Rule One Citrulline is a simple L-citrulline supplement that helps nitric oxide production, so you can enjoy stronger muscle pumps and longer endurance during workouts. The star ingredient remains L-citrulline, and Rule One is known for clean, single ingredient formulas and high quality standards. It works as a straightforward option for athletes who want dependable pre workout support.

Available Sizes & Variants:

198 grams Rule One Citrulline - Unflavoured powder designed for easy mixing with other pre workout drinks.

Benefits & Features:

• A natural boost to nitric oxide production supports improved muscle pumps during workouts and complements a best protein powder routine.
• Supports training endurance by improving blood flow, and pairs well with creatine in pre workout stacks to help you push through tougher sets.
• Unflavoured powder integrates easily into any pre workout drink, with no aftertaste.
• Designed for daily use by athletes, the formula delivers 3.3 grams of L-citrulline per scoop, supporting nitric oxide pathways that help you train harder and recover more effectively between sessions over time.
• L-citrulline stands out as the star ingredient driving the key benefit.

Rule One Citrulline is unflavoured and simple to drop into any workout routine, mixing easily with your chosen drink. The star ingredient, L-citrulline, drives nitric oxide production to support better pumps and endurance. Rule One is proud of clean, single ingredient formulations and rigorous batch testing that shines through in quality. This straightforward formula fits athletes who want dependable, stackable support, whether you are pairing with creatine and a best protein powder or weaving in probiotics for overall wellness. Quality you can trust.

L-Citrulline, L-Citrulline

• GTIN: 196671004635
• Manufacturer: Rule One
• Categories: Citrulline SupplementsNitric Oxide Boosters SupplementsRule OneStamina & Endurance Supplements
• Best buy: 6 - 24 months+

United Kingdom Shipping:

Orders placed by 2pm (Monday to Friday) are dispatched the same day. Orders placed after 2pm will be dispatched the next working day.

Free shipping on orders over £50 to the UK.

Returns: Our products are meant to make you feel healthy and at your best. If you need to return your item, you can do so free of charge within 30 days in the same original and unopened packaging. Subject to T&C's.

Mix one scoop (3.3g) with 8-12 oz. of any cold beverage or liquid workout supplement. Consume before or during workouts. Combine with a balanced diet and regular exercise. Store this container tightly closed in a cool and dry place. Keep out of reach of children. For use by healthy active adults only. Consult your physician before using this product if you are taking any medication, are under a physician's care for any medical condition, or are under 18 years of age. Not for use by women that are pregnant, trying to get pregnant, or nursing.

Please consult the product packaging for accurate instructions on how to use the product.

*Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

The Active Ingredient Is: L-citrulline

L-citrulline is an amino acid that helps produce nitric oxide, supporting steady blood flow to muscles during activity. This form is plain unscented L-citrulline powder, designed as a single-ingredient formula for clean supplementation.

This product yields plain L-citrulline without flavourings or fillers, offering a straightforward ingredient profile that lines up with single-ingredient quality standards.

What Does L-citrulline Do?

L-citrulline participates in nitric oxide synthesis, which can help support blood flow to working muscles and improve endurance during exercise. Studies note potential improvements in muscle pumps and training efficiency when used before activity.

In line with common nutritional guidance, this ingredient helps normal physiological processes involved in exercise performance and muscle function.

*This product is not intended to diagnose, treat, cure, or prevent any disease.

Welzo teams up with brands that show real commitment to purity, reliability and scientific rigour. Rule One really shines for its reputation as a clean, single ingredient expert, celebrated for pure L-citrulline and top quality standards. This brand has earned trust in the sector through a razor-focused approach to formulation, matching our emphasis on simple, well-sourced supplements. Our evaluation process includes a thoughtful review by our expert team of doctors, nurses, and nutritionists to ensure it aligns with Welzo’s criteria and consumer safety expectations, while continually referencing our supplement quality standards.
Rule One's focus on purity and a single active ingredient makes it a perfect match for this citrate product, which is meant to be mixed with drinks and used as part of a pre-workout routine.