Gross Profit
Gross profit margin for the three months ended June 30, 2023 was 67%, compared to 71% for the three months ended June 30, 2022. Gross profit margin for the six months ended June 30, 2023 was 69%, compared to 72% for the six months ended June 30, 2022.
The decrease in gross profit margin % for both comparative periods was primarily due to the integration and launch of several new products, product mix impacts associated with sales of these new offerings, and price increases of certain component parts. In general, we believe gross margins will return to historic levels in the coming quarters.
Research and Development
Research and development expense for the three months ended June 30, 2023 was $859, compared to $319 for the three months ended June 30, 2022, an increase of $540 or 169%. Research and development expense for the six months ended June 30, 2023 was $1,777, compared to $670 for the six months ended June 30, 2022, an increase of $1,107 or 165%.
The increase for both comparative periods was primarily driven by our continued buildup of internal capabilities to develop, test, and manufacture our next generation of diagnostic products.
We anticipate that R&D costs will increase as we maintain and enhance our current product lines and continue to develop new products.
Selling, General, and Administrative
Selling, general, and administrative expense for the three months ended June 30, 2023 was $9,931, compared to $8,567 for the three months ended June 30, 2022, an increase of $1,364 or 16%. Selling, general, and administrative expense for the six months ended June 30, 2023 was $20,360, compared to $15,270 for the six months ended June 30, 2022, an increase of $5,090 or 33%.
The increase for both comparative periods was primarily driven by salaries and noncash stock option expense associated with increased hiring campaigns, noncash amortization related to our Assisi / Revo acquisitions, recruiting and other related fees associated with our transition to a new Chief Financial Officer, and increased marketing campaigns / attendance at tradeshows to build brand awareness and recognition of our expanding suite of products.
We expect future selling, general and administrative expense to increase in line with product expansion and growth in our commercialization efforts.
Net Loss
Net loss for the three months ended June 30, 2023 was $5,249, compared to a loss of $5,273 for the three months ended June 30, 2022, a decrease of $24 or 1%. Net loss for the six months ended June 30, 2023 was $11,634, compared to a loss of $9,210 for the six months ended June 30, 2022, an increase of $2,424 or 26%.
The net loss for each comparative periods was attributed to the matters described above. We expect to continue to record net losses in future periods until such time as we have sufficient revenue from product sales to offset our operating expenses.