Product Description
Every endurance athlete knows the feeling of oxygen-rich blood reaching working muscles at full capacity — the legs opening up, the lungs finding their rhythm, the effort becoming sustainable...it's smooth.
That experience hinges on nitric oxide, the molecule your blood vessels use to dilate and regulate flow. Your body makes nitric oxide from L-arginine, but the conversion is inefficient without the right cofactors.
Thorne L-Arginine Plus is built for that.
Nitric oxide dilates blood vessels, allowing more oxygen-rich blood to reach working muscles during exercise and supporting faster clearance of metabolic waste products after hard efforts. The downstream effects: improved exercise capacity, shorter recovery, better cardiovascular function.
That's what makes nitric oxide support one of the most well-researched levers in endurance performance nutrition.
Sustained-Release Delivery That Lasts 24 Hours – Most arginine supplements spike and crash within hours — not enough time for meaningful nitric oxide support across a full training day. Thorne's Time-Sorb® sustained-release technology maintains optimal arginine levels continuously when taken twice daily as directed, providing a steady substrate for nitric oxide production around the clock rather than a brief window of elevated levels.
Cofactors That Make the Conversion Actually Work – Arginine alone isn't enough. Nitric oxide synthesis in blood vessels requires specific cofactors, and L-Arginine Plus includes them: vitamin C and methylated folate (5-MTHF) directly support the enzymatic conversion of arginine to nitric oxide, while green tea phytosome, R-lipoic acid, and trans-resveratrol provide antioxidant protection for the vascular endothelium — the lining of your blood vessels where nitric oxide is produced.
Vascular Health Beyond the Workout – L-Arginine Plus supports more than in-session blood flow. By helping maintain healthy vascular elasticity, blood pressure already in the normal range, and the integrity of the vascular endothelium over time, this formula delivers long-term cardiovascular benefits that compound with consistent use — relevant for masters athletes focused on longevity as much as performance.
How to Use Thorne L-Arginine Plus
Daily Dose: Take 3 capsules two times daily, preferably with meals. The twice-daily dosing is what activates the sustained-release delivery — skipping doses breaks the continuous arginine availability the Time-Sorb® system is designed to maintain.
Consistency for Best Results: Like most vascular support supplements, L-Arginine Plus works best with consistent daily use over time. Benefits build as vascular function improves — not a one-session pre-workout product.
- Gluten free
Supplement Facts
60 Servings
Serving Size: Three Capsules
Serving Per Container: 60
| Amount Per Serving | ||
|---|---|---|
| % Daily Value* | ||
| Vitamin C (as Ascorbic Acid) 300mg | ** | |
| Folate (552 mcg as L-5-Methyltetrahydrofolate from L-5-Methyltetrahydrofolic Acid, Glucosamine Salt) 920mcg DFE | ** | |
| L-Arginine 1g | ** | |
| Green Tea Phytosome (Camellia sinensis extract (leaf) / decaffeinated Phospholipid complex from Sunflower) 200mg | ** | |
| R-Lipoic Acid (as Sodium R-Lipoic Acid) 50mg | ** | |
| Trans-Resveratrol 50mg | ** | |
* Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.
** Daily Value (DV) not established
Always Happy Promise: Don't like a product? Tell us within 30 days of receipt and we'll make it right and make you happy. Here at The Feed, we want you to love your experience and the sports nutrition products you purchase. If, for any reason, you are not satisfied with your nutrition specific purchase, tell us.
We do not accept returns on food items that have been opened, but we will issue a store credit if you are unsatisfied. In the event of a return, you must first contact us before sending back a return shipment.
Consumable products over $40 receive a 50% store credit. This includes specialty nutrition products such as ketones or supplements/vitamins.
Thorne L-Arginine Plus FAQ's
Everything you need to know before getting started.
Nitric oxide is the molecule your blood vessels use to relax and dilate — allowing more oxygen-rich blood to reach your working muscles during exercise. Higher nitric oxide availability means better oxygen delivery, improved exercise capacity, and more efficient clearance of metabolic byproducts after hard efforts. Your body produces nitric oxide from L-arginine, which is why arginine supplementation is a well-researched approach to vascular performance support.
Two things. First, the Time-Sorb® sustained-release system maintains arginine levels continuously across 24 hours when taken twice daily — unlike standard arginine supplements that spike and fade within hours. Second, most arginine supplements deliver arginine alone without the cofactors required for efficient nitric oxide synthesis. L-Arginine Plus adds vitamin C, methylated folate (5-MTHF), green tea phytosome, R-lipoic acid, and trans-resveratrol — nutrients that directly support the enzymatic conversion of arginine to nitric oxide and protect vascular tissue in the process.
Vascular benefits from sustained arginine supplementation build over consistent use. Most athletes notice meaningful improvements in cardiovascular function, exercise capacity, and blood pressure support after 2–4 weeks of daily use. This is not an acute pre-workout product — it's a foundational cardiovascular supplement that rewards consistency.
The vascular endothelium — the thin lining of your blood vessels where nitric oxide is produced — is particularly vulnerable to oxidative damage. Green tea phytosome, R-lipoic acid, and trans-resveratrol (the plant compound associated with red wine's cardiovascular benefits) protect endothelial cells from oxidative stress, helping maintain the vessel health that makes efficient nitric oxide production possible over the long term.