Amino Acids as the Foundation of Muscle Growth
Amino acids are the building blocks of muscle — an indispensable part of any sports nutrition programme. The two most frequently discussed categories are BCAA (branched-chain amino acids) and EAA (essential amino acids). While manufacturers often market them similarly, there is an important scientific distinction between the two.
What Are BCAAs?
BCAAs consist of three amino acids:
- Leucine — the primary trigger of muscle protein synthesis
- Isoleucine — energy metabolism and immune function
- Valine — balances other BCAAs, reduces fatigue
BCAAs make up approximately 35% of skeletal muscle amino acids and are metabolised in muscle tissue rather than the liver — making them a quick source of energy and recovery support. Leucine is particularly important, as it activates the mTOR pathway, triggering muscle protein synthesis (Norton & Layman, 2006).
OstroVit BCAA 8-1-1 200g Natural and MST BCAA EAA 40 Servings Fruit Punch Amino Acids are popular BCAA products in Estonia, available at maxfit.ee.
What Are EAAs?
EAAs include all 9 essential amino acids that the body cannot produce on its own:
- Histidine
- Isoleucine (BCAA)
- Leucine (BCAA)
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
- Valine (BCAA)
EAA therefore includes all three BCAAs plus six additional essential amino acids absent from BCAA products.
OstroVit EAA 5750mg 300 caps and XTEND EAA 40 Servings Apple Raspberry are high-quality EAA products available at maxfit.ee. See our full EAA range.
Why Does Science Favour EAAs?
For a long time, it was thought that BCAAs — particularly leucine — were sufficient to stimulate muscle protein synthesis. However, more recent research paints a different picture.
Research shows that muscle protein synthesis is higher when consuming EAAs compared with the same amount of BCAAs (Wolfe, 2017). The reason is straightforward: protein synthesis requires all 9 essential amino acids. If any are missing, synthesis is inhibited — regardless of how much leucine is taken.
| Feature | BCAA | EAA |
|---|---|---|
| Number of amino acids | 3 | 9 |
| Complete protein synthesis | Limited | Yes |
| Price | Lower | Higher |
| Calories per serving | Very low | Low |
| Vegan-friendly | Mostly yes | Mostly yes |
| Best timing | During training | During/after training |
When Does BCAA Still Make Sense?
Although EAA is the more complete option, BCAAs still have their place:
- Fasted training — BCAAs inhibit muscle catabolism when training on an empty stomach
- Long training sessions — reduce central fatigue via the tryptophan-serotonin mechanism
- Budget constraints — BCAAs are cheaper than full EAA formulas
- Taste preference — many prefer BCAA flavour profiles
That said, if you must choose one, prefer EAAs — especially if your daily protein intake is lower than recommended.
Practical Recommendation
If you consume sufficient protein daily (1.6–2.2 g/kg body weight), neither supplement may offer a significant bonus. But if there are long gaps between meals, you train fasted, or need extra recovery support, EAA is the better investment.
Mutant GEAAR EAA Blue Raspberry 420g is a solid value-for-money option for those wanting to try a complete EAA product.
Summary
EAA is the more scientifically justified choice, providing all amino acids required for complete protein synthesis. BCAAs still have their use case — especially during fasted training or on a budget. Browse our amino acid range: BCAA | EAA.
FAQ
Does EAA fully replace BCAA?
Yes, since EAA contains all three BCAA amino acids (leucine, isoleucine, valine) plus six other essential amino acids. In most cases, EAA is the broader and more complete choice.
Are BCAAs suitable for fasted training?
Yes, BCAAs are particularly useful when training fasted — they inhibit muscle breakdown without significantly raising insulin levels, which would otherwise be needed for full amino acid utilisation.
How many amino acids do I need per day?
This depends on goals and diet. Most research recommends 10–15 g of EAA around training, but total daily amino acid intake from food and supplements matters more than any single dose.
References
- Norton, L. E., & Layman, D. K. (2006). Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. Journal of Nutrition, 136(2), 533S–537S.
- Wolfe, R. R. (2017). Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? Journal of the International Society of Sports Nutrition, 14(1), 30.
- Churchward-Venne, T. A., Burd, N. A., Mitchell, C. J., West, D. W. D., Philp, A., Marcotte, G. R., & Phillips, S. M. (2012). Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. Journal of Physiology, 590(11), 2751–2765.
- Fouré, A., & Bendahan, D. (2017). Is branched-chain amino acids supplementation an efficient nutritional strategy to alleviate skeletal muscle damage? A systematic review. Nutrients, 9(10), 1047.
- Stokes, T., Hector, A. J., Morton, R. W., McGlory, C., & Phillips, S. M. (2018). Recent perspectives regarding the role of dietary protein for the promotion of muscle hypertrophy with resistance exercise training. Nutrients, 10(2), 180.
