Should you take BCAAs before or after your workout? It's one of the most common questions we hear from anyone new to branched-chain amino acids, and the honest answer is that both work.
Branched-chain amino acids have been a staple of sports nutrition for decades, but what actually moves the needle is consistently getting your daily amount and matching your dose to your body weight and training goals.
Here's what the research says about when to take BCAAs, how much to take, and where creatine and other supplements fit into the picture.
In short:
The best time to take BCAAs is 10 to 15 minutes before you train, or sipped during your session if you'd rather have them on hand throughout your workout. On rest days, timing matters less than hitting your total daily amount.
This guide covers what BCAAs are, when to take them around training and rest days, how much you need, whether you can take BCAAs and creatine together, and how BCAAs fit into fasted training or a cut.
What are BCAAs?
BCAA stands for branched-chain amino acids. There are three amino acids in this group: leucine, isoleucine, and valine. Together, they're three of the nine essential amino acids, meaning your body can't produce them itself and needs to get them from food or a supplement.
This sets BCAAs apart from non-essential amino acids like glycine, which your body produces on its own.
Leucine gets most of the attention in BCAA research because it's the amino acid that switches on muscle protein synthesis in skeletal muscle, the process your muscle cells use to repair muscle tissue and rebuild after training. A 2023 review published in Nutrition Research Reviews found that leucine plays a distinct signalling role among the three branched-chain amino acids, triggering the mTOR pathway that drives muscle growth more strongly than isoleucine or valine on their own.
BCAA supplements are usually sold as a powder you mix with water, though capsules are common too. Because they're quicker to digest than a full protein source, they're a popular pre-workout or intra-workout option when you want specific amino acids in your system fast.
What do BCAA supplements actually do?
Combined with resistance training, BCAA supplements have been linked to a range of benefits for muscle performance and recovery. Here's what the research shows:
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They support muscle protein synthesis. The leucine in BCAAs helps trigger the biological signal your body needs to build new muscle protein and supports muscle growth over time.
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They can decrease muscle soreness. A 2024 systematic review and meta-analysis found BCAA supplementation significantly reduced delayed onset muscle soreness (DOMS) and markers of muscle damage in the days following intense exercise, building on earlier findings published in the Journal of the International Society of Sports Nutrition.
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They help protect lean muscle mass. Because BCAAs slow muscle protein breakdown, they're useful for anyone controlling their calorie intake, where the risk of muscle loss is higher.
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They're a lower-calorie alternative to whey protein. For those on low-protein diets or watching their overall intake, BCAA supplements can top up amino acid levels without the extra calories a full protein shake carries.
- They may reduce fatigue during longer sessions. Because BCAAs and tryptophan compete for the same transport route into the brain, some research suggests that BCAA supplementation can delay the onset of central fatigue during prolonged exercise, which is one reason endurance athletes sometimes use them.
Athletes across almost every sport use BCAAs, but they're most popular with strength and physique athletes chasing muscle hypertrophy, muscle preservation during a cut, or faster muscle recovery between sessions.
Should you take BCAAs before or after your workout?
With most dietary supplements, timing comes down to your schedule. With BCAAs, when to take them depends more on what kind of day you've got ahead: a workout day or a rest day.
On workout days
Several studies have compared taking BCAAs before training versus after, and the results have been mixed, with some finding no real difference between the two timings.
However, a 2018 study published in the Journal of Sports Medicine and Physical Fitness found that repeated BCAA supplementation before exercise was more effective at reducing delayed onset muscle soreness and exercise-induced muscle damage than the same dose taken after exercise.
Based on this, taking your BCAAs 10 to 15 minutes before you start training is a reasonable default. If you'd rather sip them throughout your session as blood flow to your working muscles ramps up, taking BCAAs during your workout also delivers solid results for prolonged or higher intensity training.
On rest days
On rest days, exactly when you take your BCAAs is less important. Without a workout to time your dose around, the priority shifts from timing to consistency. Your focus should be on hitting your total daily amount rather than the clock.
A simple approach is to take your rest-day dose in the morning, or split it into two smaller doses throughout the day if that's easier to manage. Your rest day dose helps maintain muscle amino acid availability, even without training to drive it.
How much BCAA should you take?
BCAA dosage isn't one-size-fits-all. How much you need depends on your body weight, training load, and goals, but there are practical ranges to work from.
Daily dosage guide
Most research on BCAA supplementation uses daily doses between 5 g and 20 g, with muscle-building and recovery goals typically toward the higher end. As a rough guide, aiming for around 0.1 g to 0.2 g of BCAAs per kilogram of body weight per day is a sensible starting point:
- A 60 kg person might aim for 6 g to 12 g of BCAAs a day.
- An 80 kg person might aim for 8 g to 16 g of BCAAs a day.
- A 100 kg person might aim for 10 g to 20 g of BCAAs a day.
Splitting your dose
Splitting your daily BCAA intake into two or three smaller doses tends to work better than taking it all at once, since it keeps your amino acid levels topped up rather than spiking and dropping. A simple split could look like:
- 5 g in the morning
- 5 g to 7 g pre-workout
- 5 g in the evening or post-workout
If you're new to BCAA supplements, start at the lower end of your range and adjust from there based on how your training and recovery feel. As with any dietary supplement, check with your doctor first if you're pregnant, breastfeeding, or managing an existing health condition.
BCAA timing for different goals
Your goal changes how much emphasis you should put on BCAA timing.
Building muscle and lean mass
If increasing muscle mass is the priority, the biggest lever isn't exact timing; it's consistency and total protein intake across the day. Take your BCAAs around your workout as outlined above, and make sure your overall diet provides enough protein to support muscle building. If you're unsure how much protein you need, our Nutrition Guide breaks this down in more detail.
Interestingly, a 2024 study found that women in the trial saw a larger reduction in muscle soreness from BCAA supplementation than men did, suggesting the recovery benefits of these specific amino acids may be more pronounced for some people than others. If you're not seeing the results you expected, it's worth tracking your own response rather than assuming one protocol fits everyone.
Fat loss and cutting phases
When you're in a calorie deficit, protecting lean body mass becomes more important, since restricted diets naturally increase the risk of muscle protein breakdown. This is where BCAA supplements are useful, since they help prevent muscle breakdown without adding extra calories to your day.
During a cut, sticking closer to the higher end of your BCAA dosage range and taking a dose around your training session can help offset some of the extra strain a calorie deficit puts on muscle preservation and reduce the risk of muscle loss.
Can you take BCAAs while fasting?
If you train fasted or follow an intermittent fasting routine, you might be wondering whether BCAAs fit into your eating window or break your fast.
Technically, BCAAs do contain a small number of calories, so if you're fasting strictly for metabolic reasons, taking them during your fasting window will interrupt that fast in the strictest sense. Whether that actually matters depends on why you're fasting in the first place.
If your main goal is to preserve muscle size and workout performance during a fasted training session, a small BCAA dose beforehand can help reduce muscle protein breakdown and support muscle performance without derailing your broader fat-loss goals. If your priority is the metabolic benefits of a strict fast, it's more consistent to schedule your BCAAs and your training inside your eating window instead.
There's no universally right answer here; it comes down to your specific goals and how strict you want your fasting protocol to be.
Can you stack BCAAs with creatine or other supplements?
If you're here because you're wondering when to take BCAAs and creatine together, or whether stacking the two makes sense, here's the short version: yes, you can take BCAAs and creatine together, and there's no evidence that combining creatine and BCAAs causes any issues.
Both are naturally occurring amino acid compounds your body already knows how to process, and there's minimal ingredient overlap between them, so stacking creatine and BCAAs doesn't put you at risk of overdoing any single nutrient.
The two supplements also work through different mechanisms, which is why they complement rather than compete with each other.
- Creatine increases available energy for short, intense efforts by supporting adenosine triphosphate (ATP) production, the energy system your muscles rely on during high-intensity movements like heavy lifts or sprints.
- BCAAs are more about supporting muscle protein synthesis and helping decrease muscle soreness after training. This is why so many supplement blends combine creatine and BCAAs in one product.
Creatine works by topping up your muscle creatine stores over time, which is why some people use a short loading dose to reach full muscle saturation faster before settling into a smaller maintenance amount. Because creatine supplementation follows its own dosing pattern and a different long-term strategy to BCAAs, it's worth reading up on separately rather than trying to time it identically to your BCAA doses.
Our Ultimate Guide to Creatine covers creatine monohydrate dosing, loading, and timing in full. Many people simply mix creatine into the same shaker as their BCAAs or add it to a post-workout shake for convenience.
It's also worth noting that BCAAs work best as part of a complete picture rather than in isolation. A 2017 review from the Gatorade Sports Science Institute found that BCAA supplementation alone, without the other essential amino acids, doesn't maximise muscle protein synthesis the way a complete protein or EAA supplement does.
If you're already meeting your protein needs from food or a whey protein shake, BCAAs work as a top-up around training rather than a replacement for a complete source of essential amino acids.
Common BCAA timing FAQs
Can you take BCAA and creatine together?
Yes. There's no research suggesting BCAAs and creatine interact negatively, and many people take both daily. Since they work through different pathways, combining creatine and BCAAs is considered safe and, for many, complementary.
Should I take BCAA before or after a workout?
Both timings work, though research leans slightly toward taking BCAAs before training for reducing muscle soreness. If you're not fussed either way, consistency matters more than precise timing.
Do I need to take BCAAs on rest days?
You can, and it may help maintain muscle amino acid levels, but it's not essential. Focus on your total daily protein intake rather than on a specific rest-day dose.
How much BCAA should I take a day?
Most research supports a range of 5 g to 20 g daily, roughly 0.1 g to 0.2 g per kilogram of body weight, split across two or three doses.
Can BCAAs help with weight loss?
BCAAs aren't a weight loss supplement on their own, but by helping protect lean muscle mass during a calorie deficit, they can support a healthier body composition outcome while you're losing fat.
The bottom line on BCAA timing
Getting the timing of your BCAAs right isn't complicated. Take them 10 to 15 minutes before training, or sip them during your session, and don't stress too much about exact timing on rest days. What matters most is total daily intake, consistency, and matching your dose to your training and goals.
There's no single best supplement for everyone, so if you're deciding between BCAA products, our Amino Acids range includes a few different ratios depending on whether muscle building, recovery, or general amino acid support is your priority.
For a full breakdown of training and diet, check out our Training Guide!
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