Benefits
Raises blood ketone (BHB) levels for several hours
In healthy adults, 34.5 g split into three servings raised blood BHB from about 0.2 to a mean peak of 2.1 mmol/L at about 2 hours, still above baseline at 5 hours. In 12 heart patients, one 0.5 g/kg dose kept BHB raised across 6 hours. A 10 g dose gave a lower peak than the same amount of ketone monoester. A higher ketone reading is a change in blood chemistry, not a benefit in itself.
Lower blood glucose after a dose
Blood glucose fell after a 10 g dose in 12 healthy adults, but that study had no placebo arm. In a placebo-controlled crossover in 12 heart patients, one dose lowered glucose by about 0.4 mmol/L. During exercise, results varied: lower in one cycling trial, unchanged in another, higher after a running time trial. The drop is small and short-lived; anyone on glucose-lowering medicine should check with their doctor first.
Endurance performance in cycling and running time trials
Three small crossover trials found no performance gain. Racemic 1,3-butanediol did not change cycling time-trial time or power in 9 trained cyclists. Added to carbohydrate, 1,3-butanediol did not change 5 km running time in 11 runners or 16.1 km cycling time in 9 keto-adapted men, even though blood BHB rose each time. Digestive symptoms were common in the first cycling study.
Hunger and alertness after a single dose
In a 12-person crossover study, 10 g of (R)-1,3-butanediol did not change hunger ratings. In an open-label study of 26 adults, 34.5 g did not change sleepiness scores. No published trial was found that tested (R)-1,3-butanediol on its own for memory or thinking, so claims about mental performance rest on studies of other ketone products.
Mechanism of action
Converted to BHB by alcohol-processing enzymes in the liver
The liver converts (R)-1,3-butanediol to BHB using alcohol dehydrogenase and aldehyde dehydrogenase, the same enzyme families that break down drinking alcohol. This fits with the alcohol-like dizziness or euphoria some people report at higher doses.
Gradual conversion gives longer-lasting ketosis
Because the liver releases BHB from it gradually, blood ketones peaked about 2 to 3 hours after intake and stayed raised for 5 to 6 hours in studies, longer than the 3 to 4 hours reported for BHB given as an intravenous salt or an oral ketone ester. The peak is lower than after a ketone monoester at the same dose.
Lowers circulating fatty acids and glucose while ketones are raised
Raised BHB was accompanied by lower free fatty acids and lower blood glucose in a patient crossover study, with slightly higher insulin than placebo; an early feeding study also reported slightly higher fasting insulin. These are short-term measurements, and their long-term meaning for healthy people is unknown.
Clinical trials
Open-label, single-arm acute study: three 11.5 g servings of (R)-1,3-butanediol (Avela) taken 30 minutes apart after an overnight fast, with blood BHB, digestive symptoms and sleepiness tracked for 5 hours (Lowder et al. 2023, Front Physiol)
26 healthy adults.
Blood BHB rose from about 0.23 to a mean peak of 2.10 mmol/L at roughly 2 hours and stayed above baseline at every time point. Sleepiness did not change. Most people had no or mild digestive symptoms; 5 reported mild headaches, 2 judged possibly related. No placebo group, and the study was funded by the maker.
Double-blind randomized crossover pilot comparing 10 g of the ketone monoester, D-BHB acid with (R)-1,3-butanediol, and (R)-1,3-butanediol alone, with blood BHB and glucose measured for 4 hours (Falkenhain et al. 2024, J Diet Suppl)
12 healthy adults (42% women), average age 29.
All three products raised blood BHB, with the highest peak after the monoester. Blood glucose fell after each product, with no difference between them. Hunger did not change and there was no evidence of digestive distress. There was no placebo arm, so the glucose drop is measured against baseline only.
Randomized crossover study of racemic (R,S)-1,3-butanediol, 0.35 g/kg taken before and again during 85 minutes of steady cycling that preceded a time trial, versus placebo (Shaw et al. 2019, Int J Sport Nutr Exerc Metab)
9 trained male cyclists.
Blood BHB rose during exercise, but time-trial duration (28.7 minutes with butanediol vs 28.5 with placebo) and average power did not differ from placebo. Five riders reported moderate to severe digestive symptoms, and two reported low levels of dizziness, nausea and euphoria.
Randomized crossover study comparing a carbohydrate drink with added 1,3-butanediol against an energy-matched carbohydrate drink before 60 minutes of running and a 5 km time trial (Scott et al. 2019, J Sci Med Sport)
11 male runners.
Blood BHB was at least double with the butanediol drink, and blood lactate was slightly lower after 30 minutes, but 5 km time did not differ (1,261 seconds with butanediol vs 1,265 without). Blood glucose was higher after the time trial with the butanediol drink.
Single-blind counterbalanced crossover: 60 g carbohydrate with or without 0.5 g/kg of a commercial 1,3-butanediol product before 60 minutes of steady cycling and a 16.1 km time trial (Carpenter et al. 2026, Nutrients)
9 recreationally active men on a ketogenic diet for at least a year.
Blood BHB was higher with butanediol (1.69 vs 0.55 mmol/L after exercise), but time-trial time did not differ (1,620 vs 1,606 seconds), nor did substrate use, heart rate or effort ratings. Glucose was lower at 40 and 60 minutes of steady exercise. The authors note the small sample and limited power.
Randomized, single-blind, placebo-controlled crossover study of one oral dose of (R)-1,3-butanediol (0.5 g/kg) with measurements every hour for 6 hours (Guldbrandsen et al. 2025, J Am Heart Assoc)
12 patients with heart failure with reduced ejection fraction, all on standard medical therapy.
Circulating BHB rose by about 1,400 micromol/L on average across 6 hours versus placebo. Blood glucose (by about 0.4 mmol/L) and free fatty acids fell, and cardiac output rose. No adverse events were reported. This is a hospital study in patients under medical care, not a reason to self-treat.
Double-blind, placebo-controlled remote pilot of a drink with 5 g R-BHB acid and 5 g (R)-1,3-butanediol taken three times daily for 90 days; feasibility was the main aim (Marcotte-Chénard et al. 2025, J Am Nutr Assoc)
40 adults with type 2 diabetes.
Feasibility was mixed: 40% of the ketone group dropped out versus 10% on placebo, mostly because of digestive symptoms and taste. Those who continued drank most servings. Continuous glucose monitoring suggested lower glucose, but this was exploratory. A combination product, not butanediol alone.
Single-blind crossover study: a drink with 25 g of ketones from D-BHB acid plus (R)-1,3-butanediol, or placebo, taken 30 minutes before a moderate oral alcohol dose (Li et al. 2024, Int J Neuropsychopharmacol)
10 healthy adults (3 women).
The ketone drink lowered breath and blood alcohol levels and reduced how much participants liked the alcohol. Two participants had blood glucose below 70 mg/dL after the ketone drink. A combination product in a small study; it shows the two interact, not that the drink makes drinking safe.