5 Evidence-Backed Supplements That May Improve Your Fitness

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Every top 5 list for supplements will vary due to marketing, opinions, fads and hottest trends. This is a money-making industry and hands are out and ready to take your cash. Honestly, we don't require supplements to cut fat, build muscle, and enhance performance.

In fact, we can obtain most of our essential nutrients from healthy food intake to create the body we desire. Before you stop reading, a few supplements have shown promise with enhancing our fitness. Studies for more conclusive information are always ongoing.

Supplements remain unregulated and as a consumer should be approached with buyer-beware. Before handing over hard-earned cash for supplements, it's recommended to research the products, talk to your doctor and track your own progress.

Make an informed decision before purchasing a bunch of supplements thought to produce a fitness miracle. Now that you are reading with an open mind, the following supplements are backed by scientific evidence and often asked about for improving fitness.

Fish Oil

Fatty fish contains docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) which are both types of omega-3 fatty acids.

Omega 3 fats have already been linked to a decreased risk of heart disease and now studies similar to one published in The Journal of the International Society of Sports Nutrition are seeing neuromuscular improvement for endurance athletes with fish oil supplementation. 

Another study conducted on female elite soccer players and reported by The Journal of Sports Science and Medicine concluded that “the study suggests that supplementation with DHA produced perceptual-motor benefits in female elite athletes and that DHA could be a beneficial supplement in sports where decision making and reaction time efficiency are of importance.” 

BCAAs (Branch Chain Amino Acids)

Branched-chain amino acids (BCAAs) contain leucine, isoleucine, and valine which have an important role in protein synthesis and glucose uptake into our cells. These amino acids have important functions post-exercise and for overall muscle building and recovery

BCAAs can be obtained by eating lean protein. People on certain specialized diets or athletic training plans may use them. But for many people, supplementation is not necessary because they can get the nutrients from their daily diet.

Some research studies have investigated the different ways that branched chain amino acid supplements may also be useful if you are not getting enough in your daily diet.

One systematic research review published in a 2017 issue of Nutrients found that BCAA supplementation can be helpful to reduce exercise-induced muscle damage, as long as the extent of muscle damage was low-to-moderate. Study authors also noted that the best supplementation strategy involved taking the supplement before exercise and that a high daily BCAA intake (more than 200 mg per kg of bodyweight per day) for at least 10 days and beginning at least seven days before the damaging exercise.

Vitamin D

According to the National Institutes of Health, most people in the United States consume less than recommended amounts of vitamin D. Dairy products contain vitamin D and it is also absorbed through natural sunlight. It's essential to include a source of vitamin D daily to maintain optimal health and fitness. 

 An abstract published by Medicine and Science in Sports and Exercise states “vitamin D may improve athletic performance in vitamin D-deficient athletes” and “may also protect the athlete from several acute and chronic medical conditions.” 

According to an article published in the Scandinavian Journal of Medicine & Science in Sports “despite the limited evidence available at the time, athletes and trainers in the early 20th century believed that UVB radiation was beneficial to athletic performance."

"Accumulating evidence supports the existence of a functional role for vitamin D in skeletal muscle with potentially significant impacts on both the performance and injury profiles of young, otherwise healthy athletes.”


Caffeine is typically one of the top ingredients for fat burning supplements, weight loss products, and performance enhancers. A great cup of black coffee can deliver the metabolism boost plus provide bonus antioxidants. More is not better however when it comes to caffeine and proceed with caution before using this product.

In an International Society of Sports Nutrition position stand: caffeine and performance “It is evident that caffeine is indeed ergogenic to sport performance but is specific to the condition of the athlete as well as intensity, duration, and mode of exercise.”

Also indicated in a 2014 Harvard Health Publication, “not only is caffeine a brain stimulant … but it also blocks receptors giving you a surge of energy and potentially improving mental performance and slowing age-related mental decline.” Guidelines suggest that ingesting a low-to-moderate doses of caffeine, ranging from 3 to 6 mg per kilogram of body weight approximately 60 min prior to exercise can provide benefits.


Creatine is one of the most researched and widely used supplements to enhance muscle building and strength. Creatine supplies energy to your muscles for contraction.

Creatine is naturally occurring in the body but also found in foods like meat, dairy and eggs. Creatine monohydrate is one of the most popular supplements on the market for athletes but there is also some emerging evidence that it may provide benefits for older adults in the prevention of sarcopenia (loss of skeletal muscle mass).

Traditionally, creatine monohydrate was believed to primarily benefit athletes who participated in high-intensity intermittent resistance/power type activities. But there is some evidence that it may also improve muscle glycogen storage for athletes who deplete large amounts of glycogen during training and/or during sporting events.

Research suggests that creatine supplementation in adults is relatively well tolerated, at a dose of 3-5 grams per day or 0.1 g per kilogram of body mass per day.

11 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Lewis EJ, Radonic PW, Wolever TM, Wells GD. 21 days of mammalian omega-3 fatty acid supplementation improves aspects of neuromuscular function and performance in male athletes compared to olive oil placebo. Journal of the International Society of Sports Nutrition. 2015;12:28. doi:10.1186/s12970-015-0089-4

  2. Guzmán JF, Esteve H, Pablos C, Pablos A, Blasco C, Villegas JA. DHA- rich fish oil improves complex reaction time in female elite soccer players. Journal of Sports Science & Medicine. 2011;10(2):301-5.

  3. Fouré A, Bendahan D. Is branched-chain amino acids supplementation an efficient nutritional strategy to alleviate skeletal muscle damage? A systematic reviewNutrients. 2017;9(10):1047. Published 2017 Sep 21. doi:10.3390/nu9101047

  4. National Institutes of Health Office of Dietary Supplements. Vitamin D.

  5. Cannell JJ, Hollis BW, Sorenson MB, Taft TN, Anderson JJ. Athletic performance and vitamin D. Medicine & Science in Sports & Exercise. 2009;41(5):1102-10. doi:10.1249/MSS.0b013e3181930c2b

  6. Hamilton B. Vitamin D and human skeletal muscle. Scandinavian Journal of Medicine & Science in Sports. 2010;20(2):182-90. doi:10.1111/j.1600-0838.2009.01016.x

  7. Goldstein ER, Ziegenfuss T, Kalman D, et al. International society of sports nutrition position stand: Caffeine and performance. Journal of the International Society of Sports Nutrition. 2010;7(1):5. doi:10.1186/1550-2783-7-5

  8. Harvard Health Publishing. Caffeine and a healthy diet may boost memory, thinking skills; alcohol’s effect uncertain.

  9. Mielgo-Ayuso J, Marques-Jiménez D, Refoyo I, Del Coso J, León-Guereño P, Calleja-González J. Effect of caffeine supplementation on sports performance based on differences between sexes: A systematic review. Nutrients. 2019;11(10):2313. Published 2019 Sep 30. doi:10.3390/nu11102313

  10. Cleveland Clinic. Creatine and creatine supplements.

  11. Antonio, J., Candow, D.G., Forbes, S.C. et al. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?. J Int Soc Sports Nutr 18, 13 (2021). doi:10.1186/s12970-021-00412-w

By Darla Leal
Darla Leal is a Master Fitness Trainer, freelance writer, and the creator of Stay Healthy Fitness, where she embraces a "fit-over-55" lifestyle.