Sodium bicarbonate is a well researched supplement that may provide a performance benefit during high intensity exercise by acting as an extracellular buffer and raising blood pH. The dose that seems most efficacious is 0.2-0.4 g/kg body weight taken 1-2.5 hours before a high intensity workout or race. The downside of ingesting sodium bicarbonate is possible GI distress, making it a questionable choice before an important workout or event.
For this reason, a topical sodium bicarbonate supplement has been created with the claim that the buffering benefits would be retained as the supplement absorbs through skin, bypassing the gut and removing the risk of GI issues.
But, does it work?
A recent placebo controlled study compared oral ingestion with topical application of sodium bicarbonate in recreationally trained athletes. The main outcome variables included time to fatigue and blood measures (pH, HCO3-, and blood lactate concentration) at rest and following post-exercise-induced fatigue. In a follow up protocol, the researchers completed a second placebo-controlled examination of topical sodium bicarbonate versus placebo lotion and measured mean and peak power output during serial Wingate tests in moderately trained athletes.
Findings from both studies indicated no effect of topical sodium bicarbonate on blood parameters indicative of buffering capacity or performance outcomes. This is likely due to insufficient transdermal absorption of the topical supplement as blood concentration of HCO3- and pH were only elevated in the oral supplementation trial.
Takeaway: If you want the benefits of sodium bicarbonate, stick to an oral supplementation plan that works best for you and trial it under various conditions during training. To minimize the likelihood of GI distress, consume with a meal/snack containing ~1.5 g of carbohydrate /kg of body weight.
PMID: 32575069; 29540367