Energy sustained for workouts and throughout day with caffeine plus citruline malate, taurine, and several other ingredients..
Muscle building BCAAs – leucine, isoleucine, and valine.
Mental function improved with creatine, caffeine, and nitric oxide boosting ingredients.
Addictive. Watch out for addiction and doubling scoops.
Build tolerance fairly quickly, require cycling to maintain positive effects. "Law of diminishing returns".
Gut issues (diarrhoea) and stomach pain.
Colouring and artificial sweeteners. Questionable safety (more research is required).
Caffeine withdrawal headaches.
Depression and anxiety upon withdrawal. May have to wean off product.
Relatively expensive for a product with all-inclusive effective ingredients.
Occasional use might not be overly harmful. There are definite benefits including increased strength and muscle mass. There are additional perks such as creatine being good for mental health/function and more. If you want to avoid too many stimulants and artificial flavours, you can try buying the ingredients separately (BCAAs, creatine, citruline, betaine etc.). However, in powder form their taste is pretty disgusting. Overall, I do not consider these supplements essential. Personally, I am beginning to feel as though the caffeine headaches and stomach issues and not worth the benefits of pre-workout products. I have used them frequently and infrequently over the past decade. I have tried many products and Pre-JYM by JYM Supplement Science (Dr. Jim Stoppani's company) has been the most effective. Maybe the negative symptoms would not avoided if the products were only used sparingly throughout the year.
Eric Astrauskas, Spec. Hons. B.A.(Kinesiology), P.T.S.