A number of supplements have been shown to promote strength by supporting muscle function. These include the following:
Carnitine. Carnitine is an amino acid that helps transport fat into mitochondria, where it is metabolized. Exercise capacity is increased among people with arterial disease following carnitine supplementation (Barker 2001). In addition, studies show that carnitine supplementation increases muscle function and exercise capacity in people with kidney disease (Brass 1998).
Carnosine. Carnosine is found in high amounts in skeletal muscle; muscle levels of carnosine are elevated during peak activity (Suzuki 2002). Among other reported advantages, carnosine scavenges free radicals, which is important because exercise produces abundant free radical activity (Boldyrev 1997; Wang 2000; Yuneva 1999; Nagasawa 2001). Additionally, carnosine protects against cross-linking and advanced glycation end product formation, both of which damage protein (Hipkiss 1995; Munch 1997). Carnosine also acts as a pH buffer, protecting muscles from oxidation during strenuous exercise (Burcham 2000).
Coenzyme Q10 (CoQ10). CoQ10 is a critical component in the conversion of food and oxygen to ATP (the body’s universal energy source). ATP acts as a short-term reserve to power everything from muscle activity to brain work. Over time, mitochondrial oxidant damage depletes CoQ10 stores (Lönnrot 1995; Di Meo 2001; Genova 2004). Depleted CoQ10 and related mitochondrial dysfunction are major contributors to age-related diseases as well as aging itself (Wallace 2009). Aged and damaged mitochondria with insufficient CoQ10 operate inefficiently, producing less energy and more reactive oxygen species (Choksi 2007). This produces more mitochondrial oxidant damage, driving a vicious cycle (Di Lisa 2009).
Shilajit. Long known to Ayurvedic practitioners for its healing power, shilajit is an organic substance harvested from biomass high in the Himalayas (Schepetkin 2009; Goel 1990). It acts as a powerful adaptogen, providing broad systemic defense against stress and illness. Cutting-edge scientific analysis has isolated humic substances as the principal active ingredients that enhance mitochondrial energy flow (Agarwal 2007).
In 2009, a series of landmark studies detailed for the first time how shilajit works on energy metabolism.
Mice subjected to strenuous exercise experienced ATP declines in muscle, blood, and brain tissue. When supplemented with shilajit, ATP loss was sharply reduced (Bhattacharyya 2009) and other biochemical markers of energy status dramatically improved. CoQ10, in particular, fell twice as fast in control mice as in supplemented mice. When given in combination, CoQ10 and shilajit displayed a more powerful synergistic effect than either alone.
Further analysis brought some of its key mechanisms of action to light. Shilajit contains two primary components, fulvic acid and dibenzo-a-pyrones (DBPs). Fulvic acid independently stimulates mitochondrial energy metabolism, protects mitochondrial membranes from oxidative damage, and helps channel electron-rich DBPs into the mitochondria to support the electron transfer chain (i.e., a series of reactions coupled to the formation of ATP) (Piotrowska 2000; Ghosal 2006). Fulvic acid works as an electron “shuttle,” augmenting CoQ10 to speed electron flow within mitochondria (Visser 1987; Royer 2002; Kang 2009).
When laboratory mice were supplemented with oral CoQ10 alone, CoQ10 levels increased in heart, liver, and kidney tissue (Bhattacharyya 2009). When DBPs from shilajit were added to the supplement, CoQ10 levels increased further—as much as 29% in the liver (Bhattacharyya 2009).
A recent study suggests that DBPs from shilajit preserve CoQ10 in its superior ubiquinol form (Bhattacharyya 2009).
Preliminary findings suggest that shilajit protects human tissue from lost energy in the form of ATP, while maximizing benefits from CoQ10, with dramatic improvement in exercise performance (Pal 2006). In an unpublished study, people who took shilajit 200 mg once daily for 15 days registered 14% higher post-exercise ATP levels in the blood—equivalent to levels in people who had not exercised at all. The average number of steps taken on a standardized dynamic exercise test rose significantly, and mean fitness scores increased by 15%—without any intervening exercise training.
Creatine. Studies show that creatine supplementation effectively increases lean muscle mass and strength (Nissen 2003; Kreider 2003; Gotshalk 2002). Creatine donates a phosphate molecule to adenosine diphosphate (ADP) to produce more ATP for energy demands. Lactic acid buildup may also be delayed after creatine supplementation.
Studies support the use of creatine to increase strength in older people (Gotshalk 2002; Chrusch 2001). Other studies demonstrate that creatine can help those with degenerative neurological disorders and enhance memory in older adults (Wyss 2002; Beal 2003; Tarnopolsky 2001; Matthews 1998; Tabrizi 2003; Laakso 2003; Yeo 2000; Valenzuela 2003; Watanabe 2002; Rae 2003).
Branched-chain amino acids. Amino acids are the building blocks of protein. Essential amino acids, (i.e., those not synthesized by the human body) must be obtained from outside sources. The essential branched-chain amino acids (isoleucine, leucine, and valine) improve performance and prevent muscle metabolism during endurance exercise (Workman 2002; Shimomura 2006; Ohtani 2006). In a study comparing amino acid and carbohydrate supplements, amino acid supplements improved walking and isometric muscle strength in older participants (Scognamiglio 2004).
Glutamine. Although the most abundant amino acid in the body, at times the body cannot produce all the glutamine it needs due to extreme stress caused by surgery, prolonged exercise, or infection (Talbott 2003; Workman 2002; Hendler 2001; Bassit 2002).
Various studies have shown the beneficial properties of glutamine during exercise. Athletes who engage in strenuous activity are at elevated risk of developing an upper respiratory infection. This heightened risk could be due to decreased glutamine as a result of intense exercise (Castell 2002; Parry-Billings 1990). Glutamine supplementation resulted in a reduction of respiratory infection in a study of marathon runners (Castell 1996).
Glutamine, in conjunction with L-cysteine and glycine, helps promote the synthesis of glutathione (a powerful antioxidant) and regulate muscle metabolism (Rennie 1998). Glutamine helps build and maintain lean muscle tissue (Workman 2002). If levels are low, the body may break down muscle to obtain glutamine, resulting in low muscle mass. Supplemental glutamine may prevent muscle breakdown as well as promote greater protein synthesis (Antonio 2002; Hankard 1996).
Metabolic whey protein. Protein supplementation has been used by fitness enthusiasts and athletes for many years. After exercise, when the body is in a catabolic state, protein supplementation can help protect the body’s muscles from being metabolized for energy. Whey protein, in particular, is easily digestible and immediately available to the body. In a study comparing protein and carbohydrate supplements, participants in the protein group showed greater mechanical muscle function during resistance training than participants in the carbohydrate group (Andersen 2005).
Plant protein. In addition to being a source of protein suitable for vegetarians, research has shown that consumption of high-quality vegetable protein exerts numerous beneficial effects in aging humans. Pea protein contains more glutamine than whey or egg protein, with comparable BCAA values to whey, egg, and casein. It also contains more arginine than these ‘gold standard’ animal proteins. Arginine is essential for nitric oxide synthesis, which promotes healthy endothelial function and blood vessel dilation and relaxation (Zhou 2001).
Polyenylphosphatidylcholine. Polyenylphosphatidylcholine (PPC) is a phospholipid that contains polyunsaturated fatty acids, including linoleic and linolenic acid. In addition to providing flexibility to the cell membrane, PPC can help maintain plasma choline levels during exercise. Choline, which is depleted during exercise, assists in acetylcholine formation. Acetylcholine is involved in the relay of muscle contraction signals across nerve synapses (Buchman 2000).
Vitamin D. While scientists have long known that vitamin D plays an important role in bone health, recent studies suggest that it is also essential for maintaining muscle mass in the aging population. Vitamin D helps preserve Type II muscle fibers that are prone to atrophy in the elderly. Scientists noted that vitamin D helps support both muscle and bone tissue, and low vitamin D levels seen in older adults may be associated with poor bone formation and muscle function. Thus, ensuring adequate vitamin D intake may help reduce the incidence of both osteoporosis and sarcopenia in the aging population (Montero-Odasso 2005).
D-Ribose. D-ribose, a carbohydrate molecule found in every living organism, facilitates the production of ATP (Dodd 2004).
One study found that exercise-induced physical fatigue was the most important reason people stopped their workouts (Annesi 2005). Vigorous exercise can drop muscle ATP levels by up to 20%, with up to a 72-hour recovery period for muscles that have been worked hard (Hellsten-Westing 1993; Stathis 1994).
The “wiped-out” feeling many of us experience after exercise is also caused by the leakage of ATP breakdown products from muscles into the bloodstream (Hellsten 1999). Once again, D-ribose is vital to keeping our muscles’ ATP-based energy stores at peak capacity (Tullson 1988; Zarzeczny 2001), which can mean less “afterburn” and more enthusiasm for the next workout.
Exercise physiologists showed that supplementing muscles with D-ribose resulted in an up to four-fold increase in the total amount of ATP produced, providing a substantial “bank” of energy to be called upon for use when needed (Tullson 1991). When physiologists provided D-ribose to working muscles, they demonstrated up to a six-fold rise in the rate at which ATP components were recycled for use (recycling ATP is much faster and more efficient than building it from scratch) (Zarzeczny 2001; Brault 2001).
Sport and exercise physiologists showed that human muscle lost ATP after extreme exercise (mimicking experimental models) and also noted that exhausted muscles took longer to replenish ATP levels than rested muscles (Hellsten-Westing 1993). That led them to speculate that supplementing human sprinters with D-ribose might speed the recovery of their muscles’ ATP levels.
In 2004, a landmark paper showed that three-times daily supplementation with D-ribose for three days following extreme sprint training caused ATP levels to return to normal within 72 hours, while ATP levels remained depressed in placebo recipients (Hellsten 2004).