Betaine, also known as trimethylglycine, has gained increasing attention in the fitness and health industries for its impressive effects on performance, body composition, and cellular protection. Naturally found in beets, spinach, and whole grains, betaine has become a key ingredient in many sports supplements due to its proven ability to support strength, power, endurance, and recovery. [1] In this article, we’ll explore what betaine is, the science behind its performance-enhancing properties, and how it can benefit both athletes and those seeking improved metabolic and cardiovascular health.
What is Betaine?
Betaine is a naturally occurring compound composed of the amino acid glycine bonded to three methyl groups. As a methyl donor, it plays a crucial role in numerous physiological processes, including homocysteine metabolism, liver function, cellular hydration, and methylation pathways that support DNA synthesis and protein metabolism. [1] [2]
In the context of exercise and supplementation, betaine is most commonly known for two primary benefits: enhancing muscular strength and power output, and improving hydration status by acting as an osmolyte — a compound that helps cells retain water. [1] Supplementation with betaine anhydrous (the most common form used in research and commercial products) has been shown to support exercise performance, reduce fatigue, and improve body composition.
Betaine for Strength and Power Performance
Betaine has drawn increasing interest as a performance-supporting supplement, especially in resistance training. It is theorized to enhance muscular strength and power through several mechanisms, including its role as a methyl donor for creatine synthesis, its function as an osmolyte for cellular hydration, and its potential impact on muscle protein synthesis.
A 2009 study by Hoffman et al. found that just 7–15 days of betaine supplementation (2.5 g/day) significantly improved muscular endurance and the quality of repetitions during lower-body resistance exercise in recreationally active men. [3] Specifically, participants performed more total reps in the squat exercise and maintained higher power output throughout the set, indicating improved fatigue resistance. Although no changes were observed in upper-body endurance or vertical jump power, this study suggests that betaine may support performance in larger muscle group exercises, potentially by enhancing intramuscular creatine and hydration status.
This finding is reinforced by a 2017 systematic review by Ismaeel, which included seven high-quality randomized trials on betaine’s impact on strength and power. [4] While results were mixed, two studies - one of them also showing increased vertical jump power and isometric strength - reported performance gains of up to 24.6% in upper-body force and 15.9% in power output. Notably, both of these studies used crossover designs, which strengthen confidence in the results.
Van Every et al. concluded in a critical review that while evidence remains inconsistent, betaine may offer performance benefits in contexts involving intensive training or where cellular hydration and recovery are limiting factors. [5] The authors noted that while not all trials show improvements in 1-rep max or sprint performance, the combination of modest gains in endurance, improved repetition quality, and potential lean mass preservation makes betaine a promising adjunct for athletes, particularly during high-volume training blocks.
In summary, while betaine may not consistently increase maximal strength across all settings, it shows real promise for improving training quality, particularly in compound lifts like squats. These improvements can translate into long-term strength and performance gains when paired with progressive resistance training.
Betaine for Muscle Recovery
Beyond its reputation as a performance enhancer, betaine also shows promise for supporting post-exercise recovery. Intense training challenges cellular hydration, increases lactate production, and induces oxidative stress - all of which can hinder recovery and lead to soreness or fatigue. Betaine’s dual role as an osmoprotectant and methyl donor uniquely positions it to counteract these effects.
In a controlled trial by Trepanowski et al., resistance-trained men supplemented with 2.5 g of betaine daily for 14 days. [6] While no major improvements were observed in peak power or maximal strength, subjects performed significantly more repetitions and achieved a higher volume load during a 10-set bench press protocol. Notably, blood lactate accumulation was attenuated post-exercise in the betaine group compared to placebo, suggesting improved metabolic efficiency. Muscle oxygen consumption, assessed via near-infrared spectroscopy, also increased with betaine, indicating better utilization of oxygen during repeated efforts - a potential advantage for faster recovery between sets.
Similarly, Hoffman et al. found that two weeks of betaine supplementation enhanced lower-body muscular endurance and improved the quality of squat repetitions (as measured by the number of reps performed at ≥90% of peak power). [3] These improvements were observed within just one week, underscoring betaine’s rapid onset of action.
Mechanistically, betaine may support recovery through improved cellular hydration, enhanced creatine synthesis via methyl donation, and reduced oxidative stress. Collectively, these findings support the use of betaine as a recovery aid, especially for athletes engaging in high-volume training. While more research is needed to clarify its effects on soreness and oxidative damage, the current data suggest betaine can help maintain training quality and support faster between-session recovery.
Betaine for Body Composition
Betaine has gained attention as a supplement that may help improve body composition—specifically by supporting muscle growth and reducing body fat. This effect seems strongest when combined with resistance training.
In a 6-week study led by Cholewa and colleagues, men who lifted weights and took 2.5 grams of betaine daily gained more lean muscle and lost more fat than those who took a placebo. [2] Notably, the group taking betaine also showed an increase in upper body muscle size (measured by arm circumference) and were able to do more volume in their workouts, suggesting that betaine helped them recover and perform better.
But how does it work?
Betaine helps the body in a few key ways:
- Boosts Protein Synthesis: Betaine donates something called a "methyl group" that your body uses to recycle a compound called homocysteine into methionine. This process increases levels of another compound, S-adenosylmethionine (SAM), which is essential for making new proteins in your muscles. More protein building = more muscle growth. [2]
- Reduces Harmful Byproducts: High levels of homocysteine and a related compound called homocysteine thiolactone (HCTL) can interfere with your body's ability to build muscle by disrupting insulin signaling. [7] Betaine helps lower these compounds, which may protect your muscle-building pathways.
- Increases Muscle Cell Hydration: Betaine also acts as an “osmolyte,” which means it helps your muscle cells hold onto water. [7] This makes them slightly swell, which can send signals that stimulate growth. Think of it like giving your muscle cells a favorable environment to grow and recover.
- Improves Fat Metabolism: Some animal and cell studies show that betaine may reduce fat production and increase fat burning by influencing certain enzymes. [7] It may also help your body use nutrients more efficiently - shuttling them toward muscle instead of fat.
Supporting this, a recent large study (published in 2024) from China found that people who ate the most betaine-rich foods (like whole grains, beets, and spinach) had lower body fat and waist size. [8] Those in the highest intake group had a significantly lower risk of being overweight or obese.
In short, betaine may help you build more muscle and lose more fat - especially when paired with resistance training - by supporting protein synthesis, reducing metabolic stress, and helping your body burn fat more efficiently.
Betaine and Cardiovascular Health
Betaine plays an important role in heart health, mainly by helping to lower levels of a substance in the blood called homocysteine. High homocysteine levels are linked to a higher risk of heart disease, so keeping them in check is considered a good thing. Betaine does this by donating a “methyl group” to help turn homocysteine into methionine - a more harmless compound.
A 2021 meta-analysis of human studies found that betaine supplements reliably lowered homocysteine levels, especially when taken at doses under 4 grams per day. [9] However, taking more than 4 grams daily was sometimes linked to small increases in cholesterol and LDL (the "bad" cholesterol). This suggests that a moderate dose may be best - enough to lower homocysteine without affecting blood lipids in a negative way.
Betaine comes from choline, a nutrient found in many foods. Interestingly, high blood levels of choline have been linked to less favorable health markers, like higher triglycerides and body fat. On the other hand, high levels of betaine are usually associated with better outcomes - like lower blood pressure, healthier cholesterol levels, and less inflammation. Researchers think this may be related to how well a person’s body converts choline into betaine, which can be affected by things like genetics, liver function, and diet. [10]
Studies looking at long-term heart disease risk haven’t found a strong link between how much choline or betaine people eat and whether they develop heart disease. But some research does show that people who get more choline and betaine from their diets tend to have lower levels of inflammation - a key factor in the development of heart disease. [10] [11]
In short, getting moderate amounts of betaine (especially if your diet is low in folate or other B vitamins) may support heart health by reducing homocysteine and inflammation. Just don’t overdo it — high doses of supplements could raise your cholesterol, especially if you already have heart risk factors.
How to Use Betaine
Betaine is most commonly taken as betaine anhydrous, available in powder or capsule form. The standard dose used in research is 2.5 grams per day. This routine helps support strength, endurance, and recovery.
Many athletes combine betaine with creatine, electrolytes, or other performance ingredients to maximize results. It’s especially effective when taken consistently as part of a well-designed training and nutrition plan.
One convenient way to get a full, research-backed dose of betaine is through Outwork Nutrition’s Recovery formula. Each serving delivers 2.5 grams of betaine, along with clinically dosed creatine monohydrate and other evidence-based ingredients
Betaine Benefits Summary
- Boosts Strength & Power: Supports better training volume, more reps, and improved muscular endurance — especially during high-intensity, lower-body lifts.
- Enhances Muscle Recovery: Helps muscles stay hydrated, reduces fatigue, and supports faster recovery between sessions by improving metabolic efficiency and reducing oxidative stress.
- Improves Body Composition: When combined with resistance training, betaine may promote lean muscle gains and reduce body fat by supporting protein synthesis and fat metabolism.
- Increases Workout Capacity: Delays fatigue and helps maintain performance during longer or more intense training sessions — both strength and endurance-focused.
- Supports Heart & Metabolic Health: Helps lower homocysteine, a known cardiovascular risk factor, and may reduce inflammation when taken at moderate doses (<4g/day).
References
1. Arumugam, Madan Kumar et al. “Beneficial Effects of Betaine: A Comprehensive Review.” Biology vol. 10,6 456. 22 May. 2021, doi:10.3390/biology10060456
2. Cholewa, Jason M et al. “Effects of betaine on performance and body composition: a review of recent findings and potential mechanisms.” Amino acids vol. 46,8 (2014): 1785-93. doi:10.1007/s00726-014-1748-5
3. Hoffman, Jay R et al. “Effect of betaine supplementation on power performance and fatigue.” Journal of the International Society of Sports Nutrition vol. 6 7. 27 Feb. 2009, doi:10.1186/1550-2783-6-7
4. Ismaeel, Ahmed. “Effects of Betaine Supplementation on Muscle Strength and Power: A Systematic Review.” Journal of strength and conditioning research vol. 31,8 (2017): 2338-2346. doi:10.1519/JSC.0000000000001959
5. Van Every, Derrick et al. “Betaine Supplementation: A Critical Review of Its Efficacy for Improving Muscle Strength, Power, and Body Composition.” Strength & Conditioning Journal. 2021. Publish Ahead of Print. 10.1519/SSC.0000000000000622.
6. Trepanowski, John F et al. “The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation and associated biochemical parameters in resistance trained men.” Journal of strength and conditioning research vol. 25,12 (2011): 3461-71. doi:10.1519/JSC.0b013e318217d48d
7. Cholewa, Jason M et al. “Effects of betaine on body composition, performance, and homocysteine thiolactone.” Journal of the International Society of Sports Nutrition vol. 10,1 39. 22 Aug. 2013, doi:10.1186/1550-2783-10-39
8. Kuerbanjiang, Maierheba et al. “Association between dietary betaine intake and overweight or obesity.” Scientific reports vol. 14,1 32031. 30 Dec. 2024, doi:10.1038/s41598-024-83646-3
9. Ashtary-Larky, Damoon et al. “Effects of betaine supplementation on cardiovascular markers: A systematic review and Meta-analysis.” Critical reviews in food science and nutrition vol. 62,23 (2022): 6516-6533. doi:10.1080/10408398.2021.1902938
10. Rajaie, Somayeh, and Ahmad Esmaillzadeh. “Dietary choline and betaine intakes and risk of cardiovascular diseases: review of epidemiological evidence.” ARYA atherosclerosis vol. 7,2 (2011): 78-86.
11. Ueland, Per Magne. “Choline and betaine in health and disease.” Journal of inherited metabolic disease vol. 34,1 (2011): 3-15. doi:10.1007/s10545-010-9088-4
