About the Product
Marvelous Nutrition's Testo is a plant-extract based testosterone booster in HPMC capsules, formulated with 6 exclusively plant-derived active ingredients in clinical doses per serving (3 capsules): Tribulus terrestris 600mg (the classic natural testosterone booster), Fenugreek 375mg (supports free testosterone by inhibiting SHBG), Maca 375mg (Andean adaptogen for vitality and libido), Ashwagandha 375mg (cortisol reducer and HPA-gonadal axis support), Oat Extract 225mg (avenacoside, releases SHBG-bound testosterone) and Saw Palmetto 150mg (supports prostate health and inhibits 5-alpha-reductase). A food supplement with 100% plant-based capsules (HPMC), vegan — distinguishing itself from Testoman (which uses bovine gelatin capsules). 90 capsules, 30 servings. Take 3 capsules before training. Vegan.
Benefits
TESTO vs. TESTOMAN: two testosterone boosters with distinct philosophies:
The Marvelous portfolio features two testosterone boosters with complementary approaches. Testoman (Marvelous Line, bovine gelatin capsules) combines plant ingredients with minerals (zinc, magnesium), L-Carnitine L-Tartrate, and vitamins (B6, D3) in a more comprehensive formula. Testo (Loaded Ingredients, vegan HPMC capsules) is a formula exclusively based on botanical extracts in higher doses per ingredient — 600mg of Tribulus vs. a smaller dose in Testoman, 375mg of Ashwagandha vs. Testoman's 5:1 version. Testo is the choice for vegan athletes or for those who prefer a 100% botanical formula without added minerals or animal-derived ingredients.
Tribulus terrestris 600mg (whole plant): the most documented LH stimulator and testosterone support:
Tribulus terrestris is the plant with the longest history of use as a natural testosterone booster and one of the most widely studied in this context. It contains steroidal saponins (protodioscin, dioscin, tigogenin) which, according to the most established hypothesis, stimulate the release of LH (Luteinizing Hormone) by the anterior pituitary gland, which in turn stimulates the Leydig cells of the testes to produce testosterone. The whole plant extract used in Testo includes both aerial parts and roots, covering the full spectrum of the plant's saponins. The dose of 600mg per serving is one of the highest available in natural testosterone boosters, superior to most products on the market (which typically use 300 to 500mg). In addition to supporting LH, Tribulus has adaptogenic, aphrodisiac (improving libido and sexual function), and natural anabolic properties documented in multiple clinical trials in men with partial androgen deficiency.
Fenugreek (Trigonella foenum-graecum) 375mg: SHBG inhibition and increased free testosterone:
Fenugreek is a Mediterranean plant whose seeds contain furostanolic saponins (fenuside, trigonelline, diosgenin) with a specific mechanism of action on SHBG (Sex Hormone Binding Globulin) — the plasma transport protein that binds to circulating testosterone, making it biologically inactive (SHBG-bound testosterone cannot activate androgen receptors in target tissues). Fenugreek compounds inhibit SHBG, increasing the proportion of free testosterone (biologically active) without necessarily increasing total testosterone. The clinical trial by Wilborn et al. (2010), published in the International Journal of Sport Nutrition and Exercise Metabolism with 49 men in resistance training for 8 weeks, documented that 500mg/day of fenugreek extract maintained testosterone and dihydrotestosterone levels while the placebo group had a reduction — suggesting an anti-catabolic effect on androgens during intense training.
Maca (Lepidium meyenii) 375mg: the Andean adaptogen for vitality, libido, and performance:
Maca (Lepidium meyenii) is a cruciferous plant from the high altitudes of the Peruvian Andes (3000 to 4500m altitude), with millennial ethnobotanical use among Andean populations as food and a tonic for fertility, energy, and resistance to altitude sickness. Its active components are macamides and macaridine (alkaloids exclusive to maca), glucosinolates (benzyl glucosinolate, p-methoxybenzyl glucosinolate), and plant sterols (β-sitosterol, campesterol). Maca does not directly affect testosterone levels — its mechanism of action is different: it modulates the HPA (hypothalamic-pituitary-adrenal) axis adaptogenically, reducing cortisol and improving resilience to stress, which indirectly favors testosterone production (cortisol competes with testosterone for the common precursor pregnenolone). Clinical trials with maca consistently document improved libido, sexual function, and well-being in men and women, with less evidence of a direct effect on serum testosterone. The 10:1 extract indicates a high concentration (10kg of fresh root per kg of extract).
Ashwagandha (Withania somnifera) 375mg: the anti-cortisol adaptogen and direct support for the HPA-gonadal axis:
As already described in detail in the Escape, Alive, and Amputation sections, Ashwagandha has the most robust evidence base of all adaptogens for cortisol reduction and testosterone support. The cortisol-testosterone link mechanism is direct: cortisol and testosterone are both produced from cholesterol via pregnenolone (the common precursor of all sex steroids and cortisol). When the HPA axis is chronically activated (by physical stress from intensive training or psychological stress), pregnenolone is preferentially channeled into cortisol production (by 21-hydroxylase in the adrenal gland) at the expense of testosterone (by 17-hydroxylase/17,20-lyase in the testes) — a phenomenon known as "cortisol steal" or "pregnenolone steal". Ashwagandha's reduction of cortisol frees up pregnenolone for testosterone synthesis, increasing testosterone levels. The clinical trial by Wankhede et al. (2015), published in the Journal of the International Society of Sports Nutrition with 57 men in resistance training, documented that 300mg/day of KSM-66 Ashwagandha for 8 weeks increased serum testosterone by 15.0% and serum cortisol decreased by 11.0% vs. placebo.
Oat Extract (Avena sativa) 225mg: avenacoside as a releaser of SHBG-bound testosterone:
Oat seed extract is standardized in avenacoside (steroidal saponins from oats), which inhibit SHBG similarly to fenugreek but with a slightly different mechanism — avenacosides directly compete with androgens for SHBG binding sites, "freeing up" testosterone that was bound and making it biologically active. Oats are also rich in beta-glucan (soluble fiber with effects on cholesterol — the precursor to testosterone) and magnesium (which, as described, is essential for Leydig cell function). The combination of Oat Extract + Fenugreek in Testo covers two distinct pathways for releasing biologically active testosterone: competition with SHBG (avenacoside) and inhibition of SHBG (fenugreek saponins).
Saw Palmetto (Serenoa repens) 150mg: prostate health and 5-alpha-reductase inhibition:
Saw Palmetto (Serenoa repens) is the most studied plant extract for prostate health and the most prescribed in Europe for benign prostatic hyperplasia (BPH). Its relevant mechanism of action in a testosterone booster is the inhibition of 5-alpha-reductase — the enzyme that converts testosterone into DHT (dihydrotestosterone), the androgen 5 to 10 times more potent than testosterone but also primarily responsible for benign prostate hypertrophy and androgenic alopecia. By inhibiting 5-alpha-reductase, Saw Palmetto: reduces DHT levels in the prostate (protecting it from hypertrophy), preserves testosterone levels (which would otherwise be converted to DHT), and can reduce androgenic hair loss. The inclusion of Saw Palmetto in Testo is a preventative health addition that distinguishes this booster from products that simply maximize testosterone/DHT without considering the potential negative effects of excess DHT on the prostate and scalp.
Usage
Recommended dose: Take 3 capsules before training. For daily hormonal support (independent of training), take 3 capsules in the morning with breakfast. Use in cycles: 8 weeks on + 4 weeks off to maintain receptor sensitivity and prevent desensitization of the HPA-gonadal axis. 90 capsules = 30 servings.
