Should you take ketones before or after a workout?

November 17, 2025 •

4 min read

According to a 2024 review, research shows a clear trend towards using exogenous ketones primarily for recovery benefits. Deciding the optimal timing for your ketone supplement—before or after a workout—depends on whether your goal is enhanced performance or accelerated recovery.

Quick Summary

The ideal timing for ketone supplementation depends on training goals. Acute intake before exercise may aid performance in endurance events by providing an alternative fuel source. Conversely, post-exercise intake primarily targets recovery by enhancing glycogen resynthesis and boosting muscle protein synthesis signals.

Key Points

Pre-workout for Endurance: Taking ketones before or during prolonged endurance exercise provides an alternative fuel source that can help spare muscle glycogen and enhance performance.
Post-workout for Recovery: The strongest evidence shows ketones significantly boost recovery when taken after exercise, promoting faster glycogen resynthesis and stimulating muscle protein synthesis.
Mental Focus: Both pre- and post-workout ketone use can improve mental clarity and focus, helping to mitigate the mental fatigue that often accompanies intense training.
Dual-Fueling Strategy: For long-duration events, combining ketone esters with carbohydrates provides a dual-fuel approach that optimizes energy efficiency and preserves glycogen stores.
Overtraining Prevention: Post-exercise ketone intake can reduce symptoms of overreaching and inflammation, allowing athletes to tolerate higher training loads and improve long-term adaptation.
Mindful of Intensity: Research is mixed on the benefits of acute, pre-workout ketones for high-intensity, short-duration exercise, with some studies showing potentially negative impacts.
Timing is Contextual: The optimal time to take ketones depends entirely on your training goal—performance enhancement for endurance efforts versus accelerated recovery for heavy training periods.

Ketones for Performance: Taking Them Before or During a Workout

When consumed before or during exercise, exogenous ketones are designed to provide an additional fuel source for your body. This can be particularly beneficial for endurance athletes, as ketones can help spare your body’s glycogen stores, delaying fatigue and extending performance. In effect, ketones allow your body to use a more efficient, cleaner-burning fuel, enabling you to do more work with less oxygen. The concept works like a hybrid car, running on two fuel sources simultaneously to optimize efficiency.

The "Dual Fuel" Advantage

By supplementing with ketones alongside carbohydrates, athletes can leverage a dual-fuel approach, which can be especially valuable during prolonged endurance activities. Research suggests that this strategy can help lower blood lactate levels during exercise, which is often associated with less carbohydrate burning. This leaves more glycogen available for later, higher-intensity efforts. Some studies in cyclists have shown that combining ketones with carbohydrates improved time trial performance by a small but meaningful margin.

However, the research on performance benefits is not uniform. Some studies, particularly those involving shorter, high-intensity efforts, have shown mixed results or even impaired performance. This could be due to several factors, including the type of ketone supplement (esters vs. salts) and potential effects on blood acid-base balance.

Ketones for Recovery: Taking Them After a Workout

This is where the science is becoming increasingly clear and compelling. Post-exercise ketone supplementation has shown significant benefits for recovery, which is critical for athletes, especially during intense, multi-day training blocks or stage races like the Tour de France.

Enhanced Glycogen Resynthesis

Following a strenuous workout, your body needs to replenish its depleted glycogen stores. Combining ketone esters with post-workout carbohydrates has been shown to boost muscle glycogen resynthesis. One study demonstrated that ingesting a ketone ester drink with carbs after exercise led to a 50% higher muscle glycogen content compared to a control group.

Increased Protein Synthesis

Ketones activate key cellular signaling pathways involved in muscle growth and repair, most notably mTORC1. This can significantly upregulate protein synthesis and tissue regeneration, helping your muscles rebuild and adapt more effectively after tough sessions.

Combating Overtraining and Inflammation

Intense training can lead to inflammation and overreaching, which can negatively impact performance over time. Ketones are powerful anti-inflammatory agents that help scavenge free radicals produced during exercise. Studies have shown that athletes taking ketones post-exercise during an overload training block experienced fewer symptoms of overtraining, tolerated higher training loads, and showed improved performance in time trials.

Comparison: Pre-Workout vs. Post-Workout Ketones


Feature	Pre-Workout Use	Post-Workout Use
Primary Goal	Enhance endurance performance, provide extra fuel.	Accelerate recovery, boost glycogen resynthesis.
Benefit Profile	Sustained energy, potential glycogen sparing, improved cognitive focus.	Reduced inflammation, faster muscle repair, enhanced training adaptations.
Best For	Long-duration endurance events like marathons and ultramarathons.	Multi-day competitions or heavy training blocks with multiple sessions.
Evidence Strength	Mixed findings, with some studies showing no benefit or even negative effects on high-intensity efforts.	Stronger evidence supporting benefits, especially for recovery and adaptation during intense training.
Mechanism	Provides an alternative energy source for muscles and the brain.	Boosts glycogen storage and activates muscle protein synthesis signals.
Best Combined With	Standard carbohydrate fuelling for a dual-fuel effect.	Carbohydrates and protein to maximize recovery processes.

Conclusion: Strategic Timing for Optimal Results

The decision to take ketones before or after a workout is not an either/or dilemma, but a strategic choice based on your specific athletic goals. For endurance athletes focused on immediate performance gains, taking a ketone ester supplement about 30-60 minutes before and during prolonged efforts may provide a valuable fuel source and cognitive edge. For those prioritizing faster recovery and adapting to heavy training loads, a post-workout regimen combined with carbs and protein appears to be the more potent strategy. The most compelling evidence points to ketones' role in recovery, including enhancing glycogen replenishment and increasing muscle protein synthesis signals. To maximize benefits, some elite athletes even combine both approaches, using ketones strategically throughout their training cycle. As with any new supplement, start with a moderate dose during a standard training session to assess your individual response before using it for a key race or event. For high-quality, research-backed ketone supplements, you can learn more from reputable sports nutrition sources, such as Ketone.com. Ultimately, aligning your timing with your desired outcome will help you harness the full potential of ketones for your training and recovery.

The Verdict: Strategic Timing is Key

Prioritize Performance? Take ketones before or during long, endurance-based workouts to leverage them as an additional energy source and potentially spare muscle glycogen.
Prioritize Recovery? The most robust evidence suggests significant gains from taking ketones after a workout, as they can accelerate glycogen resynthesis and boost muscle repair.
Consider Combined Use. For athletes in demanding training blocks, using ketones both before/during (for performance) and after (for recovery) could offer a cumulative advantage.
Listen to Your Body. Since individual responses vary, test your personal protocol during training. Start with a lower dose to assess tolerance and effectiveness.
Mind High-Intensity Efforts. Be aware that some research indicates potential drawbacks for short, high-intensity exercise when using ketones acutely before a session.

Frequently Asked Questions

Yes, research suggests that combining ketone esters with carbohydrates is an effective strategy, as it allows you to utilize both energy sources more efficiently for both performance and recovery.

Ketone esters are generally considered superior for athletic performance and recovery, as they can raise blood ketone (BHB) levels more effectively than ketone salts, and are the subject of most positive research.

The research on using ketones for short, high-intensity efforts is mixed, with some studies showing potential impairment. They are generally considered more effective for prolonged endurance activities.

For performance, it is generally recommended to take exogenous ketones about 30-60 minutes before your workout to allow blood ketone levels to rise.

Post-workout ketones accelerate recovery by increasing muscle glycogen synthesis, boosting muscle protein synthesis signals, and providing anti-inflammatory benefits.

The main benefit is the potential for glycogen sparing, where the body uses ketones as an alternative fuel, conserving precious carbohydrate stores for later in the race.

Yes, studies on endurance athletes in heavy training blocks show that post-exercise ketone supplementation can help prevent the symptoms of overreaching and improve training adaptation.

Some individuals may experience mild gastrointestinal discomfort, especially when first trying ketone supplements. However, most users tolerate them well, particularly with smaller doses.