Creatine? Yes, please!
Creatine is one of the best researched supplements out there, and one that is consistently found to have significant, positive benefits. I recommend it to virtually every person I train (and virtually everyone I know, as my friends and family can attest.) Recently, the first study looking at creatine use in perimenopausal women was published and it too showed solid, positive results. The women in this study took creatine or a placebo for 8 weeks. Those who took creatine demonstrated improved alertness, executive function and reaction time, as well as reporting perceived improvements in fatigue, mood swings and concentration.
Creatine is most commonly used to assist in building muscle, and it is incredibly good at that too. A meta-analysis published in the Journal of Strength and Conditioning Research found that creatine supplementation along with weight training resulted in gaining 2.5 pounds more muscle than those doing the same workouts without creatine supplementation. 2.5 pounds does not sound like a lot, but it is a meaningful amount of lean mass, and anyone who is working out to gain muscle knows that each pound requires a meaningful amount of work.
Most people do well with 5g of micronized creatine a day, and you can put that into a protein shake or any other beverage. I would not recommend messing around with the creatine gummies that are popular right now, as they often do not actually have any creatine in them, unfortunately.