"The citrulline pump is real. Focus is locked in from warm-up to last set. This is the pre-workout I've been looking for."
Marcus V. — competitive lifter
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OP Sentinel Pre-Workout - Sour Raspberry
€42,95
HIGH-STIM
ATHLETE FORMULATED
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10g L-Citrulline — clinical pump & endurance dose
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5g Betaine Anhydrous — strength & power output
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5g L-Tyrosine — focus under heavy load
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Layered caffeine system — no crash
Clinically Dosed
Free shipping over €50
14-day returns
Product type:
High-stim pre-workout
Servings per container:
40 servings
Serving size:
1 scoop (10g)
Key ingredient:
L-Citrulline 10g
Recommended use:
20–30 min before training
Suitable for:
Experienced athletes only
Product Details
High-Output Performance Pre-Workout
SENTINEL is a high-stim pre-workout built for experienced athletes who train with intent.
Maximum focus. Sustained energy. Relentless output.
No comfort formula.
No filler ingredients.
Only what performs.
Who It’s For
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Heavy strength training
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High-intensity bodybuilding sessions
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Late-day or mentally demanding workouts
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Athletes who tolerate strong stimulants
If “a little energy” isn’t enough — this is your tool.
Performance-Driven Formula
Clinically dosed. Purpose-built. Nothing unnecessary.
L-Citrulline — up to 10 g
Powerful pumps & improved endurance
Betaine Anhydrous — up to 5 g
Strength & power output
L-Tyrosine — up to 5 g
Mental drive & focus under stress
Citicoline (CDP-Choline)
Mind-muscle connection & clarity
Acetyl-L-Carnitine
Cognitive performance support
Layered Caffeine System
Fast onset + sustained stimulation
Electrolytes & absorption support
Consistent performance throughout your session
Every ingredient has a function.
Nothing is included for marketing appeal.
Controlled Stimulation
Immediate activation.
Stable energy.
No unnecessary crash.
From first set to final rep — focus stays locked.
Not for Everyone
SENTINEL is not designed for:
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Beginners
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Stimulant-sensitive users
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Recreational or low-intensity training
Looking for a mild daily pre-workout?
This is not it.
Usage
Mix 1 serving (10 g) with 300 ml water.
Take ~20 minutes before training.
Increase only if experienced and well-tolerated.
Do not exceed recommended use.
Product Details
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40 servings
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High-stimulant formula
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Designed for experienced athletes
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Dietary supplement
Why SENTINEL
Most pre-workouts are made to appeal to everyone.
SENTINEL is built to perform.
If you train with intent, SENTINEL delivers the focus and output to match.
Ingredients + Usage
L-Citrulline — 10g
Drives vasodilation, reduces fatigue, improves endurance during high-rep or high-volume sets.
Betaine Anhydrous — 5g
Supports muscular strength and power output. Clinically studied dose.
L-Tyrosine — 5g
Maintains cognitive function and mental drive under physical stress.
Citicoline (CDP-Choline)
Enhances mind-muscle connection and mental clarity throughout the session.
Layered Caffeine System
Fast-acting activation combined with sustained release. No spike, no crash.
Electrolytes + Absorption support
Consistent hydration and nutrient uptake from first set to last.
Mix 1 scoop (10g) with 300ml water, 20 minutes before training. First time? Start with half a scoop. Do not exceed 1 scoop per 24 hours.
Shipping + Returns
Orders are processed within 1–2 business days. Standard delivery within the Netherlands: 1–3 business days. Orders placed before 23:00 are processed the same day.
Free shipping on orders over €50.
Unopened products can be returned within 14 days of delivery. Contact us at info@obsidianperformance.nl to arrange a return.
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OP Sentinel Pre-Workout - Sour Raspberry
€42,95
10g L-Citrulline
5g Betaine Anhydrous
5g L-Tyrosine
Layered Caffeine System
40 Servings Per Container
10g L-Citrulline
5g Betaine Anhydrous
5g L-Tyrosine
Layered Caffeine System
40 Servings Per Container
10g L-Citrulline
5g Betaine Anhydrous
5g L-Tyrosine
Layered Caffeine System
40 Servings Per Container
10g L-Citrulline
5g Betaine Anhydrous
5g L-Tyrosine
Layered Caffeine System
40 Servings Per Container
10g L-Citrulline
5g Betaine Anhydrous
5g L-Tyrosine
Layered Caffeine System
40 Servings Per Container
10g L-Citrulline
5g Betaine Anhydrous
5g L-Tyrosine
Layered Caffeine System
40 Servings Per Container
OP Sentinel vs. Generic Pre-Workouts
Most brands underdose key ingredients and hide behind proprietary blends. Here's the difference.
Order Sentinel
Clinical doses. Full transparency. No shortcuts.
| OP Sentinel | Generic brands | |
|---|---|---|
| Full ingredient transparency (no proprietary blends) | ||
| Clinical dose L-Citrulline (10g) | ||
| Clinical dose Betaine (5g) | ||
| Layered caffeine — no crash | ||
| No artificial dyes or fillers |
THE FORMULA
Clinical doses. Nothing hidden.
Every ingredient in OP Sentinel is listed on the label with its exact dose. No proprietary blends, no filler ingredients dressed up with scientific names.
10g L-Citrulline — maximum pump and endurance
5g Betaine Anhydrous — strength and power output
5g L-Tyrosine — focus under heavy load
Layered caffeine — clean energy, no crash
Why Serious Athletes Choose Sentinel
Straight Answers. No Fluff.
Common questions about OP Sentinel Pre-Workout.
1
What makes OP Sentinel different from other pre-workouts?
Full ingredient transparency — every dose is listed on the label. L-Citrulline at 10g, Betaine at 5g, L-Tyrosine at 5g. These are clinical doses, not marketing doses. No proprietary blends hiding underdosed ingredients.
2
How do I use OP Sentinel?
Mix 1 scoop (10g) with 300ml water, 20 minutes before training. New to high-stim? Start with half a scoop to assess tolerance. Do not exceed one scoop per 24 hours.
3
Is this suitable for beginners?
No — and we're honest about that. OP Sentinel is a high-stimulant product for experienced athletes. If you're new to pre-workouts, start with something milder. If you train seriously and know your stimulant tolerance, this is built for you.
4
Will I crash after using it?
No. The layered caffeine system prevents this. You get fast activation and sustained energy without the sharp drop-off single-source caffeine causes.
5
Does it contain any banned substances?
No. OP Sentinel contains only legal, high-quality ingredients. Full ingredient list is on the label and product page.
6
What is the return policy?
Unopened products can be returned within 14 days of delivery. Opened supplements cannot be returned for hygiene reasons. Email info@obsidianperformance.nl to request a return.