Caffeine + Synephrine - GymBeam

Caffeine + Synephrine by GymBeam is a two-ingredient dietary supplement in capsule form. One capsule contains 200 mg of caffeine and 20 mg of synephrine from bitter orange (Citrus aurantium) extract at a 100:1 ratio, standardized to 96% synephrine.

What do these numbers mean in practice? The 100:1 ratio means that one gram of extract is made from 100 grams of dried raw material. Standardization to 96% means that synephrine itself accounts for 96% of the extract’s weight. To obtain 20 mg of synephrine, you therefore need approximately 20.8 mg of extract—and that 20.8 mg of extract comes from 2.08 grams of dried bitter orange peel.

These are verifiable figures, not marketing claims. You can calculate them yourself using the information on the label. That is precisely what sets this product apart from those that list only “bitter orange extract” without specifying a ratio or standardization.

Pre-workout supplements are most commonly sold as powder in a tub with a scoop. That sounds more convenient than it actually is.

A scoop is not precise. The powder settles during transport, it packs differently at the beginning and end of the tub, and the difference between a level and a heaped scoop can be tens of percent. When the difference between 150 and 250 mg of an ingredient is noticeable, that matters. Each capsule is measured during production. Take one and you get exactly 200 mg of caffeine and 20 mg of synephrine. The same amount every time. No weighing, no scoop, no guesswork.

There is also portability. Ninety capsules fit in a pocket of your gym bag. You would not take a tub of powder and a scoop on a business trip or holiday. And one more thing: a capsule has no taste. You do not have to worry about whether you like the flavour, whether the powder dissolves well, or whether it leaves sediment at the bottom of your shaker.

Caffeine is an alkaloid that occurs naturally in more than sixty plants, including coffee plants, tea plants, cacao and guarana. It is the most extensively studied active substance in the human diet.

The scale of the research can be expressed in a single number. A review in the British Journal of Sports Medicine examined not individual studies but the meta-analyses themselves, and found twenty-one of them.⁵ Most ingredients in dietary supplements do not have even one. According to this review, caffeine was ergogenic—that is, it improved performance—in endurance, strength, muscular endurance, power, jumping and movement speed.

One finding challenges a widespread belief: that caffeine no longer works before exercise if you drink coffee every day. A meta-analysis in Sports Medicine tested this claim and did not confirm it: habitual coffee consumption does not eliminate caffeine’s ergogenic effect.⁶ People do, however, respond to caffeine differently, and this is not a matter of psychology: variants of the CYP1A2 gene, which encodes the enzyme responsible for most caffeine metabolism, play a decisive role.⁷ That is why one person can sleep after two coffees, while another cannot fall asleep after one in the afternoon.

This leads to the most practical rule. Caffeine has an elimination half-life of approximately five hours.¹ If you take a capsule at four in the afternoon, you will still have roughly 76 mg in your body at eleven that night—about the amount in a cup of coffee. Therefore, take it in the morning or before training, never in the afternoon.

Safety framework. EFSA states that single doses of up to 200 mg do not raise safety concerns for healthy adults, even when taken two hours before intense physical activity; it gives a reference value of 400 mg for daily intake.¹ The capsule is at the upper limit for a single dose and half the daily reference value.

Synephrine is an alkaloid found in citrus peel. Its richest source is the bitter orange, the same fruit used to make English marmalade. Supplements use p-synephrine, the form that also occurs naturally in citrus fruits.

Research on this substance has been conducted primarily by one Spanish group, whose studies share a methodology: double-blind crossover designs with measurements of respiratory gas exchange. An initial study in 2016 found that p-synephrine increased the maximum rate of fat oxidation by 0.11 g/min, which the authors calculated as approximately seven additional grams of fat per hour of exercise, at the same intensity and the same heart rate.⁸ That last point matters more than the number itself: the participants did not exercise harder; their bodies simply used a different fuel.

A dose-dependent study from 2018 added to these findings. Seventeen volunteers completed four trials with a placebo or 1, 2 or 3 mg per kilogram. Maximum fat oxidation rose from 0.35 to 0.55 g/min at doses of 2 and 3 mg/kg. None of the doses affected heart rate or energy expenditure.⁹

However, the same group also published a study in 2022 involving healthy, active women and found no effect.¹⁰ This finding belongs in the picture just as much as the positive results.

One point should be made clear. Those studies used 2 to 3 mg per kilogram, which amounts to 140 to 210 mg for a person weighing seventy kilograms. A capsule contains 20 mg. The 1 mg/kg dose, or 70 mg, did not reach statistical significance.⁹ This is not a formulation error: France permits a maximum of 20 mg of synephrine in a supplement, and limits in other markets are similar. The doses studied could not be marketed in the EU.

The laboratory did not detect any of the heavy metals tested at levels above the limit of quantification.² These are not values just below the limit; they are values the instrument could not detect. The sample complies with Regulation (EU) 2023/915³ on maximum levels for contaminants in food.

The microbiological testing panel is also more comprehensive than standard testing: in addition to Salmonella, it tests for yeasts, moulds and coliform bacteria—three parameters monitored in plant extracts precisely because the raw material is dried plant matter.