression.
Entry into neural tissues in general is mediated by the secondary creatine transporter (CrT-2) known as SLC6A10, which is the same transporter that is active in a male’s testicles. CrT-2 belongs to the family of SLC6 transporters that act to move solutes across the membrane by coupling transport with sodium and chloride. Genetic deletions in the 16p11.2 region, which encodes both SLC6A8 and SLC6A10 can result in severe mental retardation in humans and is one of the causes of “Creatine Deficiency Syndrome.” Creatine Deficiency Syndrome is not only caused by lack creatine transporter expression, however, as creatine synthesis is also critical for neural function.. Retardation caused by defective creatine synthesis can be reversed with creatine supplementation and dietary changes.