Table 3.

Studies included in the systematic review of the effect of Tribulus terrestris L. on hematological and biochemical markers, hormonal behavior, and oxidant response in healthy adults.

First Author, Year of Publication, and Country	Study Design	Participants (Baseline Sample Size and Characteristics, Withdrawals, and Final Group Sample Size)	Intervention	Outcomes	Results
Ma et al., 2017, China [12]	Random-ized, double-blind, placebo-controlled trial	15 boxers (national second-level athletes, 2–3 y of training) Age (mean ± SD): CG: 16.6 ± 1.9 y IG: 16.1 ± 1.8 y Weight (mean ± SD): CG: 62.8 ± 15.2 kg IG: 64.1 ± 6.6 kg Body fat (mean ± SD): CG: 9.6 ± 3.2% IG: 9.8 ± 2.4% 2 withdrawals/lost to follow-up 13 participants completed the study 7 participants CG 6 participants IG	2 × 625 mg TT (Pronova Biocare, Sweden) (>40% steroidal saponins) “Placebo” (starch) 2 cap every morning 3 wk supplementation For high-volume training 4 wk rest 3 wk supplementation For high-intensity training	BUN CK DHT T IGF-1 IGFBP-3	IG vs. CG
					high-volume training	high-intensity training
					↓BUN ↑CK ↓DHT ↓Testosterone ↓IGF-1 ↓*IGFBP-3	↓BUN ↓*CK ↓DHT ↓Testosterone ↑IGF-1 ↓*IGFBP-3
					IG: change from baseline
					high-volume training	high-intensity training
					↑BUN ↑CK ↓DHT ↑Testosterone ↓IGF-1 ↓*IGFBP-3	BUN ↓*CK ↓DHT ↑Testosterone ↓IGF-1 ↓*IGFBP-3
Rogerson et al., 2007, Australia [14]	Random-ized, double-blind, placebo-controlled trial	22 male elite rugby players Age (mean ± SD) CG: 19 ± 1.3 y IG: 20.5 ± 3.8 y Weight (mean ± SD) CG: 87.6 ± 9.0 kg IG: 88.5 ± 10.5 kg No withdrawals reported 11 participants CG 11 participants IG	450 mg/cap of TT extract (Body Science, Sydney, Australia) (60% steroidal saponins; 40% flavonoids, alkaloids, phenols). “Placebo” inert herbs identical TT 1 cap × day 5 wk	Testosterone/Epites-tosterone	IG vs. CG ↓Testosterone/Epitestosterone IG: Change from baseline ↓Testosterone/Epitestosterone
Fernández-Lázaro et al., 2021, Spain [15]	Random-ized, single-blind, placebo-controlled trial	30 CrossFit®-trained athletes Age (mean ± SD): CG: 33.1 ± 5.7 y IG: 32.9 ± 6.3 y Body mass (mean ± SD) CG: 80.1 ± 10.7 kg IG: 81.2 ± 11.5 kg No withdrawals reported 15 participants CG 15 participants IG	2 caps × 385 mg TT (Quamtrax Europe, Spain) (40% steroidal saponins) “Placebo” (maltodextrin) 2 caps empty stomach 6 wk	Testosterone Cortisol Testosterone/Cortisol	IG vs. CG ↑*Testosterone ↓Cortisol ↑Testosterone/Cortisol IG: Change from baseline Testosterone ↓Cortisol ↑Testosterone/Cortisol
Talemi et al., 2021, Iran [17]	Random-ized, double-blind, placebo-controlled trial	18 healthy physically active through resistance exercise training Age (mean ± SD) 22.44 ± 2.54 y BMI (mean ± SD) 26.15 ± 1.62 kg/m2 No withdrawals reported 9 participants CG 9 participants IG	2 × 250 mg TT TT powder and extract (27 mg total phenolic content, 100 mg furostanol saponins, and 34 mg total flavonoids) “Placebo” (maltodextrin) 2 wk daily: morning and evening intakes after meal	IL-6 Hs-CRP CK LDH	IG vs. CG ↓IL-6 ↓Hs-CRP ↓CK ↓*LDH IG: Change from baseline ↑*IL-6 ↑Hs-CRP ↓CK ↑LDH
Milasius, et al., 2019, Lithuania [22]	Placebo-controlled study	32 athletes’ endurance sport Age (range): 20-22 y Weight (mean ± SD): CG 76.0 ± 8.2 kg IG 75.3 ± 7.7 kg BMI (mean ± SD) CG: 22.9 ± 1.7 kg/m2 IG: 23.1 ± 1.9 kg/m2 No withdrawals reported 12 participants CG 20 participants IG	3 × 625 mg TT powder (Optimum Nutrition, EE.UU.) (100% furostanol saponins) a.m. (1 × cap) and p.m. (2 × caps) intakes 20 days	RCB Hb HCT MVC ERS WBC LYM MON GRAN CK Cr Ua Urea Chol Tg Bilirubin Testosterone Cortisol	IG vs. CG ↓RCB ↑HB ↑HCT ↓MVC ↑ERS ↓WBC ↓LYM ↑MON ↑GRAN ↑*CK ↓Cr ↑Ua ↓Urea ↓Chol ↑Tg ↓Bilirubin xTestosterone xCortisol	IG: Change from baseline ↓RCB ↓HB ↑HCT MVC ↓ERS WBC ↓*LYM ↓MON ↑*GRAN ↑*CK ↓Cr ↓Ua ↓Urea ↓Chol ↑Tg ↓Bilirubin ↑Testosterone ↑Cortisol
Poprzecki et al., 2005, Poland [23]	Placebo-controlled study	24 competitive basketball players Age (mean ± SD): 26 ± 3.4 y Weight (mean ± SD): 91.5 ± 9.0 kg No withdrawals reported 8 participants CG 8 participants IG	“Tribusteron 90” 450 mg/cap (100% Steroidal saponins) 1st 4 caps × day, 2 wk (1800 mg saponins) 2st 6 caps × day, 2 wk (2700 mg saponins) “Placebo” 450 mg/caps gelatin. Twice daily: 30 min before training and 20 min before going to bed 4 wk	Testosterone Luteinizing Hormone Estradiol	IG vs. CG ↓Testosterone ↑Luteinizing Hormone ↑Estradiol IG: Change from baseline ↓*Testosterone ↑Luteinizing Hormone ↑*Estradiol
Wilk et al., 2012, Poland [24]	Random-ized, placebo-controlled trial	14 with 4 training sessions * wk, (2 sessions anaerobic power, 2 of aerobic endurance exercise) Age (range): 45–60 y BMI (range): 25–30 kg/m2 Body fat (range): 23–30% No withdrawals/lost to follow-up reported	1st 6 wk: 900 mg TT (100% steroidal saponins) 2 caps × 300 mg morning on an empty stomach 1 cap × 300 mg bedtime 2nd 6 wk: 1800 mg TT (100% steroidal saponins) 4 caps × 300 mg morning on an empty stomach 2 caps × 300 mg bedtime “Placebo” caps gelatin 12 wk	Chol LDH-Chol HDL-Chol GH IGF-1 Testosterone	IG vs. CG ↓*Chol ↑*HDL-Chol ↓*LDH-Chol ↑*GH ↑*IGF-1 ↑*Testosterone IG: Change from baseline ↓*Chol ↑*HDL-Chol ↓*LDH-Chol ↑*GH ↑*IGF-1 ↑*Testosterone

Abbreviations: ↑ = no significant increase; ↓ = no significant decrease; = no significant change. ↑* = significant increase; ↓* = significant decrease; CG = control group; IG = intervention group; wk = weeks; caps = capsules; TT = Tribulus Terrestris; DHT = dihydrotestosterone; IGF-1 = Insulin-like growth factor 1; IGFBP-3 = Insulin-like growth factor binding protein 3; GH = growth hormone; CK = creatine kinase; LDH = lactate dehydrogenase; Cr = creatinine; Ua = uric acid; BUN = blood urine nitrogen; RCB = red blood cells; HB = Hemoglobin; HCT = Hematocrit; ESR = erythrocyte sedimentation rate; MCV = mean corpuscular volume; WBC = white blood cells; LYM = lymphocytes MON = monocytes; GRAN = granulocytes; Chol = cholesterol; Tg = triglycerides; LDH-Chol = low-density lipoprotein; = males; HDL-Chol = high-density lipoprotein; IL-6 = interleukin 6; Hs-CRP = high-sensitivity C-reactive protein; y = years; kg = kilograms; m² = square meters; mg = milligrams.