Reading the Research: What the Evidence Says About Popular Supplement Ingredients

Choosing a supplement is easier when you can see what the research actually says — not just what a product label claims. This guide summarizes peer-reviewed, NIH-published research behind several ingredients used across our catalog, so you can weigh the evidence for yourself.

TUDCA (Tauroursodeoxycholic Acid)

TUDCA is a bile acid studied for its role in liver regeneration. A 2025 study published in Biomedicines found that TUDCA promoted liver regeneration and reduced fibrosis in cell culture and animal models by activating a transcription factor called GATA3 — this research has not been conducted in humans. Our TUDCA liver support supplement features 200mg of TUDCA per capsule, paired with Black Pepper Fruit Extract for absorption support; this specific formulation has not itself been clinically tested. Read the full study on TUDCA and liver regeneration.

NMN and Resveratrol for NAD+ Support

NAD+ is a molecule involved in cellular energy metabolism that naturally declines with age. A placebo-controlled clinical trial published in Frontiers in Nutrition found that 250mg/day of oral NMN alone safely raised blood NAD+ levels in healthy adults over 12 weeks, with no reported adverse effects. Our NMN + Resveratrol NAD+ supplement combines 240mg of each per capsule — a different dose and combination than the one studied above, which did not include resveratrol. Read the full NMN safety and NAD+ study.

Yohimbine

Yohimbine is a compound derived from the yohimbe tree, traditionally used as a stimulant and aphrodisiac. According to the NIH’s National Center for Complementary and Integrative Health (NCCIH), there is “not enough evidence for definite conclusions” about yohimbe’s effectiveness for any health condition, and yohimbine has been linked to cardiac arrhythmia, blood pressure changes, and other side effects in some users — which is why it’s restricted or banned in several countries. Our Yohimbine HCL fat burner capsules list the exact dose (5mg/capsule) so you know what you’re taking. Read the NIH NCCIH guide to yohimbe.

Herbal Ingredients for Libido and Testosterone (Tongkat Ali, Tribulus Terrestris, Maca Root)

A systematic review published in Advances in Nutrition examined 32 randomized controlled trials across 13 herbs studied for testosterone support. It found no statistically significant increase in testosterone from Tribulus Terrestris (4 studies), Maca Root (3 studies), or the one included Tongkat Ali study — though the authors noted the research for many herbs remains limited. Our Libido Boost supplement for men combines all three ingredients; these findings apply to the individual ingredients as studied, not to this specific product formulation. Read the full systematic review of herbs and testosterone.

Caffeine

Caffeine is one of the most-studied stimulants available. A comprehensive review published in Frontiers in Psychiatry found that moderate chronic intake up to 400mg/day is not associated with adverse cardiovascular effects in healthy adults, though pregnant women, adolescents, and certain other groups should limit intake further. Our Caffeine Nasal Spray delivers a metered 50mg per spray of caffeine, delivered intranasally rather than the oral intake the review examined. Read the full review of caffeine safety.

A Note on Reading Supplement Research

Evidence quality varies significantly by ingredient — some, like NMN and caffeine, have direct human clinical trial data; others, like several herbal testosterone ingredients, have more limited or mixed findings. None of the studies referenced above tested our specific product formulations directly, and none of this is a guarantee of results. This page is educational and does not replace professional medical advice. Talk to a healthcare provider before starting any new supplement, especially if you take medication or have an existing health condition.