Gross profit in the second quarter of 2023 increased $5.1 million, or 11.7%, to $48.3 million, compared to $43.2 million in the second quarter of 2022. Gross margin was 70.7% of revenue, compared to 72.5% of revenue in the second quarter of 2022. Non-GAAP gross margin was 71.1% of revenue, compared to 73.0% of revenue in the second quarter of 2022.
Operating expenses in the second quarter of 2023 decreased $1.1 million, or 2.3%, to $46.2 million, compared to $47.3 million in the second quarter of 2022.
Operating income was $2.1 million in the second quarter of 2023, compared to an operating loss of $4.1 million in the second quarter of 2022. Non-GAAP operating income in the second quarter of 2023 was $3.6 million, compared to a non-GAAP operating loss of $1.8 million in the second quarter of 2022.
Other expense was $0.8 million in the second quarter of 2023, compared to $0.6 million in the second quarter of 2022.
Income tax expense was $1.3 million in the second quarter of 2023, compared to an income tax benefit of $20,000 in the second quarter of 2022.
Net loss in the second quarter of 2023 was $0.1 million, or $0.00 per diluted share, compared to $4.6 million, or $0.23 per diluted share, in the second quarter of 2022. Non-GAAP net income in the second quarter of 2023 was $1.0 million, compared to a non-GAAP net loss of $2.9 million in the second quarter of 2022.
Weighted average shares used to compute diluted net loss per share were 23.4 million and 20.0 million for the second quarters of 2023 and 2022, respectively.
Adjusted EBITDA was $6.1 million in the second quarter of 2023, compared to $1.7 million in the second quarter of 2022.
First Six Months 2023 Financial Results:
Total revenue for the six months ended June 30, 2023, increased $19.6 million, or 18.2%, to $127.2 million, compared to $107.6 million for the six months ended June 30, 2022. The increase in revenue was attributable to an increase of $17.5 million, or 18.9%, in sales and rentals of the lymphedema product line and an increase of $2.1 million, or 13.7%, in sales and rentals of the airway clearance product line.
Net loss for the six months ended June 30, 2023, was $2.0 million, or $0.09 per diluted share, compared to $20.2 million, or $1.01 per diluted share, for the six months ended June 30, 2022. Non-GAAP net income for the six months ended June 30, 2023, was $0.4 million, compared to a non-GAAP net loss of $11.4 million for the six months ended June 30, 2022.
Weighted average shares used to compute diluted net loss per share were 22.3 million and 20.0 million for the six months ended June 30, 2023 and 2022, respectively.
Adjusted EBITDA was $6.6 million in the six months ended June 30, 2023, compared to adjusted EBITDA loss of $0.9 million in the six months ended June 30, 2022.