TOPLINE

Adults with overweight or obesity who received a bitter hop extract (BHE) alongside monthly lifestyle advice lost more than 4% of their body weight and nearly 5 kg of fat mass over 24 weeks. Muscle mass was preserved suggesting the supplement may support fat-specific weight loss without compromising lean tissue. 

METHODOLOGY

• Researchers conducted a randomized double-blind, parallel-group trial over 24 weeks in Auckland, New Zealand, enrolling 150 adults aged 18-45 years with a BMI of 25-35 kg/m².
• Participants attended monthly 1-hour group seminars providing general diet and exercise advice, including recommendations for protein at every meal, limiting unhealthy snacks, eating nutrient-dense foods, and exercising daily.
• A total of 128 participants completed the program; 65 received 500 mg once daily of Amarasate BHE in delayed-release capsules, and 63 received matched placebo, with doses split before two main meals and escalated over 3 weeks.
• Body weight and bioelectrical impedance analysis (BIA) estimates of body composition were measured every 4 weeks, alongside visual analogue scale (VAS) assessments of appetite and food cravings.
• Primary outcomes included changes in body weight, fat mass, visceral fat area, and muscle mass; secondary outcomes included subjective hunger, food cravings, and gastrointestinal (GI) side effects.

TAKEAWAY

• At 24 weeks, the BHE group exhibited a mean reduction of 4.3% in body weight (3.8 kg) from baseline, compared with 0.5% (0.4 kg) in the placebo group, representing a 3.8% greater weight loss (P < .05).
• Fat mass decreased by 4.5 kg in the BHE group vs 0.7 kg in placebo, a difference of 3.9 kg (P < .05), with significant reductions observed from week 12 onward.
• Visceral fat area declined by 33 cm² in the BHE group compared with 9 cm² in placebo, a difference of 24 cm² (P < .05), with consistent loss throughout the intervention.
• Muscle mass increased by approximately 1 kg in the BHE group and 0.3 kg in placebo, with no significant treatment effect — indicating that lean tissue was not only preserved but slightly increased during weight loss in both groups.
• Subjective hunger ratings decreased significantly in the BHE group relative to baseline (P < .05) and were lower than placebo at weeks 4, 8, 12, and 20 (P < .05).
• Cravings for food in general, fatty food, salty food, and savory food were significantly reduced in the BHE group at all timepoints compared with baseline (P < .05), with significant differences from placebo at multiple timepoints.
• Energy intake decreased by 748 kJ and 545 kJ more in the BHE group than placebo at weeks 12 and 24, respectively (P < .05).
• Dose adjustment was required in approximately 10% of BHE-treated participants to manage GI side effects, primarily diarrhea and nausea; one participant in each treatment group withdrew due to side effects. Overall, GI symptom increases were small, non-significant, and largely confined to the week-4 dose-escalation period.

IN PRACTICE

"These data suggest that appetite suppressing nutraceuticals may be a useful adjunct therapy for individuals receiving lifestyle change advice for the purpose of weight loss," wrote the authors of the study.

SOURCE

The study was led by Edward Walker, New Zealand Institute for Bioeconomy Science Limited in Auckland, New Zealand. It was published online on July 17 in Obesity Pillars.

LIMITATIONS

Researchers recruited only healthy adults with overweight or obesity without comorbidities, limiting generalizability to populations with obesity-related conditions. Body composition was assessed by BIA rather than DEXA or MRI, which may affect precision of fat and muscle mass estimates. Energy intake was self-reported via 4-day diet diaries, which are prone to underreporting. The study included a higher percentage of female participants and excluded individuals older than 45 years, potentially introducing gender and age bias.

DISCLOSURES

Calocurb Ltd and The New Zealand Institute for Bioeconomy Science Limited, a government-owned public research organization, provided funding for the study. The New Zealand Institute for Bioeconomy Science Limited has licensed a bitter hop extract as a dietary supplement to Calocurb Ltd and holds a minor shareholding in the company. The authors reported no personal competing financial interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.