I am 35y male with skin type III. I’ve had six sessions (8-10 weeks)on my back and shoulders with I believe 15mm 24J with ok results. I am going ask my practitioner to use 18mm/20J which is the setting many on this forum recommend. Would 15mm/30J penetrate deeper and give better results?
If the hair is coarse as well then a Yag laser would go the deepest as they have the deepest penetration of all lasers, but work best on very coarse hair.
Larger spot size is always better. So go with 18mm/20J. It’s technically equivalent to 15mm/30J, but 18mm penetrates deeper. Some clinics use the smaller spot size to try to target the finer less deep hairs, but the industry opinions vary on whether this actually makes a difference.