Regular and sustained release arginine fell out of favor and popularity many years ago, so there's not many left that I know of.
It just got to be where brands had next to no demand for it, and brands that did use it were criticized for using it over better ingredients.
I know that on our end, I haven't had a request for arginine in over 10 years.
It first fell out of popularity in pump products in favor of Citrulline Malate and then in favor of L-Citrulline, and in favor of many of the newer more advanced ingredients.
We use Nitrosigine in Super Swole capsules.
Nitrosigine is Inositol Stabilized Arginine Silicate, a clinically researched form of arginine that has been shown to have both immediate and cumulative benefits.
In studies, Nitrosigine was shown to dilate blood vessels up to 500% more than regular arginine. It was shown to increase blood concentrations of arginine for up to 1.5 hours after using it for the very first time. Then it was shown to increase blood arginine levels for up to 6 hours.
That's a big reason we use it in Super Swole caps, because some people use it only for pre-workout purposes, but then many people use it daily for improved muscle fullness and cardiovascular and endothelial health.
I like Nitrosigine much better than regular arginine, but I still think that it works much better in a formulation with other ingredients that target increasing nitric oxide in different pathways. That's why we chose to use it in a formula but never offered it as a single ingredient.
By combining it with Agmatine, you also target increasing nitric oxide levels and inhibiting nitric oxide synthase (the enzyme responsible for nitric oxide breakdown), plus a lot of other overall health benefits. Agmatine's inhibition of nitric oxide synthase is why some people refer to it as a nitric oxide extender because it may prolong the NO boosting effects of other nitric oxide boosters.
Super Swole also contains S7, which is unique and different from arginine and other nitric oxide boosting compounds because it works by helping increase your body's natural levels of nitric oxide production. S7 is included in a lot of pre-workouts and pump products, but I'm much more of a fan of using it in formulas that are daily use formulas because that's how it is going to deliver the best results.
Oh, and Super Swole caps also contain Amentoflavone that helps with pumps and endurance, so it adds a nice touch to the pump benefits from Super Swole and also helps with the endothelial health benefits.
The write up goes into more detail about Nitrosigine and why the different ingredients are used together:
Stimulant Free Pre-Workout & Pump Enhancer. 30 Servings. Convenient Capsule Form. Massive Pumps, Endurance, Improved Performance, & More.
competitiveedgelabs.com
I hope that info helps.