8.1Good
An Informed Sport-certified, vegan pre-workout with 274 mg natural caffeine and 6.5 g citrulline, though its beta-alanine and creatine are under-dosed.
Informed Sport
2 videos$2.25/serving
Transparent Labs Best Overall · Pre-Workout
BULK Pre-Workout
A fully transparent, Informed Choice-certified pre-workout with 8 g citrulline malate, 4 g beta-alanine and a moderate 200 mg of natural caffeine.
8.5
Excellent
Nutrition Reviews score
Weighted across efficacy, quality, value, experience & transparency. See breakdown
- Form
- Powder
- Serving
- 1 full scoop
- Servings
- 30
- Per serving
- $1.67
Informed Choice
Check price on AmazonBuy from the brand$49.99
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Last reviewed September 29, 2026 by the Nutrition Reviews Editorial Team · How we review
Our verdict
BULK is one of the best-formulated and most trustworthy pre-workouts available: clinical doses, published test results and a moderate caffeine load that suits daily training. The stevia-sweetened flavors are its main weakness, so expect a stronger, less candy-like taste than mainstream brands.
Best for
- Daily training with moderate caffeine
- Label-readers who want clinical doses
- Athletes who want a certified product
Skip it if
- Buyers who prioritize candy-like flavor
- Tight budgets
- Stimulant-free users (Transparent Labs sells a separate Stim-Free formula)
How it scored
Our five-factor score out of 10. Factors are weighted by how much they matter to the outcome you’re paying for. Methodology
8.5
Excellentout of 10
- Efficacy30%8.8
Key ingredients at clinically studied doses, and how strong the evidence is.
- Quality & Purity25%9.0
Third-party testing and certifications, manufacturing standards, contaminant testing, recall history.
- Value20%8.0
Cost per effective serving compared with category peers.
- Experience15%7.4
Taste, mixability, texture and tolerability from aggregated buyer and creator feedback.
- Transparency10%9.4
Full label disclosure (no proprietary blends), available COAs, honest marketing.
Our review
Transparent Labs BULK is built for people who read labels. Every one of its 17-plus grams of actives is disclosed, and the core ingredients match or exceed the doses used in research: 8 g of citrulline malate (2:1), 4 g of beta-alanine and 2.5 g of BetaPure betaine, plus 1.3 g of taurine, 1 g of L-tyrosine, 300 mg of AlphaSize alpha-GPC and 200 mg of L-theanine. Caffeine is a moderate 200 mg from organic green coffee beans (PurCaf), backed by 50 mg of theobromine.
That combination covers blood flow, muscular endurance and focus without an extreme stimulant hit, which is why BULK is often recommended as a daily-driver pre-workout. Theanine is a sensible partner for caffeine and may smooth out focus. Less convincing is the "anabolic hormone" framing around boron and zinc: both minerals matter if you are deficient, but evidence that they raise testosterone in healthy, well-fed lifters is weak.
Quality is a genuine strength. Transparent Labs states that BULK is Informed Choice certified and publishes third-party certificates of analysis for purity and potency. It is sweetened with stevia and uses natural flavors rather than sucralose and dyes.
The trade-offs are taste and price. Reviewers on TikTok and YouTube often describe the flavor as strong or hard to drink, and some dilute it with extra water. At $49.99 for 30 servings (about $1.67 each) it costs more than mass-market brands, although the effective doses make the cost per useful serving competitive. The Amazon listing also carries a California Prop 65 warning for lead.
What’s inside
| Key ingredient | Per serving | Why it matters |
|---|---|---|
| L-Citrulline malate (2:1) Provides roughly 5.3 g of L-citrulline, in the range studied for blood flow and training volume. | 8,000 mg | Provides roughly 5.3 g of L-citrulline, in the range studied for blood flow and training volume. |
| Beta-alanine A full dose within the 3.2–6.4 g/day range studied for high-intensity endurance; tingling is common. | 4,000 mg | A full dose within the 3.2–6.4 g/day range studied for high-intensity endurance; tingling is common. |
| BetaPure betaine anhydrous The dose used in most strength and power-output studies. | 2,500 mg | The dose used in most strength and power-output studies. |
| PurCaf organic caffeine A moderate, well-studied dose from green coffee beans, with 50 mg of theobromine alongside. | 200 mg | A moderate, well-studied dose from green coffee beans, with 50 mg of theobromine alongside. |
| L-Theanine Often paired with caffeine to support smoother focus with fewer jitters. | 200 mg | Often paired with caffeine to support smoother focus with fewer jitters. |
| AlphaSize alpha-GPC A choline source studied for focus and power output; evidence is modest. | 300 mg | A choline source studied for focus and power output; evidence is modest. |
Flavors & variants
Blue RaspberryBlack CherryStrawberry KiwiStrawberry LemonadeTropical PunchPeach MangoWatermelonSour Grape
Testing & quality
Publishes third-party batch test results; its grass-fed whey isolate is listed as NSF Certified for Sport, and the brand states Informed Choice and Informed Protein certification.
Goals it supports
Creator video reviews
Independent creators reviewing BULK Pre-Workout on TikTok and YouTube.
4 positive0 mixed1 critical
Pros & cons
What we like
- Clinical doses of citrulline malate (8 g), beta-alanine (4 g) and betaine (2.5 g)
- Moderate 200 mg natural caffeine paired with 200 mg L-theanine
- Informed Choice certified (per the brand) with published third-party COAs
- No artificial sweeteners, colors or preservatives
- Wide flavor range (13 flavors on the brand site)
Watch-outs
- Stevia-sweetened flavors are divisive; several reviewers call it hard to drink
- About $1.67 per serving, more than mass-market pre-workouts
- Boron and zinc "testosterone support" has weak evidence in healthy lifters
- Amazon listing carries a California Prop 65 warning for lead
Questions buyers ask
How much caffeine is in Transparent Labs BULK?
Each scoop has 200 mg of caffeine from organic green coffee beans (PurCaf) plus 50 mg of theobromine. That is a moderate dose compared with 300 mg-plus pre-workouts, which makes BULK easier to use daily. Transparent Labs also sells a Stim-Free formula for people who avoid caffeine entirely.
Is BULK safe for drug-tested athletes?
Transparent Labs states that BULK is Informed Choice certified and publishes third-party certificates of analysis on its website. Informed Choice screens products for banned substances. Tested athletes should still confirm the current listing on the certifier's website and keep a record of the batch they use.
Why does BULK taste different from other pre-workouts?
BULK uses natural flavors and stevia instead of sucralose or artificial dyes, so it tastes less like candy and can have a slightly bitter edge. Reviewers commonly say the flavor is strong. Mixing it with more water, or choosing fruit-forward flavors, is the usual workaround.
Alternatives worth a look
Similar products, ranked by our score.
Legion
Pulse Pre-Workout
8.3Good
Fully dosed and naturally sweetened: 8 g citrulline malate, 3.6 g beta-alanine and a hefty 350 mg of caffeine balanced by 350 mg of L-theanine.
3rd-party testedcGMP
3 videos$2.50/serving
Gorilla Mind
Gorilla Mode Pre-Workout
8.2Good
One of the most heavily dosed pre-workouts: per scoop 5 g citrulline, 2.5 g creatine and 200 mg caffeine, doubling to 400 mg caffeine at the 2-scoop max.
3rd-party tested
3 videos$1.50/serving
8.2Good
A fully disclosed, clinically dosed pre-workout (300 mg caffeine, 6 g citrulline, 3.2 g beta-alanine) wrapped in GHOST's popular licensed candy flavors.
3 videos Shop$1.50/serving
Read the research
Guides 12 min read
How to Read a Supplement Facts Label Like an Expert
Serving sizes, %DV vs. upper limits, ingredient forms, proprietary blends and claims: a step-by-step method for reading any Supplement Facts panel with confidence.
Nutrition Reviews Editorial Team · Sep 28, 2026
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Caffeine dosing by body weight, plus what research says about creatine, beta-alanine, citrulline, nitrates, tyrosine, proprietary blends and stimulant safety.
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Third-Party Testing Explained: NSF vs. Informed Sport vs. USP
What USP, NSF and Informed Sport seals actually test, how to verify a certification in two minutes, how to read a certificate of analysis, and where testing stops.
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