Inosine

What does it do? Inosine is a nucleoside, one of the basic compounds comprising cells. It is a precursor to adenosine, an important energy molecule, and plays many supportive roles in the body. Based upon anecdotal reports by Russian and Eastern European athletes, inosine has been investigated for ergogenic (exercise boosting) effects. However, controlled studies have concluded that inosine does not improve athletic performance and may even impair it.1 2

Inosine is a precursor to uric acid, a compound that occurs naturally in the body. Uric acid is believed to block the effect of a toxic free-radical compound (peroxynitrite) that may play a role in the development of multiple sclerosis (MS).3 In an attempt to raise uric acid levels, ten patients with MS were treated with inosine in amounts up to 3 grams per day for 46 weeks. Three of the ten treated patients showed some evidence of improved function and the others remained stable.4 Controlled studies are needed to confirm these preliminary results.

Where is it found? Inosine is found in brewer’s yeast and organ meats. It is also available as a supplement.

Inosine has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating Health Concerns
1Star Multiple Sclerosis
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

Who is likely to be deficient? Inosine is not an essential nutrient, so deficiencies do not occur.

How much is usually taken? Although a common amount of inosine taken by athletes is 5,000–6,000 mg per day, little scientific evidence supports the use of this supplement in any amount.

Are there any side effects or interactions? No side effects have been reported with the use of inosine for two to five days in the limited research available. However, unused inosine is converted by the body to uric acid, which may be hazardous to people at risk for gout.

At the time of writing, there were no well-known drug interactions with inosine.

References:

1. Starling RD, Trappe TA, Short KR, et al. Effect of inosine supplementation on aerobic and anaerobic cycling performance. Med Sci Sports Ex 1996;28:1193–8.

2. Williams MH, Kreider RB, Hunter DW, et al. Effect of inosine supplementation on 3-mile treadmill run performance and VO2 peak. Med Sci Sports Exerc 1990;22:517–22.

3. Koprowski H, Spitsin SV, Hooper DC. Prospects for the treatment of multiple sclerosis by raising serum levels of uric acid, a scavenger of peroxynitrite. Ann Neurol 2001;49:139.

4. Koprowski H, Spitsin SV, Hooper DC. Prospects for the treatment of multiple sclerosis by raising serum levels of uric acid, a scavenger of peroxynitrite. Ann Neurol 2001;49:139.