Ingredients to look for (and avoid) in a pre-activity supplement

Juni 02, 2026

Pre-Activity Shot and ride essentials laid out at dawn, illustrating the endurance-calibrated approach to pre-effort supplementation

There are more than 10,000 pre-workout products on the market. Most of them were designed for weightlifters: heavy on stimulants, designed to produce a noticeable buzz inside 20 minutes, and built around proprietary blends that hide the actual doses of each compound. For an endurance athlete looking for a clean pre-effort supplement that supports a 90-minute hard ride, a 3-hour long run, or a 6-hour gravel race, almost none of these products are appropriate. The endurance use case has different physiological demands, and the label criteria that flag a good pre-activity product for an endurance athlete are not the criteria that the broader pre-workout category optimises for.

This article walks through the ingredients endurance athletes should look for in a pre-activity supplement, the ingredients to avoid or question, and the label-reading skills that separate a useful product from a marketing one. For the broader framework of what to do in the 60 minutes before a hard session, see The 60-minute pre-training guide. For the broader debate between plant-based and synthetic formulations, see Natural vs synthetic pre-workouts.

What ingredients should a pre-activity supplement for endurance contain?

The endurance use case calls for ingredients that support sustained cellular energy production, controlled sympathetic activation, oxidative defence, and effective fuel delivery, without the GI cost that would compromise a multi-hour effort. The compounds with the strongest published evidence in this specific use case are listed below.

1. Standardised olive leaf extract delivering Oleuropein

Mechanism: mitochondrial membrane support, electron transport chain efficiency, modulation of mitochondrial calcium uptake. Oleuropein has documented effects on muscle mitochondrial bioenergetics response to exercise in human studies (published in The Journal of Physiology), and is one of the most bioavailable polyphenols in the literature. The dose range with published human evidence for endurance-adjacent outcomes is 40 to 100 mg of Oleuropein per day from standardised extract, with the higher end appropriate for acute pre-effort priming.

2. Caffeine in moderate doses (80 to 200 mg per serving)

Mechanism: adenosine receptor antagonism, increased fat oxidation, reduced perceived exertion, sympathetic activation. The ergogenic effect of caffeine for endurance exercise is one of the most well-documented in sports nutrition. A meta-analysis published in the Scandinavian Journal of Medicine and Science in Sports documented a typical performance improvement of 3 to 6% in endurance protocols at moderate doses (3 to 6 mg per kg of body weight, or roughly 200 to 400 mg for most athletes). The endurance-relevant point is that lower doses (80 to 150 mg per serving) sit safely inside the ergogenic range without producing the GI side effects, sleep disruption, or sympathetic overshoot that higher doses do. Natural caffeine sources (Guarana, green tea) deliver caffeine alongside tannins and other compounds that slow absorption and produce smoother plasma levels than isolated caffeine.

3. Nitric oxide pathway support (L-citrulline or nitrate sources)

Mechanism: increased nitric oxide production, vasodilation, improved blood flow to working muscles, reduced oxygen cost of submaximal effort. The two main routes are L-citrulline (which converts to L-arginine, the substrate for nitric oxide synthase) and dietary nitrate (typically from beetroot, which is converted to nitric oxide via the nitrate-nitrite-NO pathway). Both have published evidence in endurance contexts. Effective doses for L-citrulline sit at 6 to 8 g per day for chronic use, with single pre-effort doses in the 3 to 8 g range typically used in trials. For nitrate, the typical effective dose is 5 to 8 mmol of nitrate (roughly equivalent to 500 ml of concentrated beetroot juice). Either pathway is acceptable; both require dosing transparency on the label.

4. Magnesium (40 to 100 mg per serving as part of a daily approach)

Mechanism: cofactor for ATP synthesis, required for every molecule of biologically active ATP, supports neuromuscular function. The pre-activity dose is not where most magnesium intake should come from (chronic baseline matters more than acute), but a moderate magnesium presence in a pre-activity formula supports the cellular machinery that the effort about to start will depend on. Forms vary: well-tolerated forms like magnesium bisglycinate are preferable to magnesium oxide.

5. B-vitamin complex at meaningful doses (around 50% of nutrient reference value or above)

Mechanism: cofactors at multiple steps in carbohydrate, fat, and protein metabolism. B1, B2, B3, B5, B6, and B12 each support specific enzymatic reactions that convert fuel into the ATP your muscles will use during effort. A pre-activity formula that delivers the full B-complex at meaningful percentages of NRV ensures the cofactor status is not the limiting factor in cellular energy production.

6. Vitamin C from a whole-food source (Acerola extract)

Mechanism: supports antioxidant defence enzyme function, contributes to the recovery side of the redox balance, supports iron absorption from food eaten alongside. Acerola is one of the highest natural sources of vitamin C and provides the compound alongside its natural cofactor matrix. A moderate dose (40 to 80 mg per serving) supports the use case without falling into megadose territory.

7. Acetyl-L-carnitine

Mechanism: transport of long-chain fatty acids into mitochondria for oxidation, support for cognitive focus and reduced perception of fatigue. The acetylated form crosses the blood-brain barrier and is the form most studied for cognitive effects alongside the metabolic ones. Effective doses for athletic applications typically sit at 500 to 2,000 mg per day, with single doses in the 300 to 750 mg range used acutely.

8. Carbohydrate at a moderate dose (15 to 25 g per serving)

Mechanism: rapidly available substrate for the start of effort, prevents the early-effort glucose dip that fasted starts can produce, supports cognitive function in the activation window. The dose should be enough to matter physiologically without being so high that it triggers insulin spike and rebound, or causes GI distress in athletes with sensitive guts. The 15 to 25 g range fits the use case for most athletes.

Which common pre-workout ingredients should endurance athletes avoid?

The next list covers ingredients that either work poorly for the endurance use case, are routinely underdosed in commercial products, or are wrapped in proprietary blend structures that prevent the buyer from evaluating them at all.

1. Caffeine doses above 300 mg per serving

The ergogenic ceiling for caffeine in endurance sport is reached well below the doses most pre-workout products deliver. Higher doses produce diminishing performance returns and increasing side effect costs: GI distress during long efforts, elevated heart rate at submaximal effort, sleep disruption when the effort is late in the day, and sympathetic overshoot that can tip activated into anxious. A typical pre-workout with 300 to 400 mg of caffeine per serving is calibrated for the gym, not for a 3-hour ride.

2. Beta-alanine at any dose, for pre-effort use

Beta-alanine has published evidence for short-duration, high-intensity efforts (1 to 7 minutes) where lactate buffering matters most. It is not an ergogenic aid for sustained endurance work above this duration, and most published positive results come from chronic loading protocols (4 to 12 weeks of consistent intake) rather than acute pre-effort doses. The tingling paresthesia that beta-alanine produces is a histamine-receptor side effect, not a sign the compound is working. Pre-workout products that emphasise the tingle as a feature are selling sensation, not performance.

3. Any ingredient in a proprietary blend

A proprietary blend is a list of ingredients with a single combined weight on the label, hiding the actual dose of each component. The marketing reason for this structure is to disguise the use of cheap underdosed ingredients while implying a more expensive formulation. The practical implication for an endurance athlete is that the dose cannot be evaluated against the published research, and the label provides no way to know whether the active compound is present at an effective amount or as a fairy dust trace. Every ingredient that matters should have its own line on the label with its own dose.

4. Artificial sweeteners at high doses

Sucralose, aspartame, and acesulfame potassium are individually well-tolerated in most people at moderate doses. At high doses, particularly during endurance efforts where the gut is already under stress, some athletes experience GI distress. The endurance use case calls for either natural sweeteners (small amounts of sucrose, fruit juice concentrates) or low-dose artificial sweeteners, not the heavy artificial sweetener loads typical of gym-focused pre-workouts.

5. BCAAs as a standalone pre-effort intervention

Branched-chain amino acids have published applications in protein synthesis and muscle recovery contexts, but the evidence for BCAAs as an acute pre-effort ergogenic aid in endurance athletes is weak. BCAAs are useful as part of a complete formulation (where they contribute to the amino acid profile and may modestly reduce central fatigue), but a pre-workout product whose primary marketing claim is "high BCAA content" is misaligned with the published endurance evidence. Look for BCAAs as a complement to other ingredients, not as the headline.

6. Megadose vitamin C or vitamin E in isolation

The research on antioxidant supplementation and training adaptation, covered in the Plant-based antioxidants guide, indicates that high-dose isolated synthetic vitamin C (above 1,000 mg per day) and vitamin E (above 400 IU per day) taken close to training can blunt some training adaptations. Pre-workout products with megadose isolated vitamins in this range are not endurance-friendly, regardless of how natural the marketing positioning is.

Quick reference table

Ingredient	What it does	Evidence level	Effective dose (acute)	Red flag
Oleuropein (from olive leaf extract)	Mitochondrial membrane and bioenergetics support	Strong	40 to 100 mg, standardised	"Olive leaf extract" with no oleuropein percentage on the label
Caffeine	Adenosine antagonism, reduced perceived exertion, increased fat oxidation	Strong	80 to 200 mg per serving	Above 300 mg, or undisclosed total in a blend
L-citrulline	Nitric oxide production via L-arginine, vasodilation	Strong	3 to 8 g (chronic 6 to 8 g daily)	Trace doses under 1 g
Dietary nitrate	Nitric oxide via nitrate-nitrite-NO pathway, reduced O2 cost	Strong	5 to 8 mmol	Unstandardised beetroot powder, no nitrate content stated
Magnesium	ATP cofactor, neuromuscular function	Strong (chronic), moderate (acute)	40 to 100 mg in formula context	Magnesium oxide as the dominant form
B-vitamin complex	Cofactors in fuel metabolism	Strong (deficiency correction)	Around 50% NRV or above per B vitamin	Single B vitamin in isolation, megadose B6
Vitamin C (whole-food source)	Antioxidant cofactor, iron absorption support	Moderate	40 to 80 mg from acerola or similar	Synthetic ascorbic acid above 500 mg in isolation
Acetyl-L-carnitine	Fat oxidation transport, cognitive focus	Moderate	300 to 750 mg acute	L-carnitine in non-acetylated form for cognitive claims
Carbohydrate	Immediately available substrate	Strong	15 to 25 g	Above 40 g acute (GI risk) or below 5 g (functionally absent)
Beta-alanine (for endurance)	Lactate buffering	Weak (for sustained endurance)	Not applicable acute	Any acute pre-endurance use; tingle as marketing
Proprietary blends	Undisclosed	Not evaluable	Not applicable	Always a red flag for an informed buyer

How do you read a pre-activity supplement label?

The label reading process for an endurance athlete is straightforward once the criteria above are in mind. Five questions answer most of it.

First, what is the caffeine source and dose per serving? If it is above 300 mg or undisclosed within a blend, the product is not endurance-calibrated. If it is in the 80 to 200 mg range from a named natural source (Guarana, green tea, coffee extract), it sits in the appropriate window.

Second, is every active ingredient listed with its individual dose? If any compound appears only as part of a proprietary blend, the product cannot be evaluated against the research. This is a structural disqualifier, not a soft concern.

Third, are the polyphenol or plant-extract ingredients standardised to their active compounds? "Olive leaf extract 500 mg" tells you nothing without the oleuropein percentage. "Olive leaf extract 500 mg standardised to 20% oleuropein (100 mg)" tells you the dose that will reach your cells. The same principle applies to green tea (EGCG content), beetroot (nitrate content), and other plant extracts.

Fourth, are the doses inside the published evidence range? The table above provides the effective ranges for each compound. A label that lists everything correctly but at doses well below the evidence threshold is selling marketing, not biology.

Fifth, is the formulation calibrated for endurance specifically, or for the general pre-workout category? A product that lists no carbohydrate, no electrolytes, and emphasises high caffeine plus beta-alanine and creatine is a gym pre-workout. A product that lists carbohydrate, electrolytes, polyphenols, and moderate caffeine is calibrated for endurance.

The single biggest signal for whether a pre-activity supplement is endurance-calibrated is the caffeine dose. The endurance ergogenic ceiling for caffeine is reached well below the doses most pre-workout products deliver. Products that lead with 300 mg or 400 mg of caffeine per serving are selling sensation, not sustained performance.

OLEUS Performance Lab

How the OLEUS Pre-Activity Shot maps to the criteria

Each Pre-Activity Shot delivers:

100 mg of Oleuropein from 500 mg of standardised olive leaf extract (mitochondrial support, at the upper end of the published acute dose range)
80 mg of natural caffeine from 364 mg of Guarana extract (inside the endurance ergogenic range, with the smoother absorption profile of plant-matrix caffeine)
675 mg of L-citrulline (nitric oxide pathway via L-arginine and NO synthase, contributing to vasodilation)
375 mg of Acetyl-L-carnitine (fat oxidation transport and cognitive focus, at the acute dose used in studies)
56.3 mg of magnesium and 27.5 mg of sodium (cofactor and electrolyte support)
Full B-vitamin complex (B1, B2, B3, B5, B6) at 50% of nutrient reference value per vitamin, plus B12
40 mg of vitamin C from 80 mg of Acerola extract (whole-food source, moderate dose)
19.3 g of carbohydrate per shot (18 g of sugars from sucrose, providing immediately available substrate)
BCAAs (leucine, isoleucine, valine) as a complement to the broader amino acid profile
Iron bisglycinate, calcium, and copper gluconate as supporting cofactors

Every compound on the label is listed with its individual dose. There are no proprietary blends. The plant extracts are standardised to their active compounds. The caffeine sits inside the endurance ergogenic range and comes from a named natural source. The formula is built for the endurance use case from the ingredient list down.

Frequently asked questions

Is there a problem with stimulant-heavy pre-workouts in principle?

For the gym use case (a 60-minute lifting session, the rare 5K time trial, a high-intensity interval workout), a higher caffeine dose can be appropriate, and the broader pre-workout category serves that population reasonably well. The problem is calibration: a pre-workout designed for a 60-minute gym session is not designed for a 3-hour ride or a 5-hour ultra. The compound demands are different. Endurance athletes using gym pre-workouts often experience GI distress, sympathetic overshoot, or sleep disruption that would not occur with a properly calibrated endurance product.

Should I look for nitric oxide pathway support specifically?

It is one of the strongest evidence-based pre-effort ingredients for endurance. Either L-citrulline or dietary nitrate (typically from standardised beetroot) is acceptable. The mechanism is different (L-citrulline routes through L-arginine and NO synthase; dietary nitrate routes through the nitrate-nitrite-NO pathway), but the functional outcome (vasodilation, reduced oxygen cost) is similar. Products that deliver neither, or that include unstandardised beetroot powder without nitrate content stated, are not engaging this mechanism effectively.

What about creatine in a pre-activity product?

Creatine has strong evidence for high-intensity power output and short-duration efforts, and growing evidence for cognitive support. For sustained endurance work (above 5 to 10 minutes), the ergogenic benefit is weaker. Creatine works best as a chronic daily supplement (3 to 5 g per day for 4+ weeks) rather than as an acute pre-effort ingredient. A pre-activity formula that includes creatine is not wrong, but creatine is not specifically endurance-targeted and chronic loading matters more than the pre-effort dose.

Are natural ingredients always better than synthetic ones?

Not as a blanket rule. The case-by-case answer depends on bioavailability, dose, and matrix effects. Natural caffeine from guarana absorbs more slowly than isolated caffeine, which fits the endurance use case better. Whole-food vitamin C from acerola is preferable to high-dose synthetic ascorbic acid for the same use case. But synthetic forms of magnesium (magnesium bisglycinate, magnesium citrate) often have better bioavailability than naturally chelated forms. The rule is "what the evidence supports for this specific compound in this specific use case," not "natural is always better." For the broader debate, see Natural vs synthetic pre-workouts.

The bottom line

An endurance-calibrated pre-activity supplement contains moderate caffeine from a named natural source, standardised polyphenols with disclosed active-compound doses, nitric oxide pathway support, magnesium and B-vitamins, vitamin C from a whole-food source, acetyl-L-carnitine, and a moderate carbohydrate load. It does not contain proprietary blends, megadose stimulants, or beta-alanine marketed for endurance. Every dose is on the label. The OLEUS Pre-Activity Shot was formulated to meet every criterion on the look-for list.

Sources

This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.