Benefits
Lower body strength improvement
In a manufacturer-funded trial of 99 young men (average age 22) doing resistance training three times a week, the blend improved 1-RM strength more than exercise alone; the 850 mg group gained about 13.8 kg more on the bench press than placebo at 8 weeks. The 4.2x figure and any result in older adults are not found in any published study.
Grip strength and muscle endurance
In young men doing resistance training, the blend increased repetitions to failure beyond exercise alone. The 4.5x grip strength and 1.5x endurance numbers do not appear in any published trial, and no study has tested grip strength, fall prevention, or functional independence in older adults.
Walking capacity and functional mobility
No published study has measured walking capacity or the 6-minute walk test for this blend. The 90% figure does not appear in any peer-reviewed trial and cannot be verified.
mTOR activation and muscle protein synthesis
Laboratory work has proposed several mechanisms for the blend, including mTOR pathway activity, reduced muscle protein breakdown, better mitochondrial efficiency, and nitric oxide support. These are proposed pathways only; they have not been directly demonstrated in people taking the supplement, and none have been studied in older adults.
Mechanism of action
Mitochondrial efficiency enhancement
Strengthera's primary proposed mechanism is enhancement of mitochondrial energy metabolism efficiency in muscle tissue, making the same amount of exercise more productive and allowing muscle cells to generate more force per ATP consumed.
mTOR pathway activation
The botanical combination is proposed to act on mTOR (mechanistic target of rapamycin), a key regulator of muscle protein synthesis. mTOR activation is required for muscle hypertrophy and is the same pathway stimulated by resistance exercise and leucine.
Catabolic inhibition and eNOS stimulation
Strengthera is proposed to reduce muscle protein breakdown while supporting nitric oxide production, which may improve blood flow and nutrient delivery to working muscle. These are proposed effects and have not been directly confirmed in people.
Clinical trials
8-week randomized, double-blind, placebo-controlled trial in 99 healthy young men (average age 22) who did resistance training three times a week while taking the blend or placebo. The page previously described a 12-week trial in adults aged 55 to 70, but no such trial has been published or can be found in the medical literature, so its results cannot be verified.
99 young men (age 22 ± 3) randomized to one of four arms: A1 (425 mg SMI + 1 RET set), A2 (850 mg SMI + 1 RET set), P1 (placebo + 1 RET set), P2 (placebo + 2 RET sets). 3×/week resistance training (bench press + leg extension) at 80% 1-RM for 8 weeks. Same Sphaeranthus indicus + Mangifera indica blend (LI12542F6) as RipFACTOR® and TestFACTOR®.
Resistance training significantly increased 1-RM, repetitions to failure, and testosterone in all groups (p<0.05), but the supplemented groups showed greater gains than placebo or doubled-volume placebo. This shows the blend can add to resistance-training gains in young men, not that it works on its own. Foundational young-male trial; (n=40 young men) provides additional support for muscle strength and endurance. A 92-pt 55-70 trial is pending publication for the over-55 demographic.
Clinical trial of SMI botanical blend (425 mg and 850 mg/day) vs. placebo in 99 men aged 22±3 performing resistance training for 8 weeks.
99 healthy young men. 8-week resistance training + supplementation protocol.
Both SMI doses significantly augmented bench press and leg extension strength and repetitions-to-failure beyond exercise alone. Testosterone levels increased significantly in supplemented groups. Published in Frontiers in Nutrition, 2024.