Non Stim Pre Workout: 7 Proven Facts and Limits

A non stim pre workout in three numbers

Three numbers frame what a stim free pre workout can do. How big the main pump effect is, how long the strength ingredients need, and why people drop caffeine in the first place.

Every figure on this page comes from a PubMed abstract, the FDA or the product listing named in the sources. Effect size labels like small and medium are a rule of thumb. Doses are study facts, not advice.

What this guide covers

What is left in a pre workout without caffeine?

In a normal pre workout, caffeine does most of what you feel. The ISSN position stand says it improves endurance, strength, power, sprinting and jumping in many studies. The usual dose is 3 to 6 mg per kg of body weight, about 60 minutes before exercise (PMID 33388079).

Caffeine also helps attention and alertness in most people (PMID 33388079). No other common pre workout ingredient does all of this from one dose.

Take caffeine out, as a non stim pre workout does, and the rest of the formula splits into two groups. Some ingredients act on the day you take them. Others only work when you take them every day for weeks.

Citrulline, nitrate and glycerol: the pump ingredients

These are the non stim pre workout ingredients that act on the day. They aim to widen blood vessels or hold more water in the body.

Citrulline

A 2019 review pooled 12 studies with 198 people. Citrulline gave a small benefit for high intensity strength and power, with an effect size of 0.20. It only counted doses of 3 g or more, taken at least 30 minutes before exercise (PMID 30895562).

The best known trial gave 41 men 8 g of citrulline malate before chest training. In the last bench press set they did 52.92 percent more reps, and soreness was 40 percent lower over the next two days. About 15 percent had stomach discomfort (PMID 20386132).

A wider 2020 review was more careful. It found that proof of better blood flow after citrulline is scarce and inconsistent, even though some studies show better performance (PMID 31977835).

Nitrate

A 2020 review of 80 studies found a clear but small effect of nitrate, 0.174. The effect did not show in studies with only women, or in very fit endurance athletes (PMID 32936597).

A 2022 review of 123 studies found an even smaller overall effect, 0.101. Nitrate salts worked less well than beetroot juice. The best single dose was 5 to 14.9 mmol, taken at least 150 minutes before exercise. Efforts of 2 to 10 minutes gained the most (PMID 35580578).

Nitrosigine

In a trial of 24 young adults, 1.5 g of Nitrosigine raised blood vessel widening by 31 percent an hour later. 8 g of citrulline malate raised it by 34 percent (PMID 32093766). That trial measured blood vessels, not reps or strength.

Glycerol

Glycerol helps the body hold extra water. The studied protocol is 1.2 g per kg of body weight in 26 mL of fluid per kg, over 60 minutes. Side effects were rare but included nausea, stomach upset and light headedness (PMID 20092365).

Betaine, creatine and beta alanine: they work, but not from one scoop

Three of the most useful ingredients in a non stim pre workout have nothing to do with the hour before training. They build up in muscle over days or weeks.

Betaine. A 2024 review of 17 studies found a medium sized benefit for maximal strength, 0.47, mainly in the legs. Everyone took betaine for at least 7 days (PMID 39514262). See our full guide to betaine anhydrous.

Creatine. In a classic study, 3 g a day for 28 days raised muscle creatine by about 20 percent. When people stopped, levels fell back to baseline within 30 days (PMID 8828669). More in our creatine loading phase guide.

Beta alanine. The ISSN says 4 to 6 g a day for at least 2 to 4 weeks. It helps most in efforts of 1 to 4 minutes. The only side effect is tingling, which smaller split doses of 1.6 g can reduce (PMID 26175657).

What replaces caffeine for focus in a non stim pre workout?

Nothing in a non stim pre workout matches caffeine for alertness. Two ingredients have some support.

Tyrosine. A 2015 review found it helps thinking mainly in short, stressful or very demanding situations. Its use for physical exercise looked minimal (PMID 26424423). A normal gym session after a normal day is not that kind of stress.

Alpha GPC. In 13 college men, 600 mg a day for 6 days raised force in a mid thigh pull compared with placebo. The upper body test did not change significantly (PMID 26582972). That is one small study.

Who a caffeine free pre workout suits

The best reason to go stim free is sleep. In a home study, 400 mg of caffeine at bedtime, 3 hours before or 6 hours before bed all disturbed sleep against placebo. The authors said caffeine 6 hours before bed has important effects on sleep (PMID 24235903).

Evening lifters. If you train within about 6 hours of bed, a non stim pre workout avoids trading sleep for one session.

People near their caffeine limit. The FDA cites 400 mg a day as an amount not generally linked to negative effects. A 12 ounce brewed coffee carries about 113 to 247 mg (FDA). Coffee plus a stimulant pre workout can pass that fast. See caffeine in Monster Energy for drinks.

Caffeine sensitive people. Anxiety and poor sleep after caffeine vary a lot between people, partly because of genes (PMID 33388079).

People who want control. A stim free base plus your own coffee lets you set the caffeine dose yourself.

Reading a stim free pre workout label against the research

As an example we read Gorilla Mode Nitric, a caffeine free pre workout from Gorilla Mind. Figures are label claims for the full two scoop serving, from the product listing in October 2026. We did not lab test it. For the stimulant version, see our Gorilla Mode pre workout review.

The nitrate figure is our own calculation from the salt: 1.5 g of sodium nitrate holds about 1.1 g of nitrate. The brand itself says over a gram. A 2022 review found nitrate salts worked less well than beetroot juice (PMID 35580578).

The directions say 1 to 2 scoops 30 minutes before training, no more than 2 scoops in 24 hours. The listing warns against use with PDE5 inhibitors, nitrites or blood pressure lowering drugs or supplements.

Seven proven facts about non stim pre workout formulas

1. Caffeine is the best supported ingredient you remove. It helps endurance, strength, power and attention from one dose (PMID 33388079).

2. Citrulline has a small, real effect. Effect size 0.20 in 12 studies (PMID 30895562).

3. Nitrate effects are small and timing matters. Best at 2.5 hours or more before exercise (PMID 35580578).

4. Betaine, creatine and beta alanine need daily use. From 7 days to 4 weeks (PMID 39514262, PMID 8828669, PMID 26175657).

5. Glycerol is almost always far below the studied dose. 1.2 g per kg with lots of fluid (PMID 20092365).

6. Focus ingredients are situational. Tyrosine helps mainly under acute stress (PMID 26424423).

7. Late caffeine costs sleep. 400 mg 6 hours before bed still disturbed sleep (PMID 24235903).

So, do non stim pre workouts work?

Partly. A well dosed non stim pre workout gives a small boost from citrulline (PMID 30895562) and maybe a small one from nitrate (PMID 32936597). It also gives useful doses of creatine, betaine and beta alanine, if you take it every day.

It makes sense if: you train in the evening, caffeine gives you anxiety or bad sleep, or you already drink a lot of coffee.

Skip it if: you expect energy or focus from it, or the label hides doses in a proprietary blend. A morning lifter who handles caffeine well may also prefer a stimulant formula.

Our take, as a rule of thumb: plain citrulline before training plus daily creatine covers the core of the research for less money. A finished non stim pre workout is worth it when the doses match and you value the convenience. More guides sit on the supplements hub and in performance supplements.