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Transparent Labs Stim-Free Pre-Workout Review

8.5 Formula Score
Updated April 2026
By Duc Nguyen
Bottom Line
Transparent Labs Stim-Free is the pre-workout for people who want the pump, the focus, and the performance ingredients without any caffeine. The ingredient profile is excellent and fully disclosed. If you train in the afternoon or evening or just want to control your caffeine separately, this is one of the best options available.

Why Go Stim-Free

A lot of people want the performance benefits of a pre-workout but either cannot tolerate caffeine, train at times when caffeine would disrupt sleep, or already get plenty of caffeine from other sources throughout the day. A stimulant-free pre-workout addresses all of those situations without sacrificing the ingredients that actually improve your workout performance.

Transparent Labs built their stim-free formula specifically to give you everything that works in a pre-workout except the caffeine. The result is a product with a very impressive ingredient profile that stands on its own merits.

What Is Actually in It

You get 8 grams of citrulline malate for blood flow and pump, 4 grams of beta-alanine for muscular endurance, 2.5 grams of betaine, and 1.3 grams of taurine for focus and hydration. These are clinical doses across the board. Transparent Labs takes the same approach as Legion when it comes to label transparency, meaning every ingredient is fully disclosed with no proprietary blending.

The focus component in a stim-free product comes primarily from taurine and other nootropic ingredients rather than caffeine. It is a different kind of focus than the caffeine-driven alertness you might be used to, but it is real and it works well.

How It Performs

The pump from the citrulline malate at 8 grams is excellent. I notice a meaningful difference in vascularity and muscle fullness during workouts when using this versus training without any pre-workout. The endurance benefit from beta-alanine at 4 grams is also real over time, though like all beta-alanine it requires consistent use to fully experience.

The absence of caffeine means the onset is less dramatic than a stimulant-based pre-workout. There is no buzz, no tingles from caffeine. What you get instead is a steady, sustainable performance boost that does not come with any crash afterward.

Best Use Cases

This is ideal for evening workouts, for people who are already consuming caffeine from coffee or other sources throughout the day, for athletes who want to stack it with their own caffeine source to control the dose precisely, or for anyone who has had bad experiences with high-caffeine pre-workouts in the past.

Caffeine0mg (Stim-Free)
Citrulline Malate8g
Beta-Alanine4g
Betaine2.5g
Taurine1.3g
Proprietary BlendNone
Servings30
Price per Serving~$1.67
What I Like
  • No caffeine, perfect for evening workouts
  • Clinically dosed and fully transparent label
  • Excellent pump from full-dose citrulline
  • More servings per container than stimulant version
  • No crash or sleep disruption
  • Can be stacked with your own caffeine source
Worth Knowing
  • Less dramatic initial feeling without caffeine stimulation
  • Beta-alanine tingling still present
  • Slightly earthy taste from some ingredients
  • Some people find it less motivating without caffeine
  • Requires adjusting expectations from stimulant pre-workouts
Transparent Labs Stim-Free Pre-Workout
Best Stim-Free Pre-Workout · Formula Score 8.5
$49.99 / 1.34 lbs · 30 servings
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